439 million adults globally are estimated to be living with diabetes by 2030, an increase of 50%, globally diabetes cost the economy $1.31 trillion. Research conducted in the past has suggested links between long work hours and increased risk for diabetes, most of which focused on men. This study focused on women to try and provide a more comprehensive picture of work and diabetes.
7065 Canadian workers aged 35-74 were tracked over a 12 year time frame using national health survey data and medical records. Subjects were grouped into 4 time bands: 45+ hours, 41-44 hours, 35-40 hours, and 15-34 hours, with a range of factors considered including ethnicity, sex, age, place of birth, place of residence, health conditions, BMI, parenthood, and lifestyle. Workplace factors included number of weeks worked, shift work, primarily active or sedentary work, and number of weeks worked.
During the study period 1 in 10 subjects developed type 2 diabetes with more diagnoses among men, older age groups, and among those who were obese.
Length of working week wasn’t associated with increased risk of disease among men, incidence seemed to fall with a longer working week. Female subjects who worked 45+ hours a week had a 63% higher risk. Effect was slightly decreased when factors were taken into account such as BMI, smoking, alcohol, and activity levels.
No definitive causal effect can be established as this was an observational study. Working hours were measured at one point only, which type of diabetes subject had was not able to be determined using records, although type 1 diabetes accounts for 1 in 20 adult cases.
There was no explanation for the gender differences, researchers suggest women working longer hours when household chores and family responsibilities are considered may be partial cause. Longer hours may create chronic stress response and increase risk of hormonal abnormalities and insulin resistance, according to the researchers. Identifying modifiable risk factors for diabetes is of importance to improve prevention and orient policy making to help prevent diabetes and diabetes related chronic diseases.
