Occupations and Breast Cancer
Evaluation of associations between breast cancer and workplace exposures

A review prepared for the
Ontario Occupational Disease Panel (Industrial Disease Standards Panel)
Ministry of Labour of Ontario
by France Labrèche, PhD, Epidemiologist

Occupational and Environmental Health Unit
Montreal Public Health Department and
Joint Departments of Epidemiology and Biostatistics, and Occupational Health
McGill University, Montréal

December 23, 1997

Background and scope of evaluation

This document was prepared as a tool to assist the Ontario Occupational Disease Panel in its examination of the possible occupational associations of breast cancer. The present epidemiologic review evaluates:

  • workplace associations for female and male breast cancer;
  • the evidence concerning environmental (pesticides) exposures, especially as they might pertain to farm workers;
  • and, to a lesser extent, any other possibly significant associations.
  • The section on female breast cancer is fairly exhaustive, but because of restricted time, the section on male breast cancer is less thorough.


    Breast cancer will affect one in nine Canadian women during their lifetime and it is the leading cancer among women; one in 25 women will die from it in Canada, making breast cancer the second cause of cancer deaths, overtaken by lung cancer in 1993. The 1997 incidence rates in Canada range from 93 to 112 per 100,000 [National Cancer Institute of Canada, 1997]. The average incidence rate over 1983-1987 was reported to be 91.1 per 100,000 (ranging from 35.5 to 103.9 per 100,000) [Parkin et al., 1992]. It is estimated that over 18,000 women will be diagnosed with breast cancer in 1997 and more than 5,000 will die of it.

    Incidence rates of female breast cancer have increased over the past few decades in most western countries [Stevens et al., 1982; Holford et al., 1991; Coleman et al., 1993] especially among post-menopausal women [National Cancer Institute of Canada, 1993]. The reasons for this increase are largely unknown, but could be related to early detection in mass screening programs, to temporal changes in recognized and suspected risk factors, to changes in the pathologic definition of breast cancer or to an artifact of detecting "histologically malignant but biologically benign" tumours [Doll and Peto, 1981], or to other unidentified risk factors. It is likely that the known risk factors cannot account for a large fraction of cases or for all of the growth in incidence rates [Kelsey, 1993]; estimated figures to that effect rang from 21% [Seidman et al., 1982] to 41% [Madigan et al., 1995]. Mortality rates have remained fairly stable, declining slightly over recent years [National Cancer Institute of Canada, 1993].

    By contrast, male breast cancer incidence rates are very low, approximately 100 times lower than in women, and have remained stable, as have the mortality rates, for the last 40 years [Sasco et al., 1993; Thomas, 1993]. The highest incidence rate in Canada over 1983-1987 is reported to be in Nova Scotia and New Brunswick, at 0.9 case per 100,000 [Parkin et al., 1992]; the Canadian average was 0.7 per 100,000 for the same period.


    Epidemiological studies with the potential for investigating associations of breast cancer and occupation were identified through MEDLINE searches, published reviews of literature, review of each paper on cancer published in twenty major journals between 1970 and September 1997, and from examining reference lists of retrieved pertinent papers. Only papers published in peer-reviewed journals were retained, excluding abstracts (they often do not contain sufficient information), and articles published in English or in French were retrieved. Studies on female breast cancer published until 1994 had already been reviewed thoroughly for a previous publication [Goldberg and Labrèche, 1996]: the female breast cancer part of the present work is an update of that review. Two recent reviews on male breast cancer were used as a starting point for the male breast cancer part [Sasco et al., 1993; Thomas, 1993]; these papers mentioned only EMF exposure as a possible occupational factor in male breast cancer.

    Because of time constraints, the MEDLINE search on male breast cancer was restricted to publications that contained the MeSH term: breast neoplasms/male'; this means that general mortality studies where figures are reported for male breast cancer, but where it was not mentioned in the abstract, could have not been all indexed in MEDLINE and would thus have been missed.

    More than 170 reports from over 130 independent studies that presented risk estimates for breast cancer were reviewed. Studies were classified by type of design, namely descriptive studies including analysis of routinely collected data, general population surveys and registry linkage studies, and analytical studies including case-control and cohort studies. Some investigations did not however fit neatly into one category. Case reports and case series were not considered in this review because of their anecdotal nature and descriptive studies on cancer in males were not reviewed.

    Investigations based on routinely collected data, labelled as descriptive studies here, may convey spurious conclusions if used by themselves, although they can be used for generating hypotheses. The principal limitations of descriptive studies include: 1) misclassification of disease status, 2) misclassification of exposure, 3) lack of control of confounders and 4) absence of exposure-response indices. 1) Misclassification of disease status can lead to reductions in statistical power and attenuation of risk ratios. Mortality data are more susceptible to these types of problems than incidence data. 2) Misclassification of exposure through the use of coarse occupational categories will lead to an attenuation of risk ratios. In the studies we reviewed, exposure was usually classified in terms of the last occupation (or industry) or the occupation of the longest duration. This can also lead to bias, possibly away from the null, if workers changed occupations because of illness. Notable exceptions were the Chinese study by Zheng and coworkers [1993], in which occupational histories were obtained directly from subjects (although denominators were based on census data). 3) Inability to account for key confounding factors may lead to incorrect inferences. In none of the investigations based on administrative data were important risk factors for breast cancer accounted for. That incorrect conclusions may be drawn from descriptive studies is showed by the observation that although increased risks of developing breast cancer for clerical and white collar jobs were observed in studies using administrative data, no association was observed in the cohort or case-control studies. It is also possible that the studies of exposure to extremely low frequency electromagnetic fields, also based on routinely collected data, were also biased [Trichopoulos, 1994]. 4) Lastly, no estimates of risk by duration of employment, latency, or other indices of exposure-response were presented in the reviewed papers, thus making it difficult to assess the veracity of the associations.

    More weight is given in this paper to analytical studies because of their better adjustment for confounding factors and more careful ascertainment of disease and exposure or occupation. Standardised ratios were preferred to proportionate ratios, because the former are more robust against the healthy worker effect'. Incidence data were preferred to mortality data because of the relatively long survival from breast cancer (5-year survival of 75% in Canada). When more than one comparison group was used, the risk estimate obtained with the most appropriate one was retained (i.e. local versus national, working population versus population including the unemployed, comparable or similar occupations versus dissimilar occupations). Increased comparability also makes studies done in North America preferable to studies from other parts of the world because more similar types of industries and occupational exposures, lifestyles and genetic make-up of the population are expected within a continent.

    In terms of other potential confounding factors, as reproductive factors are distributed unevenly in the population, the exclusion of homemakers in the comparison group could help decrease part of the confounding effect of reproductive factors. This has been verified in a descriptive study on teachers and nurses [King et al., 1994], where the PMR estimates were reduced when homemakers were removed from the reference group, thus suggesting that some or all of the excess risk may be due to confounding by reproductive factors.


    Most of the published studies relevant to breast cancer and occupational exposures used routinely collected data and covered a wide variety of occupational circumstances, from different parts of the world. These descriptive studies can be considered as indicators of possible associations, but because of their methodological weaknesses, stated before, one must rely on analytical studies to draw conclusions on the possibility or probability that an association seen may be judged as causal.

    Among the analytical studies, occupational cohort studies, especially of mortality, are by far the most numerous. More than thirty different occupations or industries were investigated in the cohort studies, as well as close to 20 different exposures to chemical agents. Although we calculated for the females breast cancer studies that statistical power (to be able to show a risk of 2) was above 80 percent in about three quarters of the studies, the small number of observed cases indicates that the power to detect excess risks in sub-groups and to test for trends in exposure was generally low [Goldberg and Labrèche, 1996]. A variety of indices or surrogates of exposure were used in these studies, but in fewer than 15 studies were breast cancer risks actually presented according to level or duration of exposure.

    Although numerous case-control studies have been conducted on female breast cancer, only seven of them documented occupation as a potential risk factor, in addition to some that reported solely on physical activity in relation to occupation [Vena et al., 1987; Vihko et al., 1992; Dosemeci et al., 1993; Zheng et al., 1993; D'Avanzo et al., 1996; Coogan et al., 1997]. Of the seven case-control studies identified, four were population-based [Williams et al., 1977; Franceschi et al., 1993; Habel et al., 1995; Coogan et al., 1996a; Coogan et al., 1996b], one was based on patients admitted to Roswell Park Memorial Institute, Buffalo, NY [Decoufle et al., 1977], one was a nested study among patients referred to a breast cancer screening clinic in New York City [Koenig et al., 1991], and the seventh was a study within a cohort of radiologic technologists [Morin Doody et al., 1995]. In general, the response rates were adequate and control populations were selected appropriately. Franceschi et al. [1993] focused on farming and agricultural occupations and Koenig et al. [1991] studied cosmetologists. As male breast cancer rates are very low, its rarity explains the relative paucity of published large case-control studies; however, in most of these studies, occupation has been documented.

    As requested by the Ontario Disease Panel, the studies published on exposure to electromagnetic fields and organochlorine compounds, with a special reference to pesticides and farming, will be reviewed in more detail here.

    Potential exposure to electromagnetic fields: Stevens and colleagues hypothesized that breast cancer risk may be increased by exposure to electromagnetic fields (EMFs): through a reduction in melatonin production, these fields could interfere with the oncostatic properties of melatonin and allow levels of estrogen and prolactin to increase [Stevens, 1987; Stevens et al., 1992]. Thus, EMFs may indirectly affect hormonal secretions thereby increasing breast cancer risk. Although several authors have debated the issue, few epidemiologic studies have been carried out among workers exposed to EMFs. A few descriptive studies have shown associations between female breast cancer and a variety of occupations, such as electronic engineering technicians, telephone operators, communication workers, and electrical workers (Table 1) [Doebbert et al., 1988; Bulbulyan et al., 1992; Aronson and Howe, 1994; Loomis et al., 1994; Cantor et al., 1995; Morton, 1995], and one study showed increased risks among office workers, engineers and technicians employed in the telephone industry, with higher risks among black women [Dosemeci and Blair, 1994]. One descriptive study showed increased risks of male breast cancer among workers in electrical transportation [Tynes and Andersen, 1990].

    Two cohort studies among females and five among males were identified (Table 1). One cohort study of telecommunications workers, that had a 75% power to detect a two-fold risk, did not show an increased risk of female breast cancer [Vågerö et al., 1985]. A more recent cohort study of Norwegian female radio and telegraph operators (mostly working on merchant ships) showed an increased incidence of breast cancer of 1.5 compared to the general population of Norway, based on 50 cases (95% CI=1.1-2.0); cases over 50 years old at time of diagnosis had a significant increase in risk with duration of employment and exposure to shift work including night shift [Tynes et al., 1996]. One cohort study, based on only 2 cases, suggested an association among male telephone workers (SIR=6.5, 95% CI=0.79-23.5) [Matanoski et al., 1991]. A Norwegian study has shown an association with employment in "electrical occupations" (12 cases; SIR=2.07, 95% CI=1.07-3.61) [Tynes et al., 1992]. Two large cohort studies of male electric utility workers were not conclusive as breast cancer was concerned: one presented as a case-control analysis from Ontario, Québec and France [Thériault et al., 1994], and one in the United States [Savitz and Loomis, 1995]. An increased incidence of breast cancer was reported among a Swedish cohort of male railway workers, based on 3 cases among engine drivers and conductors (RR=4.9, 95% CI=1.6-15.7); these workers were reported to be exposed to respective average daily means of 4.03:T and 0.61:T, and daily medians of 0.58:T and 0.36:T, for drivers and conductors [Floderus et al., 1994].

