Night-shift work is linked to an increased risk for Type 2 diabetes, a new study has found. British and U.S. researchers used a large health database to compare diabetes prevalence in 47,286 night-shift workers with that of 224,928 day workers.

The database included information on age, sex, race, family history of diabetes, alcohol use, sleep duration, body mass index and other health and behavioral characteristics, as well as diagnoses of diabetes.

After controlling for other factors associated with diabetes, they found that the more often people worked nights, the more likely they were to have diabetes. Compared with day workers, people who occasionally worked night shifts were 15 percent more likely to have diabetes; those who rotated shifts with some night work were 18 percent more likely; and those who worked irregular shifts with frequent night shifts were 44 percent more likely to have Type 2 diabetes. The study is in Diabetes Care.

The lead author, Céline Vetter, an assistant professor at the University of Colorado, said night work can misalign circadian rhythms, reduce energy expenditure and cause partial sleep restriction, all adding to the risk.