Gender-specific independent and combined dose-response association of napping and night sleep duration with type 2 diabetes mellitus in rural Chinese adults: the RuralDiab study.

OBJECTIVE: The aim of this study was to explore the independent and combined dose-response association of napping and night sleep duration with type 2 diabetes mellitus (T2DM) among different genders in the rural Chinese population.

METHODS: For this research, a total of 19,257 participants were enrolled in the Rural Diabetes, Obesity and Lifestyle (RuralDiab) study. Napping and night sleep duration were assessed using the Pittsburgh Sleep Quality Index (PSQI). Restricted cubic splines and logistic regression were used to estimate the relationship between napping and night sleep duration with T2DM.

RESULTS: A linear dose-response relationship between napping duration and T2DM as well as a U-shaped relationship between night sleep duration and T2DM were found. Compared with those who reported no napping, participants who had a napping duration of ≥91 min were associated with a 19% increase in prevalence of T2DM. Adjusted odds ratios (ORs) (95% confidence intervals (CIs)) for T2DM were 1.48 (1.03, 2.14) and 1.50 (1.22, 1.85) for shorter (≤5 h) and longer (>9 h) night sleep duration compared with the referential group. Additionally, the combination of longer napping duration (≥91 min) and night sleep duration (>9 h) increased 104% (95% CI: 45%, 128%) prevalence for T2DM. These associations were not found in males but were evident in females.

CONCLUSIONS: Longer napping duration and extreme night sleep duration increased the prevalence of T2DM. Meanwhile, longer napping and night sleep duration might be jointly associated with a higher prevalence of T2DM.