    Two case-control studies among females and four among males were found regarding exposure to EMFs (Table 1). One case-control study did not report increased risks among female telephone and other communication operators, with an OR of 0.8 (22 cases; 95% CI=0.4-1.4 ) [Habel et al., 1995]. A recent population-based case-control study found a modest increase in risk for women whose usual job had entailed exposures to 60-Hz magnetic fields (55 cases; adjusted OR=1.43, 95% CI= 0.99-2.09); the increase was however statistically significant for pre-menopausal women (20 cases; adjusted OR=1.98, 95% CI=1.04-3.78). When subgroups of occupations were considered, computer equipment operators had an adjusted OR=1.79 (31 cases; 95% CI=1.03-3.11) [Coogan et al., 1996b]. A large study of male breast cancer (227 cases) found a six-fold increase in electric trades and related occupations (13 cases; OR=6.0, 95% CI=1.7-21) [Demers et al., 1991]. Another case-control study, based on registry data, found an elevated risk among male electrical workers', less than 65 years old at diagnosis, (3 cases; OR=2.2, 95% CI=0.6-7.8) and among telephone workers (1 case; OR=9, 95% CI=0.9-88.7) [Loomis, 1992]. A small case-control study of male breast cancer did not find an excess of EMF-exposed jobs among cases [Rosenbaum et al., 1994]. The most recent case-control study, from Sweden, did not find any increased risk for men exposed at levels of 0.29 to more than 0.41 :T; a job-exposure matrix developed for another study involving EMFs was applied to the reported job titles. The corresponding odds ratios were 0.9 (11 cases; 95% CI=0.4-2.2) and 0.9 (4 cases; 95% CI=0.3-2.7) [Stenlund and Floderus, 1997].

    Unfortunately, in most of the published studies, the exposure data are either more qualitative than quantitative, or based solely on a job title, and information on risk factors other than age is usually missing or indirect at best. Moreover, except for two case-control studies, information on the disease comes from death certificates or disease registries (without histologic confirmation). Several sources of inaccuracy are attached to death certificates, including diagnostic problems (the treating physician may not be aware of the true cause of death or may have difficulty deciding on the direct cause of death), recording problems (especially if the physician who fills the form is not used to the form) and coding problems (arising from disagreement between the coder and the physician on the selection of cause of death or simply clerical coding errors). If one considers incidence data as more appropriate than mortality data, three of the 4 cohort studies present statistically increased risks, and the fourth did not have enough power and also presented an increased risk [Matanoski et al., 1991]. Among the six case-control studies, three had more than 10 cases of breast cancer in a given job title, and two of the 3 presented significant increases [Demers et al., 1991; Coogan et al., 1996b].

    Organochlorine compounds: There are about 15,000 organochlorine compounds, many of these persist in the environment, and some do not [Adami et al., 1995]. These compounds include products that are no longer used (e.g. polychlorinated biphenyls, or PCBs, in electric capacitors and transformers; certain pesticides such as DDT, heptachlor, mirex), and some that still occur as inadvertent contaminants (e.g. dioxins, including TCDD, and furans). The popularized hypothesis linking breast cancer to organochlorines deals not with occupational exposure but to dietary and environmental exposures [Adami et al., 1995]. The focus here will be on occupational exposures, as for the rest of the review.

    Only one descriptive study reported risk estimates for exposure to PCBs or insecticides, stating inconclusive results [Cantor et al., 1995]. Two occupational cohort studies (Table 2) found no increase in the breast cancer mortality risk among female workers exposed to PCBs [Brown et al., 1987; Bertazzi et al., 1987], and Adami et al. [1995] calculated a summary estimate of 0.84 (95% CI=0.50-1.33), based on a total of 18 cases from 4 studies, of which two had not been published. A cohort of male electric utility workers exposed to PCBs was not conclusive [Loomis et al., 1997]. An international cohort study of workers exposed to phenoxy herbicides, chlorophenols and dioxins, from 36 different cohorts, found elevated risks for workers exposed to TCDD [Kogevinas et al., 1997]. The latter concluded that the excess mortality from breast cancer was restricted to one cohort of female workers from Germany (9 cases; SMR=2.84, 95% CI=1.30-5.39); the cohorts from the other countries did not experience increased mortality from breast cancer. The risk was also somewhat elevated among males, based on 2 cases (SMR=2.56, 95% CI=0.31-9.26) [Kogevinas et al., 1997]. A meta-analysis of the TCDD studies produced a summary estimate for female breast cancer of 1.08 (95% CI=0.68-1.58), based on 24 cases [Adami et al., 1995].

    To our knowledge, no case-referent study has been published so far on occupational exposure to organochlorine compounds and breast cancer in women or in men. The available case-control studies compare serum and fat cells content of organochlorines and their metabolites, especially DDT, DDE and PCBs, in cases of breast cancer and in other women [Falck et al., 1992; Wolff et al., 1993; Dewailly et al., 1994; Krieger et al., 1994; Hunter et al., 1997; Lopez-Carrillo et al., 1997; van't Veer et al., 1997]; they can possibly be seen as indirect evidence for an occupational association. So far, the studies produced inconsistent results, more recent studies of larger sample size showing no association [Krieger et al., 1994; Hunter et al., 1997; Lopez-Carrillo et al., 1997; van't Veer et al., 1997]. There are several on-going studies on this issue, and two from Canada should be published shortly [personal communication with Dr. K. Aronson].

    Farmers and gardeners: Seven descriptive studies reported figures for breast cancer risks in relation to farmers: in three of them, there was a significantly reduced risk for females [Kato et al., 1990; Ronco et al., 1992; Wiklund and Dich, 1994], whereas in three others the risks were slightly reduced or close to unity for females [Rubin et al., 1993; Blair et al., 1993; Morton, 1995] and slightly elevated for nonwhite males (4 cases; PMR=1.72, 95% CI=0.46-4.41) [Blair et al., 1993]; in the last one, there was an increased risk of 1.15 among nonwhite females [Austin et al., 1995]. Four cohort studies were found (Table 2), two of them, from Norway and Finland, showing a statistically significant reduction in risk among female farmers (148 cases; SIR=0.84, 95% CI=0.72-0.99) [Kristensen et al., 1996] and 1,474 cases; SIR=0.77, 95% CI=0.73-0.80) [Pukkala and Notkola, 1997]) and a non significant reduction among male farmers or agricultural employees (4 cases; SIR=0.65, 95% CI=0.18-1.51 [Kristensen et al., 1996]/ 11 cases; SIR=0.72, 95% CI=0.36-1.28 [Pukkala and Notkola, 1997]/ 5 cases; SIR=0.48, p>0.05 [Ronco et al., 1992]), while one showed risks close to unity for females [Folsom et al., 1996]. A cohort studying Danish gardeners also found a risk of about one (10 cases among women, no cases among men; SMbR=1.07, 95% CI=0.51-2.11) [Hansen et al., 1992]. A large prospective cohort study of farmers and their families is underway in Iowa and North Carolina (The Agricultural Health Study) [Alavanja et al., 1994] but results are not expected for a few more years. A case-control study reported decreased risks for women in the broad occupational activity of farming, forestry and fishing [Coogan et al., 1996a]. Finally, an Italian multi-site case-control study showed breast cancer risks close to unity among female farmers and did not report any case among males [Franceschi et al., 1993].

    Clerical and professional (other than health services workers): Numerous studies based on administrative data (descriptive studies) reported associations of female breast cancer (incidence or mortality) with clerical and professional jobs, and for a few occupational categories, the number reporting statistically significant excess risks was rather impressive: white collar, professional and managerial occupations, clerical, secretarial, and related jobs, teachers, scientists, and clergy [Doebbert et al., 1988; Bulbulyan et al., 1992; Aronson and Howe, 1994; Katz, 1983; King et al., 1994; Roman et al., 1985; Dosemeci and Blair, 1994; Rubin et al., 1993; Seniori Costantini et al., 1994; Olsen and Jensen, 1987; Kato et al., 1990; Lynge and Thygesen, 1990; Belli et al., 1992; Zheng et al., 1993; Morton, 1995].

    In eight cohort studies involving industrial populations [Bond et al., 1987; Thomas and Decoufle, 1979; Monson and Nakano, 1976; Delzell and Monson, 1981; Béral et al., 1985; Carpenter et al., 1994; Smith et al., 1986; Vaughan et al., 1993; Steenland et al., 1991; Goldberg and Thériault, 1994], female breast cancer risks for a variety of administrative and secretarial or clerical occupations were not greater than expected. By contrast, a cohort study of the workforce in a large chemical plant showed and increased incidence of breast cancer among female salaried employees, most of whom were clerical, technical and professional personnel [Pell et al., 1978; O'Berg et al., 1987]. In addition, a cohort study of female municipal workers did not reveal any associations for professional, clerical and service employees [Vena and Petralia, 1995].

    In one case-control study using main lifetime occupation [Williams et al., 1977], excess risks were observed for clerical workers (335 cases; OR=1.25, p<0.05) and for persons employed in the insurance industry (38 cases; OR=2.83, p<0.05), but significant negative associations were also reported for individuals working in professional and related services (33 cases; OR=0.59, p<0.05), and managers and administrators (39 cases; OR=0.55, p<0.01). In another case-control study designed to study hormone replacement therapy, an increased risk was found for receptionists (24 cases; RR=1.9, 95% CI=1.0-4.0), after controlling for age, parity, education, alcohol intake and body size [Habel et al., 1995]. In the last case-control study, also designed for other purposes, a significantly increased risk of 1.18 (95% CI=1.09-1.27) was found for administrative support occupations, including clerical [Coogan et al., 1996a].

    In view of the fact that exposures to specific occupational agents cannot be identified easily in most of these occupational groups, interpretation of the results is delicate. The excess risks reported for these occupations may have been confounded by reproductive factors, there are no estimates of risk by duration of employment, and there are no obvious occupational exposures.

    Nurses and other health personnel: Health professionals are of considerable interest because they may be exposed to a wide variety of agents, including anaesthetic gases, chemotherapy drugs and organic solvents. However, heterogeneity of occupational exposures complicates the interpretation of associations and pooling large groups of professionals for analysis may dilute the risks. A few administrative studies showed excess risks among nurses, physicians and other health professionals [Doebbert et al., 1988; Bulbulyan et al., 1992; Katz, 1983; King et al., 1994; Roman et al., 1985; Rubin et al., 1993; Olsen and Jensen, 1987; Lynge and Thygesen, 1990; Sankila et al., 1990; Morton, 1995]. Results from earlier cohort studies have been mostly inconclusive for nurse-anesthetists [Corbett et al., 1973], dentistry workers [Cohen et al., 1980], and operating room personnel [Cohen et al., 1974]; one more recent longitudinal study of nurses did not report increased breast cancer risks with respect to the general population [Hunter et al., 1990], but another one showed increasing incidence with duration of follow-up: the standardised incidence rate (SIR) went from 1.3 (95% CI=0.89-1.75) to 3.3 (95% CI=1.21-7.18) for 10 to 50 years between first employment and date of the study [Gunnarsdóttir and Rafnsson, 1995]. Lastly, a cohort study of scientists, laboratory technicians and maintenance workers [Belli et al., 1992] showed a significant increase in the risk of dying from breast cancer (8 cases; SMR=2.88, 95% CI=1.24-5.68). A case-control study designed to investigate the effect of hormone replacement therapy did not find an increased risk for nurses, other health treatment workers, health care assistants and other health technicians, after controlling for reproductive risk factors [Habel et al., 1995]. Another case-control study, investigating an array of dietary and lifestyle risk factors, also presented similar results on breast cancer risk among nurses and other health services occupations [Coogan et al., 1996a].

