A certain amount of stress can be positive, but excessive workplace worries such as having little or no control over what you do on the job is a big factor in whether you develop diabetes, especially if you're a woman, according to a Canadian study released today.

"How men and women react to stress is not totally clear, but it’s clear that in the work environment, stress can have an impact on health," Dr. Richard Glazier, one of the Toronto researchers who conducted the study published Tuesday, said in an interview with CBC News.

With diabetes a growing public health concern, Glazier and his research colleagues with the Institute for Clinical Evaluative Sciences, St. Michael's Hospital in Toronto and the University of Toronto examined the relationships between the "psychosocial" work environment and the incidence of diabetes among people between ages 35 and 60 who weren't self-employed. They note that there has been a large amount of work examining the relationship between the psychosocial work environment and high blood pressure and heart disease, but few studies examining work stress and the risk of diabetes.

The Toronto-led study, in the Journal of the Society of Occupational Medicine, was based on data on 7,443 people taken from the 2000-01 Canadian Community Health Survey and linked to statistics of the number of doctor visits and hospital admissions. Those individuals never had diabetes, were not self-employed and had worked more than 10 hours a week for more than 20 weeks over a year.

Glazier said the study finding — that low levels of job control were associated with an increased risk of diabetes among women, but not among men — is consistent with the only other population-based study of this type, undertaken in Sweden.

Although it wasn't determined why women are more at risk of diabetes because of workplace stress — a subject for followup research — there are some theories.

In the interview, Glazier said women and men tend to react differently to stress — physiologically and behaviourally — and the type of jobs they do may also play a role. Women have a different hormonal makeup than men, may tend to turn to unhealthy habits like eating so-called comfort foods containing fat and sugar, and generally have less physical jobs.

"The mind and body are very connected, and the body releases stress hormones like epinephrine and cortisol," he says. "These can help ward off threats, but when released constantly, they take a toll on the body and they really affect how the body handles sugars and fat, and can lead toward the development of obesity and Type 2 diabetes."

Micromanaging can be dangerous?

The Toronto-led study took four health-behaviour measures into account:

• Whether workers were inactive, moderately active or active in the previous three months.
• Whether they smoked and if they did, how many cigarettes.
• Whether they were drinkers.
• Their consumption levels of fruits and vegetables.

The researchers then examined the relationship between those variables and the probability of diabetes over the nine-year followup period, including adjusting for each worker's body mass index (BMI) and health behaviours.Toronto scientist Dr. Richard Glazier and colleagues say their study is one of the few examining the relationship between psychosocial work conditions and diabetes. (St. Michael's Hospital)

One odd finding was that contrary to the researchers' hypothesis that getting high levels of support in the workplace would help reduce the risk of diabetes, Glazier said the research found women getting such help were still at increased risk of diabetes — while men weren't.

“The literature suggests the combination of a lot of work stress and poor social support is really bad for you ... we were very surprised when we found low social support at work was good for you." said Glazier.

"We don’t know why being unsupported by your supervisor is good for you. We only measured these things at baseline – starting in 2001 and followed for nine years. Maybe those people left those [more stressful] jobs and got better jobs – which would be another part of research that would need to be done.”

While there are a lot of questions still to be answered, the researchers urged employers to re-examine the amount of control they give employees over their jobs — in other words, rethink the idea that micromanaging is effective and good for workers. Glazier said studies have shown that workers who have more autonomy and control over their jobs have more job satisfaction, "and less stress and more productivity."