Consistently getting too little sleep each night or increasing nightly sleep times over a period of several years were both associated with modest, long-term increases in type 2 diabetes risk in an analysis of women enrolled in the Nurse’s Health Study.
Changes in diet, physical activity, and body mass index did not explain the finding of a small, but significant association with type 2 diabetes risk in middle-aged and older women whose sleep duration increased by more than 2 hours over the 14-year analysis.
Increased Sleep Duration and T2D Risk
Regularly sleeping 6 hours or less a night over the study period was associated with a nonsignificant (hazard ratio of 1.05, 95% CI 0.96-1.16) increase in diabetes risk after adjusting for body mass index (BMI), according to Elizabeth Cespedes and colleagues from the Harvard T.H. Chan School of Public Health in Boston, reporting online in the journal Diabetologia.
Cespedes noted that a new finding from the study is that the adverse influence of sleeping too little does not appear to be ameliorated by increasing sleep duration later in life. Compared to women who reported consistently sleeping 7 to 8 hours, those who once slept 6 hours or less daily but later increased their sleep duration to 7 to 8 hours had an increased risk for diabetes. They also experienced more weight gain than consistently short sleepers.
“Our results support the message that long-term maintenance of healthy sleep duration is a pillar of health and chronic disease prevention,” Cespedes noted. “However, simply increasing sleep duration after previous years of short sleep may not be a panacea.”