    Cosmetologists, hairdressers, and beauticians: It is likely that cosmetologists and related workers are exposed to a number of potentially toxic agents, such as hair dyes, organic solvents (in nail products, settings, and hair sprays), and detergents. The International Agency for Research on Cancer (IARC) has classified occupational exposures of haidressers or barbers as probably carcinogenic to humans [IARC, 1993]. Four administrative studies detected significantly elevated relative risks of breast cancer among these workers, ranging from 1.2 to 1.9 [Doebbert et al., 1988; Kato et al., 1990; Lynge and Thygesen, 1990; Morton, 1995]. Of the four cohort studies investigating female cosmetologists, two incidence studies showed increased risks: one found an SIR=1.27 (86 cases; 95% CI=1.01-1.57) among cosmetologists licensed between 1925 and 1934 [Teta et al., 1984], and the other showed a SIR=1.31 (70 cases; 95% CI=1.02-1.65) among female hairdressers during the period of 1970 to 1987 [Pukkala et al., 1992]; the two last studies showed inconclusive results that may be due to low statistical power [Kono et al., 1983; Gubéran et al., 1985]. Two case-control studies designed to look at other risk factors than occupation did not find increased risks for hairdressers, cosmetologists and beauticians together [Habel et al., 1995; Coogan et al., 1996a]. However, in one case-control study designed specifically to look at breast cancer in relation to hair dyes use [Koenig et al., 1991], a relative risk of 3.0 (95% CI=1.1-7.8) was observed among beauticians employed for five or more years; personal use of hair dyes was not associated with breast cancer risk in that study.

    Pharmaceutical industry: A range of studies are available here: pharmacy technicians are not likely to be exposed to the same extent as pharmaceutical manufacturing workers are. Types of exposures also vary, and it is plausible that occupational exposure to sex hormones, espacially during the manufacturing process, can modify the breast cancer risk through a modification in the hormonal balance, both in males and in females. One study based on administrative data showed an excess risk among black women working in the pharmaceutical industry (RR=1.64, p<0.05) [Hall and Rosenman, 1991]. Positive associations were observed in two cohort studies of pharmaceutical workers, with a SMR of 1.79 (22 cases; 95% CI=1.12-2.71) [Thomas and Decoufle, 1979], and a SIR=1.5 (97 cases; 95% CI=1.2-1.8) [Hansen et al., 1994]. There was a suggestion that incidence rates increased by length of service among workers involved in the manufacture of insulin, antibiotics, enzymes, sex hormones and other synthetic drugs, especially among women who started working aged 30 to 39 [Hansen et al, 1994]. The same study showed a clear excess of male breast cancer with a SMR of 7.0 (3 cases; 95% CI=1.5-21.4 ) [Hansen et al., 1994]. No association was observed in the investigation of female pharmacy technicians [Hansen and Olsen, 1994], or reported in the case-control studies [Habel et al., 1995; Coogan et al., 1996a].

    Radiation workers and x-ray technicians: Although ionizing radiation is a recognized risk factor for breast cancer [Committee on the Biological Effects of Ionizing Radiation, 1990], the low cumulative radiation doses experienced by x-ray technicians and atomic energy workers, the imprecision of measurements in most studies, the somewhat short follow-up and other confounders and biases could all explain the absence of positive findings so far.

    Excluded from consideration here were studies of the female radium dial painters because they have limited relevance to occupations post World War II. No descriptive study reported increased breast cancer risk among radiation workers and x-ray technicians. Seven cohort studies have presented results on radiation workers, including diagnostic x-ray personnel [Wang et al., 1988], workers at nuclear materials production plants [Hadjimichael et al., 1983; Loomis and Wolf, 1996], a thorium-processing plant [Liu et al., 1992], United Kingdom Atomic Energy Authority plants [Béral et al., 1985; Carpenter et al., 1994], the Sellafield reprocessing plant [Smith and Douglas, 1986], and United States nuclear plants [Vaughan et al., 1993; Kneale and Stewart, 1993; Frome et al., 1997]. These workers had experienced various exposure levels, and some of them had radiation to the whole body as well as exposure to radionuclides, usually at low doses. Only one of these occupational studies showed a statistically significant excess risk, among Chinese x-ray workers exposed for more than 20 years and who started working before 1950 [Wang et al., 1988]. However, most of the other studies were not powerful enough; two studies showed elevated risks: SIR=3.1 (3 cases; 95% CI=0.7-9.7) [Vaughan et al., 1993], SMR=1.21 (11 cases; 95% CI=0.60-2.17) [Loomis and Wolf, 1996]. A recent case-control study, conducted among female radiologic technologists in the U.S.A. [Boice et al, 1995; Morin Doody et al., 1995], did not show any increased risk of breast cancer in that population; their cumulative exposure was reported to be low. The two case-control studies designed for other purposes also did not find increased risks for these workers [Habel et al., 1995; Coogan et al., 1996a].

    General chemical exposures: Two descriptive studies showed increased risks of breast cancer among chemists [Hall and Rosenman, 1991; Morton, 1995]. Two cohort studies reported higher than expected risks among chemists, with considerably higher risks noted in single women (30 deaths; MOR=2.3, 95% CI=1.5-3.5) [Walrath et al., 1985], and a five-fold risk among 36 laboratory workers (7 deaths; MOR=5.3, 95% CI=2.8-10.1) [Dosemeci et al., 1992]. Cohort studies of female workers from three large chemical companies in the U.S.A. showed increased incidence in one with a SIR=1.33 (256 cases; p<0.05) among salaried employees [Pell et al., 1978; O'Berg et al., 1987], and non-significant increase of death in the two others with SMRs of 1.22 (46 cases; 95% CI=0.89-1.63) [Bond et al., 1987] and of 1.0 (39 cases; 95% CI=0.7-1.4) [Teta et al., 1990]. A small Italian cohort study of 505 chemical workers was also not conclusive for male breast cancer, but the authors underlined the low statistical power of their study [Rapiti et al., 1997].

    Specific chemical exposures have been investigated, with a lack of association reported for women exposed to chlorinated naphthalenes in the cable manufacturing industry (SMR=1.0, 95% CI=0.7-1.3) [Ward et al., 1994] and to formaldehyde [Blair et al., 1986; Stayner et al., 1988]. One cohort study of workers exposed to ethylene oxide obtained a SMR=0.8 (42 cases; 95% CI=0.6-1.1) [Steenland et al., 1991], whereas an incidence cohort study showed a two-fold increase in breast cancer incidence (8 to 12 cases; standardised morbidity ratio or SMbR=1.7 to 2.6, 95% CI=0.99-4.98, depending on the methods of calculation used) [Norman et al., 1995]. In a case-control study among members of the Kaiser Permanente Medical Care Program, a positive association (2507 cases; RR=1.53, 95% CI=1.00-2.33) was observed among women reporting occupational daily exposure (at least 2 hours) during the past year to engine exhaust [Van Den Eeden and Friedman, 1993].

    Rubber and plastics workers: Several cohort studies focusing on mortality have been published since the mid-seventies on rubber manufacturing workers, both female and male. Unfortunately, most of these studies investigated mortality only, and almost all of them had very little power to detect an increase in risk. None of these reported increased risks of breast cancer [Monson et al., 1976; Delzell and Monson, 1981; Andjelkovich et al., 1978; Gustavsson et al., 1986; Zhang et al., 1989; Sorahan and Pope, 1993b; Weiland et al., 1996]; Solionova and Smulevich [1993] reported a significant deficit of incidence of breast cancer in their cohort (8 cases; SIR=0.47, p<0.05). Finally, an Italian study presented elevated risks (2 deaths; non significant SMR= 1.86) among a cohort constituted by workers from 20 rubber and plastics factories [Ietri et al., 1997]. Mortality cohort studies of workers in polyvinyl fabrication [Chiazze et al., 1980], polyurethane foam manufacturing [Hagmar et al., 1993; Sorahan and Pope, 1993a; Schnorr et al., 1996], in cellulose fiber production [Lanes et al., 1990; Lanes et al., 1993; Gibbs et al., 1996] and in continuous filament fiberglass production [Watkins et al., 1997], did not report increased risks of breast cancer.

    Wood and pulp and paper: Of the four mortality cohort studies among workers in wood-related industries, three did not find an increased risk of female breast cancer [Jäppinen et al., 1989; Demers et al., 1995; Robinson et al., 1996], and one presented an elevated risk of 3.4 (4 deaths; 95% CI=0.9-8.8) among nonwhite women working in wood furniture plants [Miller et al., 1994]. An elevated PMR of 5.1 (4 cases; 95% CI=1.39-13.1) was found among wood products carpenters employed in the construction or wood products industries [Robinson et al., 1996]. One cohort study in the Spanish pulp and paper industry showed an elevated risk of female breast cancer of 2.84 (95% CI=0.77-7.32) based on 4 deaths [Sala-Serra et al., 1996], and two others showed a lower risks [Jäppinen et al., 1987; Coggon et al., 1997]. Again, most of the studies looked here at mortality from breast cancer.

    Organic solvents: Organic solvents are ubiquitous both in the environment and in the workplace. They take part in the manufacture of glues, paints, varnishes, various chemicals, and are used notably in dry cleaning and metal degreasing. A study on solvent exposure and mental disorders among males in Montreal showed that 57% of the control population had ever been exposed to organic solvents at work [Labrèche, 1989]. Many descriptive studies based on administrative records have suggested increased risks for certain occupations that may involve exposures to solvents, namely printing and publishing [Lynge & Thygesen, 1990; Hall & Rosenman, 1991; Aronson & Howe, 1994] and mechanics and repairers [Rubin et al., 1993]. No descriptive study of laundry and dry cleaning workers showed increased risks for female breast cancer [Katz and Jowett, 1981; Duh and Asal, 1984; Lynge and Thygesen, 1990; Walker et al., 1997], but one showed an increase of breast cancer among men aged 65 and over (4 deaths; PMR=12.75, 95% CI=3.47-32.63) [Walker et al., 1997].

    The analytic epidemiologic data are rather sparse (Table 3). The laundry and dry cleaning industry has used several organic solvents over the years. Stoddard solvent was used until the 1930s, followed by carbon tetrachloride, and then trichloroethylene, fluorocarbons, and tetrachloroethylene or perchloroethylene), the latter being the most prevalent nowadays [Brown and Kaplan, 1987; Blair et al., 1990]. The two available cohort studies, both focusing on mortality, were inconclusive for exposure to perchloroethylene [Brown and Kaplan, 1987; Ruder et al., 1994], or to a mixture of solvents, including Stoddard solvent, tetrachloroethylene, trichloroethylene, and fluorocarbons [Blair et al., 1990]. No case-control study showed increased risk for these workers.

    A mortality cohort study of aircraft maintenance workers exposed to trichloroethylene was consistent with the null results from the studies of dry cleaners [Spirtas et al., 1991]. An elevated risk was observed, however, among white women for exposure to isopropyl alcohol (number of cases not reported; SMR=3.12, 95% CI=1.25-6.43). Axelson and coworkers [1994] also investigated cancer incidence and mortality in trichloroethylene exposed workers, but they provided no risk estimate for cancer of the breast for males or females, and one assumes that very few cases were observed. Women employed in coiling and wire drawing in the manufacturing of light bulbs had an excess of breast cancer incidence among those who worked more than 5 years in the coiling and wire drawing department (8 cases; SIR=3.23, 95% CI=1.05-7.53) [Shannon et al., 1988]; methylene chloride and trichloroethylene were the two solvents used.

