Occupational Disease Panel (Industrial Disease Standards Panel) Annual Report 1997/98

(source: Medical Research Council of Canada)

I. OCCUPATIONAL DISEASE, RESEARCH AND PREVENTION

During the last ten years the Occupational Disease Panel has worked independently of the Workers' Compensation Board, the body responsible for the administration of benefits, to conduct research into possible sources of occupational disease. While independent of the Board the Panel has given careful consideration of the needs of the Board and the concerns of the workplace.

The role of research is critical. If there is no research there can be no prevention because the sources of disease will never be identified.

In recent years, research into occupational health has resulted in the modification of many work practices aimed in part to improve the health of workers. For example, in the automotive sector oil mist exposures were reduced far below government standards by contractual agreement. INCO changed from oil lubricants to grease in October 1997, thereby eliminating exposure to oil mists. In both mining and automotive sectors, companies are experimenting with fuels and lubricants made from vegetable oils.

The role of the government to continue to fund research is critical. It is only the government which has the ability to see beyond competitive concerns of private industry and collect data from a sufficiently broad base to allow the results to be truly meaningful. However, as shown in the chart below the role of government in Canada has been diminishing. If prevention is the real goal, this pattern cannot be allowed to continue.

In this our last report the ODP has identified two areas which require immediate consideration. The first area is the need for an organized data collection system, and the second comprises specific projects that should be pursued and adequately funded. The Panel hopes that these final thoughts may begin the process that will result in a long term occupational disease prevention programme for the Ontario government.

II. DATA COLLECTION

Concerns about the absence of a national or at a minimum a, provincial data collection system to facilitate the investigation of occupational diseases has been a recurring theme for decades. Scientists, labour and management representatives and Royal Commissioners have all identified the absence of a data collection system as a continuing impediment to occupational disease research.

Unfortunately, no province in Canada has a structured method of collecting data about working populations. Since this data is not systemically collected, each and every time researchers want to investigate the health effects peculiar to a work environment, the cost of the project usually becomes restrictive because of the cost of data collection.

Over the years the ODP has recommended several methods which could have allowed for the development of components to a data collection system. Most of these initiatives would not be expensive.

A) Social Insurance Numbers and Principle Occupations on Death Certificates

In 1993 the Panel wrote to the Ontario Deputy Minister of Consumer and Commercial Relations and requested that social insurance numbers and principal occupation in a machine readable form be included on all death certificates. The Panel was convinced that registering this type of data would greatly advance the study of occupational disease in Ontario. If this recommendation were to be followed there could be a running examination of the most prevalent occupational diseases. This recommendation remains outstanding.

B) Maintenance of the Occupational Cohorts like the Mining Master file

Much of the internationally recognized occupational epidemiology conducted in Ontario was possible because of the Mining Master File (MMF). The MMF contains over 90,000 entries recording the work and health experience of underground miners in northern Ontario. For reasons that were never clear the Ministry of Labour decided not to update the MMF in the late 1980's and the data base has now fallen into disuse. This was the only occupational cohort captured in Ontario that accumulated data from more than one employer.

The value of such a data base can not be overstated and the Ontario Mining Association in its many responses to the ODP reports has relied on the data base to evaluate the conclusions reached about occupational diseases. For example, in response to the ODP Report #12A, the Addendum to the Hardrock Mining Report, the OMA recommended:

That the combined INCO and Falconbridge cohort dataset resident at McMaster University be linked with the Mining Master File in order to determine the influence of possible confounding based upon other risky mining experience [viz. early gold mining and later uranium exposures]

While it may no longer be possible to update the original MMF it may still be possible to create a new data base with the outstanding records.

C) Joint Ventures with Corporations and Unions

The former Premier's Council on Health, Well-being and Social Justice recommended:

To prevent work-related injury and illness, Ontario must know where the serious problems are. Efforts should be directed towards improving the collection and monitoring of information that can be used to determine patterns of occupational injury and illness and identify priority hazards in the workplace.

