“Type 2 diabetes is more common in people who work shifts, a large international study suggests,” BBC News reports.
The BBC reports on a review that searched the literature and found 12 studies including more than 225,000 people which looked at the link between shift work and diabetes.
When pooling the results the researchers found that overall, shift work was associated with a 9% increased risk of diabetes. The association was found to be stronger in men (37%) and for those working rotating shifts – such as two weeks on nights, two weeks on days (42%).
However, there are problems with concluding from these studies that there really is a link between shift work and developing diabetes. For example, it is difficult to establish cause and effect, because it’s not completely clear that people hadn’t already got diabetes at the time their shift work pattern was being assessed. It’s further unclear whether the apparent relationship may not just be caused because of other factors that are associated with both shift work and diabetes (such as diet and activity).
Also, none of the 12 studies were conducted in the UK, and half were from Japan. While the results may be applicable here, different cultures may have different a work ethic, environmental and health differences, meaning that they cannot so easily be generalised to all populations.
The identified relationship is undoubtedly worthy of further study, to see whether shift work could have direct biological effects on the body that lead to the development of diabetes.