Women who work more than 45 hours per week may have an increased risk of developing diabetes, the results of a new study suggest.
According to the findings, an increased risk was not found among those working between 30 and 40 hours per week.
An estimated 439 million adults worldwide will be living with diabetes by 2030. In 2015 alone, the condition cost the global economy €1.13 trillion.
Previous research has found a link between long working hours and the risk of diabetes, however most of this has focused solely on men. Canadian researchers decided to carry out a study involving women as well, in order to paint a more comprehensive picture of diabetes risk.
They monitored the health of over 7,000 workers aged between 35 and 74 over a 12-year period. Working hours were divided into four groups - 15-34 hours, 35-40 hours, 41-44 hours and 45+ hours.
A range of influencing factors were taken into account, such as age, marital status, long-term health conditions, lifestyle and body mass index (BMI).
Workplace factors were also taken into account, such as shift work and whether the job was active or sedentary.
During the study period, 10% of participants developed type 2 diabetes, with diagnoses more common among men, older people and obese people.
The researchers found that the length of the working week was not linked with an increased risk of diabetes among men. In fact, the incidence of the condition appeared to fall the more a man worked. However, the same could not be said about women.
Women who worked more than 45 hours per week had a 63% increased risk of developing diabetes compared to those who worked between 35 and 40 hours.
This effect was only slightly reduced when factors such as BMI and activity levels were taken into account.
The researchers acknowledged that this is an observational study, so no definitive causal effect can be established. They also found no obvious explanation for the results, however, they pointed out that women overall may work longer hours when household chores and family responsibilities are taken into account.
Long working hours may prompt a chronic stress response in the body, increasing the risk of hormonal problems and insulin resistance, they suggested.
"Considering the rapid and substantial increase of diabetes prevalence worldwide, identifying modifiable risk factors, such as long work hours, is of major importance to improve prevention and orient policy making, as it could prevent numerous cases of diabetes and diabetes-related chronic diseases," the team from the Institute for Work & Health in Ontario concluded.
Details of these findings are published in the journal, BMJ Diabetes Research & Care.
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