With these goals in mind the Panel looked at data collection processes that were working outside the government sphere. These activities included the work of the INCO/ SteelWorkers Joint Occupational Health Committee and Dofasco. The INCO Joint Committee was the result of a contractual agreement to fund ongoing epidemiological studies of the INCO worker cohort of 54,000.

The ODP approached the Chrysler Corporation to determine if it would agree to a pilot study, funded by the Panel, to consider the feasibility of establishing an occupational data base for the purpose of measuring health effects on exposures to workers, Specifically the Panel wanted to see if the corporations payroll data base could be modified electronically. The modified occupational data base that could then be matched with other data bases including the national mortality data base, to assess the health of Chrysler workers.

At that time the Corporation declined; however, since then there have been negotiated agreements to target funds for joint occupational health research. This may well be the kind of project that both labour and management can agree to with technical assistance from either the WCB or the Ministry of Labour.

D) CROME (Computerized Recording of Occupation Made Easy)

In conjunction with the Southwestern Regional Office of Cancer Care Ontario (previously the Ontario Cancer Research and Treatment Foundation) and the Occupational Health Clinic for Ontario Workers (Windsor) the ODP created a computer programme to allow workers to electronically record their occupational histories. The programme was designed to create a complete work history that would be electronically retrievable and easily matched with other electronic data bases. The occupations are recorded in accordance with the standardized occupational codes for wider access.

This system is currently in use at the Regional Cancer Centre in Windsor, the first cancer centre in the province to include occupation as a standard entry in the patient's history. In the best of all worlds the other regional cancer centres will also adopt this approach and begin to include occupation in their history taking. This would be the first step to an improved ability to identify work-related sources of cancer.

III. SPECIFIC RESEARCH INITIATIVES

Over the past several years there has been growing body of evidence and public concern about specific issues like exposure to electro-magnetic fields and aluminum . The Panel has identified a number of these issues which require additional research and placed them on its long term agenda. Because of the Government's initiatives to disband the ODP there has not been an opportunity to develop these projects or secure the funding necessary to undertake the investigations. In this its last Report the Panel believes that it is necessary to identify unfinished projects, for future consideration.

A) The Welding Process and its Possible Health Effects

Dr. G. Liss of the Ontario Ministry of Labour completed a review of the literature on the health effects of welding.

In his review, Dr. Liss repeatedly found elevated rates of pneumonia among welders. This finding appears to warrant evaluation and consideration for possible WCB guidelines and prevention activity.

Dr. Liss also noted that Dr. Steenland's most recent work on welding and lung cancer was methodologically sound. Dr. Steenland's findings, which did not identify elevated rates of lung cancer were inconsistent with the results of several other studies. Upon review, it became apparent that the follow up of Dr. Steenland's study was short and may have resulted in an underestimation of the true risk of lung cancer among welders. Six years have past since the study was completed and Dr. Steenland advised the Panel that the number of cases available for evaluation has now doubled since he published his study. The Panel is of the view that a further analysis of the more complete data is warranted. This additional research may provide more definitive evidence on the relationship between lung cancer and welding.

B) The Health Effects of Antineoplastic Drugs on Health Care Providers

Drugs prescribed for the treatment of cancer (antineoplastic drugs) may have significant side effects including other cancers and liver damage among patients. There is a growing suspicion based on case reports that health care providers who administer and prepare the antineoplastic drugs may also experience some adverse health effects.

Unfortunately there is not sufficient data about the health of these workers to draw firm conclusions about the effects of antineoplastic drugs on them. There is, however, a body of evidence which points to a relationship which should be included in a WCB review of any claims from these health care workers for illness that might be secondary to the administration of anti-neoplastic drugs.

The WCB should also give careful thought to the development of a protocol, which would comply with standard scientific methods, to evaluate the concerns of these workers.