    One cohort study of female shoe manufacturers showed no increased risk of death from breast cancer [Paci et al., 1989], and three others did not present figures for breast cancer among their workers [Garabrant et al., 1984; Walker et al., 1993; Fu et al., 1996]. Two cohort studies of leather tannery workers showed risks between 20% and 50% above expected: in Sweden, Mikoczy and coworkers [1994] found incidence rates to be elevated for workers with at least 20 years since the first exposure (19 cases; SIR= 1.47, 95% CI=0.90-2.33), and in Italy, the mortality risks were at 1.25 (6 cases; 95% CI=0.46-2.73) [Montanaro et al., 1997]. No association for mortality was observed among styrene-exposed workers [Wong, 1990; Kogevinas et al., 1994; Wong et al., 1994], among a cohort of benzene-exposed Chinese women [Yin et al., 1996], among two cohorts of workers exposed to methylene chloride [Lanes et al., 1993; Gibbs et al., 1996], and among workers regularly monitored in Finland, for exposure to organic solvents [Anttila et al., 1995]. Danish printing workers had an increased incidence of female breast cancer (88 cases; SIR=1.35, 95% CI=1.08-1.66), especially among the bookbinders' assistants (48 cases; SIR=1.57, 95% CI=1.16-2.08) [Lynge et al., 1995]. A mortality follow-up study of oil refinery workers showed slightly higher risks among white women (20 cases; SMR=1.34, 95% CI=0.82-2.07) [Satin et al., 1996].

    Workers in the industries of newspaper printing (7 cases; SIR=3.9, p<0.01) and soap and perfume making (3 cases; SIR=7.6, p<0.05) had a higher risk of developing breast cancer in a Swedish case-control study [McLaughlin et al., 1988]. One case-control study reported a modest increase in incidence among females in the occupational group of painters, sculptors and printmakers (5 cases; RR=1.7, 95% CI=0.4-7.4) [Habet et al., 1995], and another one, a small increase among precision production occupations (128 cases; OR=1.26, 95% CI=0.98-1.62) [Coogan et al., 1996a].

    Physical exercise: Six case-control studies on female breast cancer applied ratings of physical activity to job titles information already collected: five of them reported a significant decreasing trend of breast cancer risk among women as they performed more active physical activities in their job [Vena et al., 1987; Vihko et al., 1992; Zheng et al., 1993; D'Avanzo et al., 1996; Coogan et al., 1997]; the last case-control study did not find any effect of increased physical activity on breast cacner risks [Dosemeci et al., 1993].

    Other occupations: Two other occupations have been associated to an increased risk among females: airline cabin attendants, in one record linkage cohort study (20 cases; SIR=1.87, 95% CI=1.15-2.23) [Pukkala et al., 1995], and professional artist painters in a proportional mortality study, based on 16 deaths (PMR=2.16, p< 0.01) [Miller and Blair, 1985]. Among males, the following occupations have been associated with elevated risks: the military service, with 16 cases on 52 compared to 6 controls on 52 serving in the military forces (p=0.06) [Mabuchi et al., 1985]; and Danish paper recycling workers with a non significantly increased incidence, based on 1 case (SIR= 2.63, 95% CI=0.03-14.64) [Andreassen Rix et al., 1997].

    Other exposures: In a case-control study of male breast cancer (52 cases and 52 controls), Mabuchi et al. [1985] found 7 male cases working in blast furnaces, steel works and rolling mills, whereas no control worked in such industries (p=0.016); they hypothesized a possible testicular effect of high environmental temperature to explain that finding. A small case-control study of male breast cancer found an elevated risk for heat-exposed jobs, based on 9 exposed cases (OR=2.3, 95% CI=0.95-5.3) [Rosenbaum et al., 1994]. Exposure to arsenic at a copper smelter was not related to an increased risk of death from male breast cancer in an American cohort study [Enterline et al., 1995].

    Discussion and recommendations

    Male and female breast cancers have very similar histopathologic features and share a few risk factors (such as age and family history of breast cancer in a first degree relative); mortality rates appear stable for both genders over the last 25 years [Sasco et al., 1993; National Cancer Institute of Canada, 1993]. However, their pattern of incidence differs in that it has not changed in males over the last decades, whereas it increased by 28% in Canadian females. This change of incidence among females together with their increased participation in the workplace, and the resulting different exposures, imply that causes may differ between genders or that at least changes in exposures have varied differently for males and females over the last decades.

    As stated earlier, we relied whenever possible on information from analytical (cohort and case-control) studies, that we considered to be more robust than the descriptive studies. But because few studies were designed specifically to investigate breast cancer risks, the limitations inherent in these studies must be recognized when interpreting the data. In particular, statistical power and risk estimates would have been reduced in mortality studies in which broad occupational groups were used as surrogates of exposure. As well, statistical power was generally quite low for assessing trends or for assessing risks in sub-groups. In addition, confounders were usually not taken into account in cohort studies and inference from these studies would be stronger if they had been controlled for.

    With regard to the assessment of exposure, one would expect in cohort studies that misclassification would be less pronounced than in studies using routinely collected data because job titles from plants should be more homogeneous for exposure. Nevertheless, exposures were ascertained in only a handful of studies. There were few cohort studies in which exposures were assessed directly or which analyses were conducted by job title. In the case-control studies, while detailed information regarding occupational lifetime histories were obtained directly from subjects, broad occupational groupings were reported in the analyses, but they had the advantage of adjusting for the major confounding factors.

    Selection into and out of work among subjects enrolled in cohort studies (i.e. the healthy worker effect) may also have led to underestimation of risks. It is difficult to control for these effects, although partial control of selection into the cohort can be achieved through the use of internal reference groups. However, no study reported such analyses for breast cancer, although they were carried out for other endpoints in a number of studies.

    It is clear from this review that few high quality studies directed specifically toward assessing occupational breast cancer risks, both among males and females, have been carried out to allow one to identify unambiguously occupational risk factors for breast cancer. The fact that the cohorts of women were generally small is understandable, as few women would have been working in hazardous employment during the period covered by many of these retrospective studies, even though women have been taking an increasingly active part in the workforce since World War II. The quality of studies has increased over the years, and the recent ones provide better adjusted figures. More detailed investigations are being carried out and more information is expected in the coming years.

    Future occupational studies should preferably focus on incidence data as the 5-year survival rates for breast cancer are around 75% [Pelletier, 1996]. They should rely as much as possible on histologically confirmed cases and even consider the estrogen and progesterone receptor status of the tumors, as recent studies have shown differing risk factors, treatment and prognostic features according to these tumor characteristics. Future studies should always take into account menopausal status for female breast cancers, as known risk factors are distributed differently for pre- and post-menopausal breast cancers and etiologic mechanisms could vary accordingly. More effort has to be put to refine the indicators of occupational exposures, e.g. job-exposure matrices, industrial hygiene measurements and estimates, and biological markers of exposure, and to design studies that allow for exposure-response analyses.

    As breast cancer is considered to be an hormone-related cancer and although many areas would benefit from more research, areas where workers are exposed to substances or circumstances susceptible to disrupt hormonal balance are probably among the most promising ones. Some examples are:

    - electromagnetic fields and night work (both affecting melatonin synthesis) could possibly exert a promoting effect; more effort should be put into quantifying the exposure levels and monitoring the size of the effect of these exposures (possibly using biomarkers such as melatonin);

    - organochlorines, pharmaceutical drugs and possibly some metals such as cadmium could indirectly increase the risk via estrogenic effects.

    As well, a few occupations entailing exposures that vary considerably within the same job title, e.g. nurses, chemical workers, etc., would be worth exploring in detail. Given the capacity of the breast, especially among women, to secrete fluids and accumulate xenobiotics, it would also be warranted to explore occupations with exposures to chemicals metabolised into reactive chemicals such as organic solvents and rubber and plastic chemicals [Labrèche and Goldberg, 1997].

    Table 1 Risks of breast cancer in relation to occupations with potential exposure to extremely low frequency electromagnetic fields



    Type of study

    Adjustment for risk factors

    Occupation / industry / exposure
    Cohort= power*/ Case-control = total number of cases
    Observed number of cases


    95% Confidence interval or p value
    Vågerö et al., 1985 Sweden Cohort (2047% / 867 &)
    Age and sex Telecommunication workers %: NA**

    &: 75.5%
    0 %

    7 &


    Matanoski et al., 1991 USA (1 State) Cohort (50,582 %)
    Age, dose of EMFs Telephone workers %: 2.5% 2 % SIR=6.5 0.79-23.5
    Tynes et al., 1992 Norway Cohort (37,945 %)
    Age Electrical workers (1961-85) %: 49.4% 12 % SIR=2.07 1.07-3.61
    Floderus et al., 1994 Sweden Cohort
    Age, dose of EMFs Railway workers (1961-69)
    Engine drivers (1961-69)
    %: 8.4%
    %: 5.4%
    4 cases
    3 cases
    Thériault et al., 1994 Québec, Ontario, France Cohort
    Case-control analysis
    Age Electric utility workers

    443 cancer cases

    7 cases


    Savitz & Loomis, 1995 5 places in the USA Cohort (138,905 %)
    Age Electric utility workers %: 63.7% 6 cases SMR=0.8 0.29-1.74
    Tynes et al., 1996 Norway Cohort (2,619 &)
    Case-control within cohort
    Age Female radio and telegraph operators on merchant ships
    >50 years old &
    > 3.2 years of employment
    Lot of shiftwork
    Lot of shiftwork before 30
    &: 99.7% 50 cases

    15 cases
    12 cases
    8 cases


    Demers et al., 1991 6 States + Detroit (MI), San Francisco (CA), Atlanta (GA), Seattle (WA) Case-control
    Age, Jewish religion,higher education, diagnostic x rays, serious head injury, Quetelet index Males probably exposed to EMFs (based on previously published list)
    Electric trades & related occupations
    227 breast cancers, 300 population controls 33 cases

    13 cases


    Loomis, 1992 USA, 24 States Case-control
    Age Electrical workers < 65 years
    Telephone workers
    250 % breast cancers 3 cases
    1 case
    Rosenbaum et al., 1994 New York State Case-control
    Age, race, marital status, address Occupations probably exposed to EMFs (based on previously published list) 63 % breast cancers 6 cases OR=0.7 0.3-1.9
    Habel et al., 1995 King County, WA Case-control
    Age, parity, education, alcohol intake, Quetelet index Telephone and other communication operators 536 breast cancers 22 cases OR=0.8 0.4-1.4
    Coogan et al., 1996b 4 States: Maine, Wisconsin, Massachusetts, New Hampshire Case-control, females
    Age, Quetelet index,benign breast disease, family history of breast cancer, age at menarche, parity, age at 1st birth, education, alcohol intake Occupations probably exposed to EMFs (based on previously published list)
    Pre-menopausal + high expo.

