Progress seen in occupational disease prevention, but data still lacking: speaker

At IWH’s 2018 Nachemson lecture, occupational cancer expert Dr. Paul Demers highlights need for improved exposure surveillance, and more evaluation studies

Published: February 14, 2019

With the continued rise in the number of deaths due to occupational disease and work-related cancers, disease prevention is moving to the top of the agenda in many jurisdictions, including Ontario.

However, to push forward on this prevention agenda, policy-makers and prevention systems need more data, especially in hazard and exposure surveillance, said Dr. Paul Demers, who took to the podium at the 2018 Alf Nachemson Memorial Lecture, hosted by the Institute for Work & Health (IWH).

Also needed is more research to identify the most effective ways to reduce exposures, said Demers at the November 28 public event, now available as a slidecast. Demers, director of the Occupational Cancer Research Centre, based at Cancer Care Ontario, is internationally recognized for his expertise on the health effects of workplace exposures. Subsequent to the lecture, he was appointed by Ontario’s Ministry of Labour to lead a review of the recognition and compensation of occupational cancer, an appointment welcomed by IWH President Dr. Cam Mustard.

In Canada, it has been 15 years since compensated deaths from occupational disease overtook the number caused by work-related traumatic injuries and disorders. The International Labour Organization estimates that, worldwide, for every person who dies from a traumatic work-related injury, about six people die from occupational diseases. That ratio is even higher in countries such as Canada, where traumatic injury rates have gone down.

In Ontario, the issue is considered an occupational health and safety priority, as seen in the creation of the Occupational Disease Action Plan (ODAP) in June 2016. The implementation team, with representatives from across the province’s prevention system, as well as Public Health Ontario and the Lung Association, identified noise, allergens/irritants and diesel exhaust as the initial priorities, followed by asbestos and silica.

Such initiatives may signal progress, but Demers noted that recognition of occupational disease continues to be a challenge  for several reasons. Diagnosis can occur long after exposure, so a full work history is needed. Dose is a strong predictor of the likelihood of diseases, but people may not know the extent of their past exposures. Most of these diseases have multiple causes, making work attribution a matter of debate. And, finally, individuals vary in how susceptible they may be.

To illustrate ongoing challenges around the recognition of work-related diseases, Demers pointed to his team’s research on the burden of work-related exposure to asbestos. Estimates drawn from modelling put the national number of newly diagnosed cases of lung cancer in 2011 attributable to work-related asbestos exposure at 1,900 and the number of newly diagnosed cases of mesothelioma at 500. And yet, across Canada, less than 10 per cent of lung cancers caused by work-related asbestos exposure are compensated. Even for mesothelioma, the proportion of cases that are compensated stands at about 60 per cent nationally.

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Some progress seen

Demers also spoke of some progress being made on disease surveillance. One example is the Occupational Disease Surveillance System, set up in 2017 to follow 2.2 million lost-time claimants in Ontario since 1983 to track their risk of disease. This dataset, importantly, has information about occupation and industry, which allows researchers to measure the risks of specific work-related diseases for specific occupational groups. This system has already helped reveal notable findings, such as the elevated risks of asbestos-related diseases among custodians and skilled trades workers in the education system. That’s due to the presence of asbestos in schools built before the mid-1970s, he noted.

While acknowledging the progress made on disease surveillance, to get ahead of the game, we’ve got to start figuring out some way to do exposure surveillance, Demers emphasized. Such a surveillance system would allow policy-makers to monitor trends in exposure, identify at-risk populations or geographic areas, and set priorities for prevention efforts.

He pointed to a few promising examples of exposure registries, including Health Canada’s National Dose Registry or the Ontario Asbestos Worker Registry, set up by Ontario’s Ministry of Labour. For an example of a program with great potential on exposure reduction, Demers singled out Ontario’s Toxics Reduction Program, which requires manufacturing and processing facilities to report their use of toxic substances and encourages these facilities to set out a yearly plan to reduce these substances. With a few tweaks to this, we could actually be collecting more useful data for workplaces, making it not just environmentally focused, but also workplace focused, he said. (Demers made these remarks before the province announced plans to scale back the program, including the reporting requirement for certain facilities.)

Turning his attention to exposure prevention programs, Demers highlighted a few examples, ranging from legislation to workplace controls. “A challenge with many of these initiatives is we don’t do enough evaluation to know how effective they are,” said Demers, emphasizing the need for more prevention research with a strong evaluation component.

There’s a misconception that exposure to hazards at work affects only a limited number of blue-collar occupations, but it hits a wide variety of occupations and a wide variety of workers, said Demers in closing. It’s a major societal problem.