Role of Sleep Duration As a Risk Factor for Type 2 Diabetes Among Adults of Different Ages in Japan: the Niigata Wellness Study

Aim: To compare the role of short sleep duration as a risk factor for diabetes among adults of different ages.

Methods: The study enrolled 38987 Japanese individuals without diabetes, and the 8-year risk of developing diabetes attributable to different sleep durations (< 5.5 h, 5.5 to < 6.5 h, 6.5 to < 7.0 h, 7.0-7.5 h, > 7.5-8.0 h, or > 8.0 h) was assessed among individuals aged ≤ 45, 46-59 or ≥ 60 years.

Results: During the 8-year follow-up period, 2085 individuals developed diabetes. Overall, individuals with a short sleep duration of < 5.5 h or 5.5 to < 6.5 h had, respectively, a 1.53-fold (95% CI 1.19, 1.97) or 1.25-fold (95% CI 1.10, 1.42) increased risk of diabetes as compared with those who had 7.0-7.5 h of sleep. A sleep duration of < 5.5 h or 5.5 to < 6.5 h was predictive of the development of diabetes among individuals aged ≤ 45 years, but not among those aged ≥ 60 years. With increasing age, the effect of short sleep duration on the risk of diabetes was attenuated.

Conclusions: Short sleep duration was predictive of diabetes among young or middle-aged Japanese adults but not among elderly individuals after age was considered. Managing habitual short sleep and the possible reasons for having such short sleep duration could be particularly important for young or middle-aged adults in the development of future diabetes.