    Computer equipment operators (pre & post-menopausal)
    698 breast cancers probably exposed

    20 cases

    31 cases




    Stenlund & Floderus, 1997 Sweden Case-control, males
    Age, education, solvent exposure, family history of breast cancer, cryptorchidism Occupations probably exposed to EMF,

    # 60 years old, $0.41:T
    56 breast cancers

    4 cases

    3 cases





    * Power calculations were performed for a Poisson distribution, considering a detectable risk of 2, by George Tomlinson, PhD candidate, University of Toronto
    ** NA = Not applicable / NR: Not reported / SMR: Standardised mortality ratio / SIR: Standardised incidence ratio / RR=relative risk / OR=odds ratio

    Table 2. Risks of female breast cancer in relation to potential occupational exposure to pesticides and organochlorines



    Type of study

    Adjustment for risk factors

    Occupation / industry / exposure
    Cohort= power*/ Case-control = total number of cases Observed number of cases
    95% Confidence interval or p value
    Kogevinas et al., 1997 12 countries Cohort (20,851 % / 1,012 &) Age, country of residence Production, formulation and spraying of TCDD or higher chlorinated dioxins %: 7.3%

    &: 32.6%
    2 %

    9 &


    Kristensen et al., 1996 Norway Cohort (2,145 &, of which 590 farmers) Age, details on exposure Agricultural workers 100%

    598 &

    148 & farmers


    Pukkala & Notkola, 1997 Finland Cohort (106,162 % / 81,431 &) Age, type of farm Farmers %: 90.4%

    &: 100%
    11 %

    1,474 &


    Hansen et al., 1992 Denmark Cohort (3,156 % / 859 &) Age, type of work Gardeners %: NA

    &: 68.4%
    0 %

    10 &


    Folsom et al., 1996 Iowa Cohort Age, reproductive factors, lifestyle Women living on farms 100% 179 & RR=1.03 0.87-1.23
    Brown, 1987 New York, USA Cohort (1,318 &) Age Workers in electrical capacitor plants / PCBs 78.5% 9 & SMR=0.77 0.35-1.46
    Bertazzi et al., 1987 Italy Cohort (1,556 &) Age Electrical capacitor manufacturing workers / PCBs 20.9% 2 & SMR=1.01 0.11-3.63
    Coogan et al., 1996a 4 States: Maine, Wisconsin, Massachusetts, New Hampshire Case-control Age, reproductive factors, lifestyle Women employed in farming, forestry, fishing 6,835 cases 94 & OR=0.81 0.62-1.07
    Franceschi et al., 1993 Italy Case-control Age, reproductive factors, lifestyle, diet, etc. Farmers 132 cases 26 & OR=0.8 0.5-1.3

    * Power calculations were performed for a Poisson distribution, considering a detectable risk of 2, by George Tomlinson, PhD candidate, University of Toronto

    ** SMR: Standardised mortality ratio / SIR: Standardised incidence ratio / RR=relative risk / OR=odds ratio

    Table 3 Relative risks of breast cancer in occupations or industries with organic solvent exposure



    Type of study

    Adjustment for risk factors

    Occupation / industry / exposure
    Cohort= power*/ Case-control = total number of cases
    Observed number of cases


    95% Confidence interval or p value
    Chiazze et al., 1977, 1980 USA Cohort

    Polyvinylchloride fabricators Vinyl chloride NA 44 PMR=1.8 p> 0.05
    Stayner et al., 1985, 1988

    Garment industry Formaldehyde 100% 33 SMR=0.7 0.5-1.0
    Brown & Kaplan, 1987; Ruder et al., 1994 4 cities in California, Illinois, Michigan, New York Cohort

    Dry cleaning
    -Entire cohort
    -Tetrachloroethylene + other solvents (695)
    -Tetrachloroethylene (414)








    Shannon et al., 1988 Toronto, Ontario Cohort

    Lamp manufacturing Methylene chloride, trichloroethylene
    - Total cohort in coiling/ wire drawing (203)
    - 5 years work, 15 years latency








    Paci et al., 1989 Firenze, Italy Cohort

    Shoe manufacturing Benzene and other solvents 38.6% 4 SMR=0.9 0.2-2.3
    Blair et al., 1990 Missouri, USA Cohort

    Dry cleaners Tetrachloroethylene and other solvents 99.8% 36 SMR=1.0 0.7-1.4
    Wong et al., 1990, 1994 USA Cohort

    Reinforced plastics and composites industry Styrene 97.7% 14 SMR=0.6 0.3-1.1
    Spirtas et al., 1991 Utah, USA Cohort

    Aircraft maintenance
    -Mixed solvents
    -Isopropyl alcohol
    -Methylene chloride
    P2=6.2, p=0.01
    Lanes et al., 1993 South Carolina, USA Cohort

    Cellulose fiber production workers / Methylene chloride
    3 cases SMR=0.54 0.11-1.57
    Kogevinas et al., 1994 Denmark, Finland, Italy, Norway, Sweden, United Kingdom Cohort
    Mortality (6128)

    Styrene exposed workers 98.8% 13 SMR=0.5 0.3-0.9
    Mikoczy et al., 1994 Sweden Cohort

    Leather tanning: Benzene & other chlorinated solvents
    No latency period
    Latency 20 years




    Anttila et al., 1995 Finland Cohort

    Workers exposed to halogenated solvents Trichloroethylene,
    Tetrachloroethylene, 1,1,1-Trichloroethane
    99.9% 34 SIR=0.9 0.6-1.2
    Yin et al., 1996 China Chort
    (59,628 %,
    51,005 &)

    Benzene-exposed workers
    8 cases RR=0.9 0.3-3.2
    Montanaro et al., 1997 Genoa, Italy Cohort

    Tannery workers
    6 % & & SMR=1.25 0.46-2.73
    Habel et al., 1995 Washington State, USA Case control

    Painters, sculpters, printmakers Various solvents 537 cases &
    487 controls
    5 cases &
    3 controls
    RR=1.7 0.4-7.4
    Coogan et al., 1996a 4 States: Maine, Wisconsin, Massachusetts, New Hampshire Case-control

    Precision production workers
    128 cases OR=1.26 0.98-1.62

    * Power calculations were performed for a Poisson distribution, considering a detectable risk of 2, by George Tomlinson, PhD candidate, University of Toronto

    ** NA= Not applicable / NR: Not reported / SMR: Standardised mortality ratio / SIR: Standardised incidence raio / RR=relative risk / OR=odds ratio


    Adami HO, Lipworth L, Titus-Ernstoff L, Hsieh CC, Hanberg A, Ahlborg U, Baron J, Trichopoulos D. Organochlorine compounds and estrogen-related cancers in women. Cancer Causes Control 1995;6:551-66.

    Ad Hoc Committee on the Effect of Trace Anesthetics on the Health of Operating Room Personnel, American Society of Anesthesiologists. Occupational disease among operating room personnel: A national study. Anesthesiology 1974;41:321-40.

    Alavanja MCR, Akland G, Baird D, Blair A, Bond A, Dosemeci M, Kamel F, Lewis R, Lubin J, Lynch C, McMaster SB, Moore M, Pennybacker M, Ritz L, Rothman N, Rowland A, Sandler DP, Sinha R, Swanson C, Tarone R, Weinberg C, Hoar Zahm S. Cancer and noncancer risk to women in agriculture and pest control: the Agricultural Health Study. J Occup Med 1994;36:1247-50.

    Andjelkovich D, Taulbee J, Blum S. Mortality of female workers in a rubber manufacturing plant. J Occup Med 1978;20:409-13.

    Andreassen Rix B, Villadsen E, Engholm G, Lynge E. Risk of cancer among paper recycling workers. Occup Environ Med 1997;54:729-33.

    Aronson KJ, Howe GR. Utility of a surveillance system to detect associations between work and cancer among women in Canada, 1965-1991. J Occup Med 1994;36:1174-9.

    Austin SG, Huang N, Woernle CW. PMR study of mortality among Alabama workers and farmers. Am J Ind Med 1995; 27: 29-36.

    Axelson O, Seldén A, Andersson K, Hogstedt C. Updated and expanded Swedish cohort study of trichloroethylene and cancer risk. J Occup Med 1994;36:556-62.

    Belli S, Comba P, De Santis M, Grignoli M, Sasco AJ. Mortality study of workers by the Italian National Institute of Health, 1960-89. Scand J Work Environ Health 1992;18:64-7.

    Beral V, Inskip H, Fraser P, Booth M, Coleman D,Rose G. Mortality of employees of the United Kingdom Atomic Energy Authority, 1946-1979. Br Med J 1985;291:440-7.

    Bertazzi PA, Riboldi L, Pesatori A, Radice L, Zocchetti C. Cancer mortality of capacitor manufacturing workers. Am J Ind Med 1987;11:165-76.

    Blair A, Dosemeci M, Heineman EF. Cancer and other causes of death among male and female farmers from twenty-three states. Am J Ind Med 1993; 23:729-42.

    Blair A, Stewart P, O'Berg M, Gaffey W, Walrath J, Ward J, et al. Mortality among industrial workers exposed to formaldehyde. J Natl Cancer Inst 1986;76:1071-84.

    Blair A, Stewart PA, Tolbert PE, Grauman D, Moran FX, Vaught J, Rayner J. Cancer and other causes of death among a cohort of dry cleaners. Br J Ind Med 1990;47:162-8.

    Boice JD, Mandel JS, Morin Doody M. Breast cancer among radiologic technologists. J A M A 1995;274:394-401.

    Bond GG, McLaren EA, Cartmill JB, Wymer KT, Lipps TE, Cook RR. Mortality among female employees of a chemical company. Am J Ind Med 1987;12:563-78.

    Brown DP. Mortality of workers exposed to polychlorinated biphenyls - An update. Arch Environ Health 1987;42:333-9.

    Brown DP, Jones M. Mortality and industrial hygiene study of workers exposed to polychlorinated biphenyls. Arch Environ Health 1981;36:120-9.

    Brown DP, Kaplan SD. Retrospective cohort mortality study of dry cleaner workers using perchloroethylene. J Occup Med 1987;29:535-40.

    Bulbulyan M, Zahm SH, Zaridze DG. Occupational cancer mortality among urban women in the former USSR. Cancer Causes Control 1992;3:299-307.

    Cantor KP, Dosemeci M, Brinton LA, Stewart PA. Re: Breast cancer mortality among female electrical workers in the United States. J Natl Cancer Inst 1995;87:227-8.

    Carpenter L, Higgins C, Douglas A, Fraser P, Beral V, Smith P. Combined analysis of mortality in three United Kingdom nuclear industry workforces, 1946-1988. Radiat Res 1994;138:224-38.

    Chiazze L, Wong O, Nichols WE, Ference LD. Breast cancer mortality among PVC fabricators. J Occup Med 1980;22:677-9.

    Coggon D, Wield G, Pannett B, Campbell L, Boffetta P. Mortality of employees of a Scottish paper mill. Am J Ind Med 1997;32:535-9.

    Cohen EN, Brown BW, Bruce DL, Cascorbi HF, Corbett TH, Jones TW, Whitcher CE. Occupational disease among operating room personnel. Anesthesiol 1974;41:321-40.

    Cohen EN, Brown BW, Wu ML, Whitcher CE, Brodsky JB, Gift HC, Greenfield W, Jones TW, Driscoll EJ. Occupational disease in dentistry and chronic exposure to trace anesthetic gases. J Am Dental Assoc 1980;101:21-31.

    Coleman MP, Estève J, Damiecki P, Arslan A, Renard H. Breast (females) In: Trends in cancer incidence and mortality. Lyon, France: International Agency for Research on Cancer. IARC Sci. Pub No 121. 1993:411-432.

    Committee on the Biological effects of Ionizing Radiation, National Research Council. Health Effects of Exposure to Low Levels of Ionizing Radiation. Washington, DC: U.S. National Academy Press, 1990.

