In women, there is a positive association between rotating night shift work and the risk of developing type 2 diabetes. The findings from a study by Frank Hu and colleagues from Harvard School of Public Health in Boston, published in PLoS Medicine, are of potential public health significance as a large proportion of the working population is involved in some kind of permanent night and rotating night shift work.

The authors used data from the Nurses’ Health Study I (NHS I—established in 1976, and which included 121,704 women) and the Nurses’ Health Study II (NHS II—established in 1989, and which included 116,677 women), and found that in NHS I, 6,165 women developed type 2 diabetes and in NHS II 3,961 women developed type 2 diabetes. Using statistical models, the authors found that the duration of rotating night shift work was strongly associated with an increased risk of type 2 diabetes in both cohorts and that the risks of women developing type 2 diabetes increased with the numbers of years working rotating shifts. However, these associations were slightly weaker after the authors took other factors into consideration.

Although these findings need to be confirmed in men and other ethnic groups, they show that additional preventive strategies in rotating night shift workers should therefore be considered.

"Recognizing that rotating night shift workers are at a higher risk of type 2 diabetes should prompt additional research into preventive strategies in this group," the authors stated.