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.