(HealthDay News) — Increased sleep duration is associated with increased risk of incident type 2 diabetes, according to a study published online June 11 in Diabetes Care.

Jane E. Ferrie, PhD, from the University of Bristol in the United Kingdom, and colleagues examined whether a change in sleep duration is associated with incident diabetes using data waves spanning more than 20 years. Sleep duration was reported at the beginning and end of four five-year cycles from 1985–1988 to 2007–2009.

The researchers found that after adjustment for age, sex, employment grade, and ethnic group, an increase of at least two hours of sleep per night correlated with an increased risk of incident diabetes compared with a reference group of persistent seven-hour sleepers (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.15–2.37). After adjustment for body mass index (BMI) and change in weight, the correlation was partially attenuated (OR, 1.50; 95% CI, 1.04–2.16). Persistent short sleepers (average ≤5.5 hours/night) had an increased risk of incident diabetes (OR, 1.35; 95% CI, 1.04–1.76), but the correlation was no longer significant after adjustment for BMI and change in weight (OR, 1.25; 95% CI, 0.96–1.63).

“This study suggests that individuals whose sleep duration increases are at an increased risk of type 2 diabetes,” the authors write. “Greater weight and weight gain in this group partly explain the association.”

Full Text (subscription or payment may be required)