C) Investigation of the Health Effects resulting from Occupational Exposure to Electro Magnetic Fields

Both the Canadian Auto Workers and the Communication, Energy and Pulp and Paper Workers asked the ODP to investigate the health effects of workers exposed to electro magnetic fields. The concerns of these unions about there membership heightened when the team conducting research on electric utility workers from Ontario, Quebec and France found elevated rates of leukaemia. The researchers did not find a dose/response. ( Therriault et al, American Journal of Epidemiology, 1994)

Of additional concern were the clusters of breast cancer found among premenopausal women working for a large phone company. These clusters became public; however the scientific reports on the clusters were not publicly reported.

Unfortunately the ODP had neither the resources or the time to properly investigate these issues. However, the growing level of public concern around these issues warrant serious consideration by the new research advisory committee at the WCB. Research on this subject and evaluation of the currently available data is necessary.

D) Hearing Loss and chemical exposure

Hearing loss and exposures to chemicals has been a growing issue of concern. There is a significant literature on the relationship between solvent exposure and hearing loss. The evidence is also mounting on the connection between chronic carbon monoxide exposure and hearing loss.

This literature has never been carefully examined by the Panel or the Board but clearly warrants consideration.

E) Benzene Exposure and Haemopoitic Cancers other than Leukaemia

There is a well established link between benzene and leukaemia. There is also a growing body of literature which supports the relationship between benzene exposure and lymphatic cancers. The most recent data comes from a large Chinese study conducted by Hayes et al., published in the Journal of the National Cancer Institute, July 1997. This study together with other research strongly suggests that there may be an association between benzene exposure and all haematological neoplasms. The WCB in its new research role should review the literature and consider the relationship between benzene and cancers other than leukaemia.

F) Breast Cancer and Occupation

While the mortality rates for breast cancer are dropping, more and more women are being diagnosed with the disease. There has been an approximate 30% increase in the incidence of breast cancer over the last 30 years.

It is of interest that increased rates of breast cancer mirror the increased rate of women entering the labour force.

As one of its last projects the Panel contracted with Dr. France Labreche to review the literature which examines the relationship between occupation and breast cancer. Her report identifies areas of interest and concern and the Panel would strongly recommend that consideration be given to further evaluation of that data.

G) Chronic Obstructive Lung Disease

The association between work exposures, specifically dust and chronic obstructive lung disease has been an issue of interest to the Panel for a number of years. This is a difficult subject to research because the incidence rates of chronic diseases are difficult to calculate.

In 1993 Dr. David Muir at McMaster along with several colleagues examined the relationship between dust exposure and the rates of chronic obstructive lung disease. They were rigorous in their selection of studies and ultimately included 4 studies in their review. In each of those studies there were statistically elevated rates of loss of lung function, when workers were exposed to respirable dust exposure.

Because of their rigid criteria, the only studies included in the review concerned British coal mines. While this analysis showed elevated rate of COLD among coal miners, there was some reluctance on the Panel to assume that the experience of other workers was identical.

The Panel is firmly of the opinion that there is a need to study and evaluate the relationship between occupational exposure to dust and elevated rates of COLD among Ontario workers.

H) Cluster Registries

Since 1985 the ODP has examined the need and usefulness of a cluster registry. The regisrty would accumulate data on disease clusters identified in individual workplaces.

The Panel is of the view that a registry of occupational disease clusters will be of benefit in identifying potential problems. A registry will allow people to identify more than one similar cluster and identify as coincidence any lone cluster.

IV. INVESTIGATIONS

1. Completed Projects 96/97

Laryngeal Cancer in Workers in Primary Nickel Production

The ODP funded a large study of cancer incidence among 65,000 Ontario nickel workers at INCO and Falconbridge which was completed in January 1996. This complex and exhaustive study gives the most comprehensive picture to date of cancers among workers in primary nickel production.

Following analysis of the results pertaining to cancer of the larynx in this and other studies, the Panel was able to issue its Report No. 19, "Report to the Workers' Compensation Board on Cancer of the Larynx in Workers in Primary Nickel Production" in July, 1997. The Panel found "a strong probable connection" between laryngeal cancer and nickel mining and milling and recommended that this disease and the processes be added to Schedule 3 of "The Act".

