Work, diabetes and obesity: a seven year follow-up study among Danish health care workers

The rise in prevalence of diabetes is alarming and research ascribes most of the increase to lifestyle. However, little knowledge exists about the influence of occupational factors on the risk for developing diabetes. This study estimates the importance of work and lifestyle as risk factors for developing diabetes mellitus among healthcare workers and explores the association of work factors and obesity, which is a risk factor for diabetes.

Questionnaire-based prospective cohort study among 7,305 health care workers followed for seven years in the Danish National Diabetes Register. We used bivariate comparisons to give an unadjusted estimate of associations, followed by adjusted survival analysis and logistic regression models to estimate the influences of potential risk factors related to job, health and lifestyle on diabetes and obesity.

During seven years of follow up, 3.5% of participants developed diabetes, associated with obesity (HR  =  6.53; 95% CI 4.68-9.10), overweight (HR  =  2.89; CI 2.11-3.96) age 50-69 y (HR  =  2.27; 95% CI 1.57-3.43) and high quality of leadership (HR  =  1.60; CI 1.19-2.16). Obesity at baseline was most common among the youngest employees, and was mainly associated with developing diabetes (OR  =  3.84; CI 2.85-5.17), impaired physical capacity and physical inactivity. In the occupational setting, obesity was associated with shift work, severe musculoskeletal pain, low influence, but also by good management, fewer role conflicts and a positive work-life balance. Looking only at non-smokers, removed the influence of age and pain. However, non-smokers also had higher depression scores and more role conflicts.

Confirming obesity as the strongest risk factor for developing diabetes, the present study identified few occupational risk factors. However, obesity, the key risk factor for diabetes, had a more variable relation with work than did diabetes.