Differences in insulin secretion and sensitivity in short-sleep insomnia.

Objective: Short-sleep insomnia is associated with increased risk of diabetes. The role of altered insulin secretion and action in this association is poorly understood.

Design: Observational study.

Setting: Academic clinical research center.

Participants: Nondiabetic individuals with insomnia (mean [standard deviation] age 48 [9] y, body mass index 25.6 [3.9] kg/m(2)) with ≤ 6 h (short sleep, n = 14) and > 6 h of sleep (n = 14) during overnight laboratory polysomnography.

Measurements And Results: Standard oral glucose testing was used to assess glucose tolerance, beta-cell function (homeostasis model assessment [HOMA-B]; second-phase insulin secretion) and insulin resistance (HOMA-IR; insulin sensitivity index). There was no significant difference in hemoglobin A1C and fasting or 2-h blood glucose concentrations between sleep groups. Short-sleep insomnia sufferers had lower fasting and postchallenge serum insulin concentrations associated with lower estimates of fasting and glucose-stimulated insulin secretion, and increased insulin sensitivity.

Conclusions: Individuals with short-sleep insomnia appear to have higher indices of systemic insulin sensitivity and secrete less insulin without changes in overall glucose tolerance.