Long Hours in Low Socioeconomic Jobs Linked to Type 2 Diabetes

The Lancet Diabetes and Endocrinology journal has published the results of the largest study into the field of diabetes and long working hours so far, and found that people working more than 55 hours per week in a manual or low socioeconomic job have a 30% greater risk of developing type 2 diabetes.

University College London's professor of epidemiology Mika Kivimäki and colleagues conducted a review and meta-analysis of published studies and unpublished individual-level data examining the effects of long working hours on type 2 diabetes, concluded in late April this year.

The analysis involved 222,120 men and women from the USA, Europe, Japan and Australia who were monitored for an average of 7.6 years, and the results found that those working more than 55 hours per week had a greater risk of developing type 2 diabetes than those working a regular 40 or under.

A further analysis of the results, however, revealed that the individuals working these longer hours in low socioeconomic jobs had about a 30% increased risk of developing the disease than their lowsocioeconomic working counterparts who worked 35-40 hours a week. Surprisingly, health behaviours like smoking and physical activity and other risk factors like age, sex and obesity were taken into account, and did not affect change the outcome.

The researchers said that further research is needed to discover the underlying causes, but suggested that working disruptive schedules that affect sleeping, unwinding and exercise could be a major component.

According to Professor Kivimäki, “The pooling of all available studies on this topic allowed us to investigate the association between working hours and diabetes risk with greater precision than has been previously possible. Although working long hours is unlikely to increase diabetes risk in everyone, health professionals should be aware that it is associated with a significantly increased risk in people doing low socioeconomic status jobs".