    Coogan PF, Clapp RW, Newcomb PA, Mittendorf R, Bogdan G, Baron JA, Longnecker MP. Variation in female breast cancer risk by occupation. Am J Ind Med 1996a;30:430-7.

    Coogan PF, Clapp RW, Newcomb PA, Wenzl TB, Bogdan G, Mittendorf R, Baron JA, Longnecker MP. Epidemiology 1996b;7:459-64.

    Coogan PF, Newcomb PA, Clapp RW, Trentham-Dietz A, Baron JA, Longnecker MP. Physical activity in usual occupation and risk of breast cancer (United States). Cancer Causes Control 1997;8:626-31.

    Corbett TH, Cornell RG, Lieding K, Endres JL. Incidence of cancer among Michigan nurse-anesthetists. Anesthesiol 1973;38:260-3.

    D'Avanzo B, Nanni O, La Vecchia C, Franceschi s, Negri E, Giacosa A, Conti E, Montella M, Talamini R, Decarli A. Physical activity and breast cancer risk. Cancer Epidemiol Biomarkers Prev 1996;5:155-60.

    Decouflé P, Stanislawczyk K, Houten L, Bross IDJ, Viadana E. A retrospective survey of cancer in relation to occupation. Cincinnati, OH: National Institute for Occupatioanl Safety and Health, 1977. (NIOSH publication 77-178.)

    Decouflé P, Walrath J. Proportionate mortality among US shoeworkers, 1966-77. Am J Ind Med 1983;4:523-32.

    Delzell E, Beall C, Macaluso M. Cancer mortality among women employed in motor vehicle manufacturing. J Occup Med 1994;36:1251-9.

    Delzell E, Grufferman S. Cancer and other causes of death among female textile workers 1976-78. J Natl Cancer Inst 1983; 71:735-740

    Delzell E, Monson RR. Mortality among rubber workers. III. Cause-specific mortality, 1940-78. J Occup Med 1981;23:677-84.

    Demers PA, Boffetta P, Kogevinas M, Blair A, Miller BA, Robinson CF, Roscoe RJ, Winter PD, Colin D, Matos E, Vainio H. Pooled reanalysis of cancer mortality among five cohorts of workers in wood-related industries. Scand J Work Environ Health 1995;21:179-90.

    Demers PA, Thomas DB, Rosenblatt KA, Jimenez LM, McTiernan A, Stalsberg H. Occupational exposure to electromagnetic fields and breast cancer in men. Am J Epidemiol 1991; 134:340-7.

    Dewailly E, Dodin S, Verreault R, Ayotte P, Sauvé L, Morin J, Brisson J. High organochlorine body burden in women with estrogen receptor-positive breast cancer. J Natl Cancer Inst 1994;86:232-234.

    Doebbert G, Riedmiller KR, Kizer KW. Occupational mortality of California women, 1979-1981. West J Med 1988;149:734-40.

    Doll R, Peto R. The causes of cancer. J Natl Cancer Inst 1981; 66:1197-1312.

    Dosemeci M, Alavanja M, Vetter R, Eaton B, Blair A. Mortality among laboratory workers employed at the US Department of Agriculture. Epidemiology 1992; 3:258-62.

    Dosemeci M, Blair A. Occupational cancer mortality among women employed in the telephone industry. J Occup Med 1994;36:1204-9.

    Dosemeci M, Hayes RB, Vetter R, Hoover RN, Tucker M, Engin K, Unsal M, Blair A. Occupational physical activity, socioeconomic status, and risks of 15 cancer sites in Turkey. Cancer Causes Control 1993;4:313-21.

    Dubrow R, Gute DM. Cause-specific mortality among Rhode Island jewelry workers. Am J Ind Med 1987;12:579-93.

    Duh RW, Asal NR. Mortality among laundry and dry cleaning workers in Oklahoma. Am J Public Health 1984;74:1278-80.

    Eisen EA, Tolbert PE, Monson RR, Smith TJ. Mortality studies of machining fluid exposure in the automobile industry. I: A standardized mortality ratio analysis. Am J Ind Med 1992;22:809-24.

    Enterline PE, Day R, Marsh GM. Cancers related to exposure to arsenic at a copper smelter. Occup Environ Med 1995;52:28-32.

    Falck F Jr, Ricci A Jr, Wolff MS, Godbold J, Deckers P. Pesticides and polychlorinated biphenyl residues in human breast lipids and their relation to breast cancer. Arch Environ Health 1992;47:143-6.

    Floderus B, Törnqvist S, Stenlund C. Incidence of selected cancers in Swedish railway workers, 1961-79. Cancer Causes Control 1994;5:189-94.

    Folsom AR, Zhang S, Sellers TA, Zheng W, Kushi LH, Cerhan JR. Cancer incidence among women living on farms: findings from the Iowa Women's Health Study. J Occup Environ Health 1996;38:1171-6.

    Franceschi S, Barbone F, Bidoli E, Guarneri S, Serraino D, Talamini R, La Vecchia C. Cancer risk in farmers: results from a multi-site case-control study in north-eastern Italy. Int J Cancer 1993;53:740-5.

    Frome EL, Cragle DL, Watkins JP, Wing S, Shy CM, Tankersley WG, West CM A mortality study of employees of the nuclear industry in Oak Ridge, Tennessee. Radiat Res 1997; 148: 64-80.

    Fu H, Demers PA, Seniori Costantini A, Winter P, Colin D, Kogevinas M, Boffetta P. Cancer mortality among shoe manufacturing workers: an analysis of two cohorts. Occup Environ Med 1996;53:394-8.

    Garabrant DH, Wegman DH. Cancer mortality among shoe and leather workers in Massachusetts. Am J Ind Med 1984; 5:303-14.

    Gibbs GW, Amsel J, Soden K. A cohort mortality study of cellulose triacetate-fiber workers exposed to methylene chloride. J Occup Environ Med 1996;38:693-7.

    Goldberg MS, Labrèche F. Occupational risk factors for female breast cancer. Occup Environ Med 1996;53:145-56.

    Goldberg MS, Thériault G. Retrospective cohort study of workers of a synthetic textiles plant in Quebec: I. General mortality. Am J Ind Med 1994; 25:889-907.

    Gubéran E, Raymond L, Sweetnam PM. Increased risk for male bladder cancer among a cohort of male and female hairdressers from Geneva. Int J Epidemiol 1985;14:549-54.

    Guénel P, Raskmark P, Bach Andersen J, Lynge E. Incidence of cancer in persons with occupational exposure to electromagnetic fields in Denmark. Br J Ind Med 1993;50:758-64.

    Gunnarsdóttir H, Rafnsson V. Cancer incidence among Icelandic nurses. J Occup Environ Med 1995;37:307-12.

    Gustavsson P, Hogstedt C, Holmberg B. Mortality and incidence of cancer among Swedish rubber workers, 1952-1981. Scand J Work Environ Health 1986;12:538-44.

    Habel LA, Stanford JL, Vaughan TL, Rossing MA, Voigt LF, Weiss NS, Daling JR. Occupation and breast cancer risk in middle-aged women. J Occup Environ Med 1995;37:349-56.

    Hadjimichael OC, Ostfeld AM, D'Atri DA, Brubaker RE. Mortality and cancer incidence experience of employees in a nuclear fuels fabrication plant. J Occup Med 1983;25:48-61.

    Hagmar L, Welinder H, Mikoczy Z. Cancer incidence and mortality in the Swedish polyurethane foam manufacturing industry. Br J Ind Med 1993;50:537-43.

    Hall A, Harrington JM, Aw TC. Mortality study of British pathologists. Am J Ind Med 1991;20:83-9.

    Hall NEL, Rosenman KD. Cancer by industry: Analysis of a population-based cancer registry with an emphasis on blue-collar workers. Am J Ind Med 1991;19:145-59.

    Hansen ES, Hasle H, Lander F. A cohort study on cancer incidence among Danish gardeners. Am J Ind Med 1992;21:651-60.

    Hansen J, Olsen JH, Larsen AI. Cancer morbidity among employees in a Danish pharmaceutical plant. Int J Epidemiol 1994;23:891-8.

    Hansen J, Olsen JH. Cancer morbidity among Danish female pharmacy technicians. Scand J Work Environ Health 1994;20:22-6.

    Harrington JM, Goldblatt P. Census based mortality study of pharmaceutical industry workers. Br J Ind Med 1986;43:206-11.

    Hayes RB, Dosemeci M, Riscigno M, Blair A. Cancer mortality among jewelry workers. Am J Ind Med 1993;24:743-51.

    Holford TR, Roush GC, McKay LA. Trends in female breast cancer in Connecticut and the United States. J Clin Epidemiol 1991;44:29-39.

    Hunter DJ, Colditz GA, Stampfer MJ, Rosner B, Willett WC, Speizer FE. Risk factors for basal cell carcinoma in a prospective cohort of women. Ann Epidemiol 1990;1:13-23.

    Hunter DJ, Hankinson SE, Laden F, Colditz GA, Manson JAE, Willett WC, Speizer FE, Wolf MS. Plasma organochlorine levels and the risk of breast cancer. New Engl J Med 1997; 337: 1253-8.

    IARC. Occupational exposures of hairdressers and barbers and personal use of hair colourants; some hair dyes, cosmetic colourants, industrial dyestuffs and aromatic amines. Vol 57. IARC Monographs on the evaluation of carcinogenic risks to humans. Lyon, France: IARC, WHO, 1993.

    Ietri E, Belli S, Comba P, Gerosa A, Raffi GB, Pirastu RM. Cohort mortality study of rubber and plastics product makers in Italy. Occup Med 1997;47:417-22.

    Jäppinen P, Hakulinen T, Pukkala E, Tola S, Kurppa K. Cancer incidence of workers in the Finnish pulp and paper industry. Scand J Work Environ Health 1987;13:197-202.

    Jäppinen P, Pukkala E, Tola S. Cancer incidence of workers in a Finnish sawmill. Scand J Work Environ Health 1989;15:18-23.

    Kato I, Tominaga S, Ikari A. An epidemiological study on occupation and cancer risk. Jpn J Clin Oncol 1990;20:121-7.

    Katz RM, Jowett D. Female laundry and dry cleaning workers in Wisconsin: A mortality analysis. Am J Public Health 1981; 71:305-7.

    Katz RM. Causes of death among registered nurses. J Occup Med 1983;25:760-2.

    Kelsey JL. Breast cancer epidemiology: Summary and future directions. Epidemiol Rev 1993;15:256-63.

    King AS, Threlfall WJ, Band PR, Gallagher RP. Mortality among female registered nurses and school teachers in British Columbia. Am J Ind Med 1994; 26:125-32.

    Kneale GW, Stewart AM. Reanalysis of Hanford data: 1944-1986 deaths. Am J Ind Med 1993;23:371-89.

    Koenig KL, Pasternack BS, Shore RE, Strax P. Hair dye use and breast cancer: A case-control study among screening participants. Am J Epidemiol 1991; 133:985-95.

    Kogevinas M, Becher H, Benn T, Bertazzi PA, Boffetta P, Bueno-de-Mesquita HB, Coggon D, Colin D, Flesch-Janys D, Fingerhut M, Green L, Kauppinen T, Littorin M, Lynge E, Mathews JD, Neuberger M, Pearce N, Saracci R. Cancer mortality in workers exposed to phenoxy herbicides, chlorophenols, and dioxins. Am J Epidemiol 1997;145:1061-75.