The Panel also recommended that cases of laryngeal cancer among refinery workers continue to be adjudicated according to existing Board policy and that cases among workers in smelting and sintering operations be adjudicated on a case by case basis.

Elevated rates of laryngeal cancer among Iron Ore Recovery Plant workers prompted the Panel to recommend continued monitoring of these workers by the INCO/USWA Joint Occupational Health Committee and the WCB.

Similarly, the Panel recommended ongoing monitoring for refinery workers at Port Colborne who were originally employed in refining nickel but are now refining cobalt. Recent concerns regarding adverse health effects from cobalt and its compounds have been raised by IARC and the National Toxicology Program in the United States.

Submissions have been received from the workplace parties and now the decision lies with the WCB concerning the implementation of the Report.

Metalworking fluids and cancer of the rectum

In 1993 the Canadian Auto Workers asked the Panel to investigate the possible relationship between occupational exposure to metalworking fluids and a variety of cancers.

The Panel was able to complete the last of its review on this issue in October 1997, following peer reviews of the case control study conducted by Dr E. Eisen and her colleagues at the University of Massachusetts.

The results of the Panel's investigation lead it to conclude that there was a probable connection between exposure to petroleum based MWF's and primary cancer of the rectum. The Panel recommended that the WCB develop guidelines to assist adjudicators in assessing the merits of claims of exposed workers.

2. Projects Funded and Sponsored by the ODP

Northern Ontario Miners Health Survey

Dr.S.L.Rifat and her colleagues at the University of Toronto, conducted a two year follow-up study of gold miners, who until the late 1970's were exposed to aluminum dust in a medical programme aimed at eliminating silicosis. The study was aimed at addressing the concerns arising from the miners' original health survey that seemed to show a relationship between history of exposure to McIntyre powder and poor cognitive screening test results¹.

Specifically, there was concern that the large number of men exposed to aluminum powder between 1944 and 1979 now could be at greater rick of neurodegenerative disorders such as Parkinson's and Alzheimer's diseases.

The study team concluded that the proportions of men with neurocognitive disorders were approximately the same for men with and without a history of exposure to aluminum powder. Within the exposed group, risk of dementia among men with the longest duration of exposure was slightly higher than those exposed for shorter periods, but the risk was not statistically significant. Therefore the study does not confirm the preliminary finding that exposure to the aluminum prophylaxis programme might cause an increase in cognitive impairment. The results of the study were presented at a public meeting in Timmins in August, 1997.

However, Panel members, in a covering letter to those invited to the Timmins meeting, urged caution in the interpretation of the data. The study suffered from a lack of power to detect risk due to the small sample size caused by the poor response rate among those invited to participate in the follow-up. Hence the Panel is of the opinion that the results do not allow for any definitive conclusion regarding the safety of historical exposure to McIntyre powder.

Health Effects of Antineoplastic Drugs

A final version of the Panel-sponsored literature review was released in January, 1997. "Health Effects of Occupational Exposure to Antineoplastic Drugs: An Integrative Research Review" was prepared by Dr. Jeanne Beauchamp Hewitt of the University of Wisconsin and peer reviewed by Drs. B. Valanis and M. McDiarmid. The author concluded that there was adequate limited evidence linking occupational exposure to ANDs and liver fibrosis, congenital malformations, fetal loss, leukaemia and bladder cancer. Preliminary evidence linked other adverse reproductive effects such as low birth weight. This is an occupational health issue related to a predominantly female workplace. Historically, research into women's occupational health has been largely neglected and underfunded.

Health Effects of Welding and Cutting Fume - An Update

Dr. Gary Liss of the Ontario Ministry of Labour was asked to update his 1984 literature review on the health effects of welding. This update was completed in December 1996 and peer-reviewed by Drs. W.S. Beckett, R.Houser, K.Steenland and P. Schulte.

Dr. Liss concluded that there continues to be evidence linking welding fumes and gases with certain acute and chronic health outcomes including pneumonia, metal fume fever, non-malignant respiratory disease and lung cancer.

