Risk of type 2 diabetes in patients with insomnia: A population‐based historical cohort study

BACKGROUND: We investigated the risk of type 2 diabetes mellitus (T2DM) in patients with and without insomnia. METHODS: In this historical cohort study, we performed a secondary analysis of data from 2001 to 2010, which was obtained from Taiwan's National Health Insurance Database. We developed a Cox proportional hazard regression model to estimate the effects of insomnia on T2DM risk. Kaplan-Meier survival analysis was applied to compare the differences in the cumulative incidence of T2DM between the groups with and without insomnia. RESULTS: During the follow-up period, the T2DM incidence rate of patients with insomnia was significantly higher than that of patients without insomnia (34.7 vs 24.3 per 1000 person-years). Overall, patients with insomnia had a higher risk of T2DM than did patients without insomnia (adjusted hazard ratio, 1.16; 95% confidence interval CI, 1.10-1.19). Among patients aged younger than 40 years, those with insomnia had a higher risk of T2DM than did the comparison cohort (adjusted hazard ratio, 1.31; 95% CI, 1.14-1.55). Compared with patients without insomnia, the risk tended to increase with the duration of follow-up in patients with insomnia; when the insomnia duration was 8 years, the risk of T2DM increased by 1.14, 1.38, and 1.51 times (95% CI, 1.03-1.17, 1.15-1.49, and 1.20-1.86), respectively. Patients with insomnia had a higher risk of T2DM, and this risk was particularly pronounced among the younger (≤40 years) population. CONCLUSION: Chronic insomnia could be an important risk factor for T2DM.