    Kogevinas M, Ferro G, Andersen A, Bellander T, Biocca M, Coggon D. Cancer mortality in a historical cohort study of workers exposed to styrene. Scand J Work Environ Health 1994;20:251-61.

    Kono S, Tokudome S, Ikeda M, Yoshimura T, Kuratsune M. Cancer and other causes of death among female beauticians. J Natl Cancer Inst 1983;70:443-6.

    Krieger N, Wolff MS, Hiatt RA, Rivera M, Vogelman J, Orentreich N. Breast cancer and serum organochlorines: a prospective study among white, black, and asian women. J Natl Cancer Inst 1994;86:589-599.

    Kristensen P, Andersen A, Irgens LM, Laake P, Bye AS. Incidence and risk factors of cancer among men and women in Norwegian agriculture. Scand J Work Environ Health 1996;22:14-26.

    Labrèche F. Occupational solvent exposure and mental disorders. PhD Thesis submitted to McGill University, Montreal. 1989:76.

    Labrèche FP, Goldberg MS. Exposure to organic solvents and breast cancer: A hypothesis. Am J Ind Med 1997; 32: 1-14.

    Lanes SF, Cohen A, Rothman KJ, Dreyer NA, Soden KJ. Mortality of cellulose fiber production workers. Scand J Work Environ Health 1990;16:247-51.

    Lanes SF, Rothman KJ, Dreyer NA, Soden KJ. Mortality of cellulose fiber production workers. Scand J Work Environ Health 1993;19:426-8.

    Littorin M, Attewell R, Skerfving S, Horstmann V, Möller T. Mortality and tumour morbidity among Swedish market gardeners and orchardists. Int Arch Occup Environ Health 1993;65:163-9.

    Liu Z, Lee T-S, Kotek TJ. Mortality among workers in a thorium-processing plant - A second follow-up. Scand J Work Environ Health 1992;18:162-8.

    Loomis DP. Cancer of breast among men in electrical occupations. Lancet 1992; 339:1482-3.

    Loomis DP, Browning SR, Schenk AP, Gregory E, Savitz DA. Cancer mortality among electric utility workers exposed to polychlorinated biphenyls. Occup Environ Med 1997;54:720-8.

    Loomis DP, Savitz DA, Ananth CV. Breast cancer mortality among female electrical workers in the United States. J Natl Cancer Inst 1994;86:921-5.

    Loomis DP, Wolf SH. Mortality of workers at a nuclear materials production plant at Oak Ridge, Tennessee, 1947-1990. Am J Ind Med 1996; 29: 131-41.

    Lopez-Carrillo L, Blair A, Lopez-Cervantes M, Cebrian M, Rueda C, Reyes R, Mohar A, Bravo J. Dichlorodiphenyltrichloroethane serum levels and breast cancer risk: a case-control study from Mexico. Cancer Res 1997;57:3728-32.

    Lynge E, Thygesen L. Occupational cancer in Denmark. Cancer incidence in the 1970 census population. Scand J Work Environ Health 1990; 16(Suppl 2):7-35.

    Lynge E, Thygesen L. Primary liver cancer among women in laundry and dry-cleaning work in Denmark. Scand J Work Environ Health 1990;16:108-12.

    Madigan MP, Ziegler RG, Benichou J, Byrne C, Hoover RN. Proportion of breast cancer cases in the United States explained by well-established risk factors. J Natl Cancer Inst 1995;87:1681-5.

    Malker HSR, Gemne G. A register-epidemiology study on cancer among Swedish printing industry workers. Arch Environ Health 1987;42:73-82.

    Matanoski GM, Breysse PN, Elliott EA. Electromagnetic field exposure and male breast cancer. Lancet 1991; 337:737.

    McDonald JC, Liddell FDK, Gibbs GW, Eyssen GE, McDonald AD. Dust exposure and mortality in chrysotile mining, 1910-75. Br J Ind Med 1980;37:11-24.

    Menck HR, Pike MC, Henderson BE, Jing JS. Lung cancer risk among beauticians and other female workers: brief communication. J Natl Cancer Inst 1977;59:1423-5.

    Merchant JA, Ortmeyer C. Mortality of employees of two cotton mills in North Carolina. Chest 1981; 79:6S-11S

    Mikoczy Z, Schütz A, Hagmar L. Cancer incidence and mortality among Swedish leather tanners. Occup Environ Med 1994;51:530-5.

    Milham S Jr. Occupational mortality in Washington State 1950-1979. Cincinnati, OH: U.S. Dept of Health and Human Services, Centres for Diseases Control, National Institute for Occupational Safety and Health, 1983. (DHHS NIOSH) publication no. 83-116.)

    Miller BA, Blair A, McCann M. Mortality patterns among professional artists: A preliminary report. J Environ Pathol 1985;6:303-13.

    Miller BA, Blair A, Reed EJ. Extended mortality follow-up among men and women in a U.S. furniture workers union. Am J Ind Med 1994;25:537-49.

    Monson RR, Nakano KK. Mortality among rubber workers. II. Other employees. Am J Epidemiol 1976;103:297-303.

    Montanaro F, Ceppi M, Demers PA, Puntoni R, Bonassi S. Mortality in a cohort of tannery workers. Occup Environ Med 1997;54:588-91.

    Morin Doody M, Mandel JS, Boice JD. Employment practices and breast cancer among radiologic technologists. J Occup Environ Med 1995;37:321-7.

    Morton WE. Major differences in breast cancer risks among occupations. J Occup Environ Med 1995;37:328-35.

    National Cancer Institute of Canada. Canadian Cancer Statistics 1993. Toronto: National Cancer Institute of Canada, 1993.

    National Cancer Institute of Canada. Canadian Cancer Statistics 1997. Toronto: National Cancer Institute of Canada, 1997.

    Newhouse ML, Berry G, Wagner JC, Turok ME. A study of the mortality of female asbestos workers. Brit J Ind Med 1972;29:134-41.

    Newhouse ML, Berry G, Wagner JC. Mortality of factory workers in East London 1933-80. Br J Ind Med 1985;42:4-11.

    Norman SA, Berlin JA, Soper KA, Middendorf BF, Stolley PD. Cancer incidence in a group of workers potentially exposed to ethylene oxide. Int J Epidemiol 1995; 24: 276-84.

    O'Berg MT, Burke CA, Chen JL, Walrath J, Pell S, Gallie CR. Cancer incidence and mortality in the Du Pont Company: an update. J Occup Med 1987;29:245-52.

    Olsen JH, Jensen OM. Occupation and risk of cancer in Denmark. An analysis of 93810 cancer cases, 1970-1979. Scand J Work Environ Health 1987;13:(Suppl 1); 91p.

    Paci E, Buiatti E, Seniori Costantini A, Miligi L, Pucci N, Scarpelli A. Aplastic anemia, leukemia and other cancer mortality in a cohort of shoe workers exposed to benzene. Scand J Work Environ Health 1989;15:313-8.

    Park RM, Wegman DH, Silverstein MA, Maizlish NA, Mirer FE. Causes of death among workers in a bearing manufacturing plant. Am J Ind Med 1988;13:569-80.

    Parkin DM, Muir CS, Whelan SL, Gao YT, Ferlay J, Powell (eds) Cancer incidence in five continents. Volume IV. Lyon, France: IARC, International Association of Cancer Registries, WHO (IARC Publ. No. 120). 1992 pp. 243-99.

    Pell S, O'Berg MT, Karrh BW. Cancer epidemiologic surveillance in the Du Pont Company. J Occup Med 1978;20:725-40.

    Pelletier G. La survie reliée au cancer: le Québec comparé. No. 32, Coll Données statistiques et indicateurs. MSSS, Direction générale de la planification et de l'évaluation. 1996.

    Peto J, Doll R, Howard SV, Kinlen LJ, Lewinson HC. A mortality study among workers in an English asbestos factory. Br J Ind Med 1977;34:169-73.

    Pukkala E, Auvinen A, Wahlberg G. Incidence of cancer among Finnish airline cabin attendants, 1967-92. Br Med J 1995;311:649-52.

    Pukkala E, Nokso-Koivisto P, Roponen P. Changing cancer risk pattern among Finnish hairdressers. Int Arch Occup Environ Health 1992;64:39-42.

    Pukkala E, Notkola V. Cancer incidence among Finnish farmers, 1979-93. Cancer Causes Control 1997;8:25-33.

    Rapiti E, Fantini F, Dell'Orco V, Fano V, Blasetti F, Bracci C, Forastiere F, Comba P. Cancer mortality among chemical workers in an Italian plant. Eur J Epidemiol 1997;13:281-5.

    Robinson CF, Petersen M, Sieber WK, Palu S, Halperin WE. Mortality of carpenters' union members employed in the U.S. construction or wood products industries, 1987-90. Am J Ind Med 1996;30:674-94.

    Roman E, Beral V, Inskip H. Occupational mortality among women in England and Wales. Br Med J 1985;291:194-6.

    Ronco G, Costa G, Lynge E. Cancer risk among Danish and Italian farmers. Br J Ind Med 1992;49:220-5.

    Rosenbaum PF, Vena JE, Zielezny MA, Michalek AM. Occupational exposures associated with male breast cancer. Am J Epidemiol 1994;139:30-6.

    Rotimi C, Austin H, Delzell E, Day C, Macaluso M, Honda Y. Retrospective follow-up study of foundry and engine plant workers. Am J Ind Med 1993;24:485-98.

    Rubin CH, Burnett CA, Halperin WE, Seligman PJ. Occupation as a risk identifier for breast cancer. Am J Public Health 1993;83:1311-5.

    Ruder AM, Ward EM, Brown DP. Cancer mortality in female and male dry-cleaning workers. J Occup Med 1994;36:867-74.

    Sala-Serra M, Sunyer J, Kogevinas M, McFarlane D, Antó JM. Cohort study on cancer mortality among workers in the pulp and paper industry in Catalonia, Spain. Am J Ind Med 1996;30:87-92.

    Sankila R, Karjalainen S, Läärä E, Pukkala E, Teppo L. Cancer risk among health care personnel in Finland, 1971-1980. Scand J Work Environ Health 1990;16:252-7.

    Saracci R, Simonato L, Acheson ED, Andersen A, Bertazzi PA, Claude J. Mortality and incidence of cancer of workers in the man made vitreous fibres producing industry: an international investigation at 13 European plants. Br J Ind Med 1984;41:425-36.

    Sasco AJ, Lowenfels AB, Pasker-de Jong P. Review article: Epidemiology of male breast cancer. A meta-analysis of published case-control studies and discussion of selected aetiological factors. Int J Cancer 1993;53:538-49.

    Satin KP, Wong O, Yuan LA, Bailey WJ, Newton KL, Wen CP, Swencicki RE. A 50-year mortality follow-up of a large cohort of oil refinery workers in Texas. J Occup Environ Med 1996;38:492-506.

    Savitz DA, Loomis DP. Magnetic field exposure in relation to leukemia and brain cancer mortality among electric utility workers. Am J Epidemiol 1995;141:123-34.

    Schnatter R, Thériault G, Katz AM, Thompson FS, Donaleski D, Murray N. A retrospective mortality study within operating segments of a petroleum company. Am J Ind Med 1992;22:209-29.

    Schnorr TM, Steenland K, Egeland GM, Boeniger M, Egilman D. Mortality of workers exposed to toluene diisocyanate in the polyurethane foam industry. Occup Environ Med 1996;53:703-7.

    Seidman H, Stellman SD, Mushinski MH. A different perspective on breast cancer risk factors: some implications of the nonattributable risk. CA: Cancer J Clin 1982;32:301-13.

