Workers Health & Safety Centre

Workplace exposures linked with elevated risk of ovarian cancer

Identifying and preventing exposure to a range of chemical agents at work may reduce the risk of women workers developing ovarian cancer, a new Canadian study suggests.

Researchers from the University of Montreal analysed the job histories of nearly 500 women with ovarian cancer. They looked at two dimensions of work including specific job or industry and, using a Canadian job-exposure matrix, each woman’s likely exposure to certain chemicals. This data was then compared with a control group of almost 900 women without ovarian cancer.






Hazardous occupations

According to the findings published in the journal Occupational and Environmental Medicine (OEM) in July 2023, the highest ovarian cancer risk was found for women working 10 years or more as:
  • hairdressers, barbers, beauticians and related workers (322% increased risk)
  • construction workers (279% increased risk)
  • accountants (205%)
  • sewers and embroiderers in the clothing industry (85%)
  • retail work (59%), and
  • sales work (45%).

Hazardous chemical agents

The researchers also identified elevated cancer risk for 18 specific agents with high cumulative exposure. Examples of these agents include cosmetic talc, hair dust, ammonia, hydrogen peroxide, synthetic fibres, polyester fibres, cellulose, formaldehyde, ethanol, isopropanol and polycyclic aromatic hydrocarbons.

What was not clear, according to the researchers, is whether the connection to ovarian cancer is caused by exposure to a single chemical or a combination of agents in addition to other workplace exposures. Take hairdressing for instance. Lead researcher Dr. Anita Koushik, associate professor, Department of Social and Preventive Medicine, University of Montreal School of Public Health, says "Women working in hairdressing-related occupations are exposed to hundreds of chemicals at high concentrations. In our study, employment in hairdressing-related occupations and exposure to 12 agents prevalent in these occupations were suggestively associated with increased risks of ovarian cancer."

The researchers also point out the exposures and occupations mentioned above may not be an exhaustive list explaining they were “unable to assess risk in certain occupations and industries (paper, printing, textile production, dry cleaning, manufacturing) or specific agents (asbestos, pesticides) previously reported as potential ovarian cancer risk factors.”

Learn how to identify, assess and control hazardous exposures at work with WHSC training. Register today for one or more of our training essentials! https://www.whsc.on.ca/Training/Training-Registration

Lack of gender-specific research impedes prevention

Nonetheless explains Dr. Koushik, “The true value of the study is that it provides new information about potential risk factors for ovarian cancer. Very few previous studies investigated occupational hazards for women-dominated jobs, such as hairdressers and beauticians.”

In an editorial also published in the journal OEM, Dr. Melissa Friesen and Dr. Laura Beane Freeman from the US National Cancer Institute echoed this same sentiment explaining this Canadian study "reminds us that while the lack of representation of women in occupational cancer studies — and indeed, even potential strategies to address this issue —have been long recognised, there is still a need for improvement in studying women's occupational risks. By excluding women, we miss the opportunity to identify risk factors for female-specific cancers, to evaluate whether sex-specific differences in risk occur, and to study exposures occurring in occupations held primarily by women."

Legal obligations to protect women workers

The most recent data from the Canadian Cancer Society estimates 3,000 Canadian women were diagnosed with ovarian cancer in 2022. An estimated 1,950 women died. The high fatality rate relates to the fact ovarian cancer is often diagnosed in the later stages making it more difficult to treat. Efforts to protect women from the exposures responsible for this deadly disease are critical. And for employers, they have a legal obligation to do so.

Regulation 833 of Ontario’s Occupational Health and Safety Act, sets out the requirement for employers to consider the hierarchy of controls in meeting their obligations to control biological and chemical agents. This involves beginning with eliminating exposures—in this case substitution with safer chemicals or products should be considered first. Fortunately, there are many resources available to help with this critical task both within the workplace and beyond (see links below).

Joint health and safety committees (JHSCs) and worker health and safety representatives (HSRs) in smaller workplaces can also assist. In fact, they have a legal right to participate in pursuit of safer, healthier work. To ensure JHSCs can effectively act on this right, employers must provide JHSCs in Ontario-regulated and federal-regulated workplaces with training.

The Ontario government is also encouraging employers to train HSRs in smaller workplaces. In fact, they will assist eligible employers recover registration fees and lost-time wages (to a maximum of $50 for registration and $300 for wages) associated with HSR training through a limited time reimbursement program.

Employers must also ensure all workers who may be exposed to a hazardous product participate in general and workplace-specific GHS WHMIS training. This training provides critical insight helping workers, JHSC members, HSRs, supervisors and employers better understand chemicals, how they can cause harm and the best means of eliminating or minimizing exposure.

WHSC can help

As Ontario’s official government-designated occupational health and safety training provider for more than 35 years, Workers Health and Safety Centre (WHSC) helps workplaces comply with these training requirements including GHS WHMISJHSC CertificationHSRs in small workplaces, federal committees and prevention programs and supervisors.

Don’t see what you need? Beyond scheduled classes, and where participant numbers warrant, we can work with you to coordinate almost any of our training courses in-person or online in our virtual classrooms.

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Learn more about this research and related resources

Occupational environment and ovarian cancer risk
Identifying occupational risk factors for cancer in women: a need for further action
Nail technicians exposed to significant levels of harmful toxins, study
Chemical/Agent substitution resources
WHSC WHMIS Resources

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