Job control greater risk factor than smoking, drinking, study says
Women with low job control are at greater risk of diabetes, according to a new nine-year study by researchers at the Institute for Work & Health (IWH) and the Institute for Clinical Evaluative Sciences (ICES).
The study defines job control as the ability of individuals to make decisions about the way they work or use their skills. Given the increasing prevalence of diabetes in Canada, low job control might be an important modifiable risk factor to reduce the occurrence of diabetes among the female population, the study finds.
“Increasing levels of job control for women at work, such as providing autonomy over the way they do their jobs, along with improving health behaviours, should be considered as part of a comprehensive diabetes prevention strategy,” says Peter Smith, an IWH scientist and lead author of the study.
There are two primary pathways linking high psychosocial work stress to diabetes risk, the study finds:
- disruptions to neuroendocrine and immune system functioning, and increased or prolonged cortisol and sympathetic hormone release, in reaction to stress
- changes in health behaviour patterns, particularly those related to diet and energy expenditure, possibly as coping mechanisms.
While research has examined the relationship between the psychosocial work environment and hypertension and heart disease, relatively few studies have examined the relationship between psychosocial work conditions and diabetes. In Ontario, the prevalence of diabetes in 2005 had already surpassed the predicted global rate for the year 2030, almost doubling between 1995 and 2005, according to the study.
“Given the increasing prevalence of diabetes in Canada, it is important to identify modifiable factors that might increase or decrease the risk of this disease in women," says Richard Glazier, one of the study's co-authors and a senior scientist at ICES. "While our study shows that high body mass index is probably the most important risk factor, low job control among women also plays an important role in diabetes risk.”
The researchers found low levels of job control were associated with an increased risk of diabetes among women, but not among men. The proportion of cases of diabetes among women that could be attributed to low job control was 19 per cent. This was higher than that for other health behaviours, such as smoking, drinking, lack of physical activity and unhealthy eating — but lower than that for obesity, to which 42 per cent of cases could be attributed.
The study, funded by the Canadian Institutes of Health Research, followed 7,443 actively employed (but not self-employed) people aged 35 to 60 in Ontario who had no previous diagnosis of diabetes. The study group was followed for nine years. The researchers used data from the 2000-2001 Canadian Community Health Survey linked to the Ontario Health Insurance Plan (OHIP) database for physician services and the Canadian Institute for Health Information Discharge Abstract Database for hospital admissions.
IWH is a not-for-profit organization that conducts and shares research to protect and improve the health of working people. ICES is an independent, not-for-profit organization that uses population-based health information to produce knowledge on a broad range of health-care issues.