    Seniori Costantini A, Pirastu R, Lagorio S, Miligi L, Costa G. Studying cancer among female workers: Methods and preliminary results from a record-linkage system in Italy. J Occup Med 1994;36:1180-6.

    Shannon HS, Haines T, Bernholz C, Julian JA, Verma DK, Jamieson E, Walsh C. Cancer morbidity in lamp manufacturing workers. Am J Ind Med 1988;14:281-90.

    Shannon HS, Jamieson E, Julian JA, Muir DCF. Mortality of glass filament (textile) workers. Br J Ind Med 1990;47:533-6.

    Shindell S, Ulrich S. Mortality of workers employed in the manufacture of chlordane: An update. J Occup Med 1986;28:497-501.

    Silverstein M, Mirer F, Kotelchuck D, Silverstein B, Bennett M. Mortality among workers in a die-casting and electroplating plant. Scand J Work Environ Health 1981;7(Suppl 4):156-65.

    Simonato L, Fletcher AC, Cherrie J, Andersen A, Bertazzi PA, Charnay N. The man-made mineral fiber European historical cohort study. Extension of the follow-up. Scand J Work Environ Health 1986;12(suppl 1):34-47.

    Smith PG, Douglas AJ. Mortality of workers at the Sellafield plant of British Nuclear Fuels. Br Med J 1986;293:845-54.

    Smulevich VB, Fedotova IV, Filatova VS. Increasing evidence of the rise of cancer in workers exposed to vinylchloride. Br J Ind Med 1988;45:93-7.

    Solionova LG, Smulevich VB. Mortality and cancer incidence in a cohort of rubber workers in Moscow. Scand J Work Environ Health 1993;19:96-101.

    Sorahan T, Burges DCL, Waterhouse JAH. A mortality study of nickel/chromium platers. Br J Ind Med 1987;44:250-8.

    Sorahan T, Pope D. Mortality and cancer morbidity of production workers in the United Kingdom flexible polyurethane foam industry. Br J Ind Med 1993a;50:528-36.

    Sorahan T, Pope D. Mortality study of workers employed at a plant manufacturing chemicals for the rubber industry: 1955-86. Br J Ind Med 1993b;50:998-1002.

    Sorahan T, Pope DJ, McKiernan MJ. Cancer incidence and cancer mortality in a cohort of semiconductor workers: an update. Br J Ind Med 1992;49:215-6.

    Sorahan T, Waterhouse JAH, McKiernan MJ, Aston RHR. Cancer incidence and cancer mortality in a cohort of semiconductor workers. Br J Ind Med 1985;42:546-50.

    Spinelli JJ, Gallagher RP, Band PR, Threlfall WJ. Multiple myeloma, leukemia, and cancer of the ovary in cosmetologists and hairdressers. Am J Ind Med 1984; 6:97-102.

    Spirtas R, Stewart PA, Lee JS, Marano DE, Forbes CD, Grauman DJ. Retrospective cohort mortality study of workers at an aircraft maintenance facility. I. Epidemiological results. Br J Ind Med 1991;48:515-30.

    Stayner L, Smith AB, Reeve G, Blade L, Elliott L, Keenlyside R, Halperin W. Proportionate mortality study of workers in the garment industry exposed to formaldehyde. Am J Ind Med 1985;7:229-40.

    Stayner LT, Elliott L, Blade L, Keenlyside R, Halperin W. A retrospective cohort mortality study of workers exposed to formaldehyde in the garment industry. Am J Ind Med 1988;13:667-81.

    Steenland K, Stayner L, Greife A, Halperin W, Hayes R, Hornung R, Newlin S. Mortality among workers exposed to ethylene oxide. N Engl J Med 1991;324:1402-7.

    Stenlund C, Floderus B. Occupational exposure to magnetic fields in relation to male breast cancer: a Swedish case-control study. Cancer Causes Control 1997;8:184-91.

    Stevens RG. Electric power use and breast cancer: a hypothesis. Am J Epidemiol 1987;125:556-61.

    Stevens RG, Davis S, Thomas DB, Anderson LE, Wilson BW. Electric power, pineal function, and the risk of breast cancer. FASEB J 1992;6:853-60.

    Stevens RG, Moolgavkar SH, Lee JAH. Temporal trends in breast cancer. Am J Epidemiol 1982;115:759-77.

    Stubbs HA, Harris J, Spear RC. A proportionate mortality analysis of California agricultural workers, 1978-79. Am J Ind Med 1984;6:305-20.

    Teta MJ, Schnatter AR, Ott MG, Pell S. Mortality surveillance in a large chemical company: The Union Carbide Corporation experience, 1974-1983. Am J Ind Med 1990;17:435-47.

    Teta MJ, Walrath J, Meigs JW, Flannery JT. Cancer incidence among cosmetologists. J Natl Cancer Inst 1984; 72:1051-7.

    Thériault G, Goldberg M, Miller AB, Armstrong B, Guénel P, Deadman J, Imbernon E, To T, Chevalier A, Cyr D, Wall C. Cancer risks associated with occupational exposure to magnetic fields among electric utility workers in Ontario and Quebec, Canada, and France: 1970-1989. Am J Epidemiol 1994;139:550-72.

    Thomas DB. Breast cancer in men. Epidemiol Rev 1993;15:220-31.

    Thomas TL. A preliminary investigation of mortality among workers in the pottery industry. Int J Epidemiol 1982;11:175-80.

    Thomas TL, Decoufle P. Mortality among workers employed in the pharmaceutical industry: A preliminary investigation. J Occup Med 1979;21:619-23.

    Threlfall WJ, Gallagher RP, Spinelli JJ, Band PR. Reproductive variables as possible confounders in occupational studies of breast and ovarian cancer in females. J Occup Med 1985;27:448-50.

    Trichopolous D. Are electric or magnetic fields affecting mortality from breast cancer in women? (Editorial) J Natl Cancer Inst 1994;86:885-6.

    Tynes T, Andersen A. Electromagnetic fields and male breast cancer. Lancet 1990;336:1596.

    Tynes T, Andersen A, Langmark F. Incidence of cancer in Norwegian workers potentially exposed to electromagnetic fields. Am J Epidemiol 1992; 136:81-8.

    Tynes T, Hannevik M, Andersen A, Vistnes AI, Haldorsen T. Incidence of breast cancer in Norwegian female radio and telegraph operators. Cancer Causes Control 1996;7:197-204.

    Vågerö D, Ahlbom A, Olin R, Sahlsten S. Cancer morbidity among workers in the telecommunications industry. Br J Ind Med 1985;42:191-5.

    Van Den Eeden SK, Friedman GD. Exposure to engine exhaust and risk of subsequent cancer. J Occup Med 1993;35:307-11.

    van't Veer P, Lobbezoo IE, Martín-Moreno JM, Guallar E, Gómez-Aracena J, Kardinaal AFM, Kohlmeier L, Martin BC, Strain JJ, Thamm M, van Zoonen P, Baumann BA, Huttunen JK, Kok FJ. DDT (dicophane) and postmenopausal breast cancer in Europe: case-control study. Br Med J 1997;315:81-5.

    Vaughan TL, Lee JAH, Strader C H. Breast cancer incidence at a nuclear facility: Demonstration of a morbidity surveillance system. Health Phys 1993;64:349-54.

    Vena JE, Cookfair DL, Fiedler RC, Barnes RE. Mortality of a municipal worker cohort: II. Females. Am J Ind Med 1986;9:159-69.

    Vena JE, Graham S, Zielezny M, Brasure J, Swanson MK. Occupation exercise and risk of cancer. Am J Clin Nutr 1987;45:318-27.

    Vena JE, Petralia SA. Women in the public sector: cancer mortality. J Occup Environ Med 1995;37:277-81.

    Versluys JJ. Cancer and occupation in the Netherlands. Br J Cancer 1949; 3:161-185

    Vihko VJ, Apter DL, Pukkala EI, Oinonen MT, Hakulinen TR, Vihko RK. Risk of breast cancer among female teachers of physical education and languages. Acta Oncol 1992;31:201-4.

    Walker JT, Bloom TF, Stern FB, Okun AH, Fingerhut MA, Halperin WE. Mortality of workers employed in shoe manufacturing. Scand J Work Environ Health 1993; 19:89-95.

    Walrath J, Decouflé P, Thomas TL. Mortality among workers in a shoe manufacturing company. Am J Ind Med 1987;12:615-23.

    Walrath J, Li FP, Hoar SK, Mead MW, Fraumeni JF. Causes of death among female chemists. Am J Public Health 1985;75:883-5.

    Wang JX, Boice JD, Li BX, Zhang JY, Fraumeni JF. Cancer among medical diagnostic X-Ray workers in China. J Natl Cancer Inst 1988;80:344-50.

    Ward EM, Ruder AM, Suruda A, Smith AB, Halperin W, Fessler CA, Hoar Zahm S. Cancer mortality patterns among female and male workers employed in a cable manufacturing plant during World War II. J Occup Med 1994;36:860-6.

    Watkins DK, Chiazze L Jr,Fryar C. Historical cohort mortality study of a continuous filament fiberglass manufacturing plant. II. Women and minorities. J Occup Environ Med 1997;39:548-55.

    Weiland SK, Mundt KA, Keil U, Kraemer B, Birk T, Person M, Bucher AM, Straif K, Schumann J, Chambless L. Cancer mortality among workers in the German rubber industry. Occup Environ Med 1996;53:289-98.

    Wignall BK, Fox AJ. Mortality of female gas mask assemblers. Br J Ind Med 1982;39:34-8.

    Wiklund K, Dich J. Cancer risks among female farmers in Sweden. Cancer Causes Control 1994;5:449-57.

    Wiklund K, Holm L-E, Eklund G. Cancer risks in Swedish Lapps who breed reindeer. Am J Epidemiol 1990;132:1078-82.

    Williams RR, Stegens NL, Goldsmith JR. Associations of cancer site and type with occupation and industry from the Third National Cancer Survey interview. J Natl Cancer Inst 1977; 59:1147-85.

    Wolff MS, Toniolo PG, Lee EW, Rivera M, Dubin N. Blood levels of organochlorine residues and risk of breast cancer. J Natl Cancer Inst 1993;85:648-52.

    Wong O, Trent LS, Whorton MD. An updated cohort mortality study of workers exposed to styrene in the reinforced plastics and composites industry. Occup Environ Med 1994;51:386-96.

    Wong O. A cohort mortality study and a case-control study of workers potentially exposed to styrene in the reinforced plastics and composites industry. Br J Ind Med 1990;47:753-62.

    Yin SN, Hayes RB, Linet MS, Li GL, Dosemeci M, Travis LB, Li CY, Zhang ZN, Li DG, Chow WH, Wacholder S, Wang YZ, Jiang ZL, Dai TR, Zhang WY, Chao XJ, Ye PZ, Kou QR, Zhang XC, Lin XF, Meng JF, Ding CY, Zho JS, Blot WJ. A cohort study of cancer among benzene-exposed workers in China: overall results. Am J Ind Med 1996;29:227-35.

    Zhang Z-F, Yu S-Z, Li W-X, Choi BCK. Smoking, occupational exposure to rubber, and lung cancer. Br J Ind Med 1989;46:12-5.

    Zheng W, Shu XO, McLaughlin JK, Chow W H, Gao YT, Blot WJ. Occupational physical activity and the incidence of cancer of the breast, corpus uteri, and ovary in Shanghai. Cancer 1993;71:3620-4.