The issue of increased risk of lung cancer among stainless steel versus mild steel welders and possible confounding by asbestos remains unresolved and the Panel encourages the Workers' Compensation Board to consider funding a follow-up of the excellent study conducted on non-shipyard mild steel welders by Steenland et al. and published in 1991².

Breast Cancer

Dr . France Labrèche of McGill University and the Montreal Public Health Department prepared a literature review on breast cancer and occupation. The review was commissioned in part because of the Panel's concern that the role of potential occupational exposures is rarely considered in discussions of breast cancer causation. Dr. Labrèche will present her findings at a public forum in November. Her manuscript will then be peer-reviewed and a final document published by the end of 1997.

Stomach Cancer among workers exposed to Metal Working Fluids

The Panel funded a study to be conducted by the University of Massachusetts to evaluate the rate and histology of stomach cancer among workers exposed to metal working fluids. The study is designed to determine if the histology of stomach cancer among these workers who have elevated rates of stomach cancer may be masking a dose/response. Specifically the Panel was interested in determining if the pattern of stomach cancer among these workers was the same pattern of disease experienced by the goldminers who also had elevated rates of stomach cancer.

This study was not completed by the time the ODP was closed but the work continued and the results will be reported to the WCB.

V. OUTREACH

September 20, 1996
Telemedicine Series on Occupational and Environmental Medicine.
Carlan presented the topic "Working women's health issues"

On November 15, 1996
Dr. Gary Liss of the Ontario Ministry of Labour presented his paper "Health Effects of Welding and Cutting Fume - An Update" to stakeholders and invited guests.

December 16-18, 1996 Sudbury/Timmins
Seguin and Carlan presented ODP Report No.16, Stomach cancer in Ontario gold miners to stakeholders.

April 17-18, 1997 Toronto
Institute for Work and Health, 1997 Annual Health Conference Creating Healthy Workplaces
Carlan presented the topic " Setting Standards: Lessons for Effecting Change through Workplace-based Research".

May 1, 1997
Workers' Compensation Appeals Tribunal,
Carlan spoke to adjudicators on the Panel's Report on Dupuytren's Contracture

May 14, 1997
Canadian Union of Public Employees (CUPE)
Carlan spoke on "Ontario Women's Work-related Health Survey" and ongoing ODP projects

July 27-30, 1997, Washington, DC
1997 Joint Meeting of the Public Health Conference on Records and Statistics and the Data Users Conference
Tung presented CROME poster

August 14 , 1997 Timmins Ontario
Seguin reported to t he United Steelworkers of America (USWA) and the VOME chapter on the most recent ODP reports.

August 15, 1997, Timmins, Ontario
Northern Ontario Miners' Health Survey
Dr. Sandra Rifat presented to workplace parties the results of her study.

September 9, 1997 , Belleville, Ontario
Service Employees International Union, Locals 183-663
Health and Safety Seminar
Carlan presentation was on the topic of carcinogens in the workplace

September 11, 1997 Thunder Bay, Ontario
Homer Seguin made a presentation on the ODP reports relevant to mining to the health and safety representative of the USWA in Northern Ontario.

VI. ADMINISTRATION 1997/98

All Panel expenses are recoverable from the Workers' Compensation Board.
The Panel's statement of expenditure for the fiscal year 1997/98³ are shown below.

STATEMENT OF EXPENDITURE: As at September 30, 1997 (in 000)

Endnotes

¹  Rifat,S.L.;Eastwood,M.R.; et al. Effects of exposure of miners to aluminum powder. Lancet. Vol.336(1990). p.1162-65.

²  Steenland,K.;Beaumont,J.;Elliot,T. Lung cancer in mild steel welders. American Journal of Epidemiology. Vol.133(1991). p.220-229.

³  The fiscal year runs from April 1, 1997 to March 31, 1998. At the time of printing only the figures for the period April 1 - September 30, 1997 were available.