Sex/gender analysis: Gender study finds overwork linked to higher risks of diabetes in women, not men

Research by Institute for Work & Health and Institute for Clinical Evaluative Sciences followed 7,300 Ontario workers for 12 years to examine link between work hours and health outcomes

Published: August 3, 2018

Why is it important for work and health researchers to take into account differences between men and women? Because social and biological differences between men and women may influence how work exposures affect health outcomes. A compelling example of this can be found in a new study by the Institute for Work & Health (IWH) and the Institute for Clinical Evaluative Sciences (ICES) on the link between overwork and diabetes.

The study, published in July 2018 as an open access article in BMJ Open Diabetes Research & Care (doi:10.1136/bmjdrc-2017-000496), found women who worked more than 45 hours a week faced a 63 per cent greater risk of developing diabetes than women who worked 35-45 hours a week. In contrast, the incidence of diabetes tended to go down among men who worked longer hours, though the effects were not statistically significant.

The study highlights the importance of conducting sex/gender analyses in research on work and health, says Dr. Mahée Gilbert-Ouimet, a post-doctoral fellow at IWH and lead author of the study.

Previous studies on the link between working long hours and diabetes have found mixed results, and one reason for that might have been the fact that most of these studies looked at male-only or female-only samples, she adds. 

The study followed 7,300 Ontario workers aged 35-74 who were initially free of diabetes. These workers were respondents to the 2003 Canadian Community Health Survey (CCHS), administered by Statistics Canada. The survey collected information on a broad array of personal factors, health conditions, health behaviours and work conditions, including average hours worked a week. The researchers then linked the CCHS information to administrative health records housed at ICES to identify people who were diagnosed with diabetes over the next 12 years (2003-2015).

Their analysis took into account a broad range of potentially confounding factors, including marital status, family status, other chronic health conditions, activity restrictions at work, physical demands at work, primary posture at work, and health behaviours such as smoking, drinking and exercise.

Although the study could not identify reasons for the link between long work hours and risks of diabetes in women, Gilbert-Ouimet suggests that women’s responsibilities outside work—in doing house chores, child-rearing or other forms of care-giving—may be a factor. Differences in the types of work that men and women do may be another factor to consider, she adds.

Research elsewhere has shown a link between overwork and diabetes among people of lower socioeconomic status, so we might be looking at a similar effect among women, she says. It could also be that men who work long hours are more likely to be highly skilled, whereas women who work long hours are more likely to work in low-status occupations. As well, it could also be the case that men who work long hours are more likely to have partners who work fewer hours, so the stress levels they experience at home may be different.