Dai F, et al. - The association between sleep duration and the incidence of diabetes stratified by sleep-related factors among Chinese men was evaluated. The researchers proposed that longer sleep duration was correlated with diabetes, particularly among individuals already exhibiting factors linked to poor quality of sleep. The relationship between sleep duration and diabetes could be modified by tea drinking, particularly in older men or men with more sleep-related factors.

• From 2002 to 2011, the researchers enrolled 34,825 men who provided information on sleep-related questions in the Shanghai Men’s Health Study, a population-based cohort study conducted in Shanghai, China.
• They excluded participants who had a history of diabetes or who were diagnosed with diabetes within 2 years of recruitment.
• They employed Cox regression to assess the influence of sleep duration and its interaction with sleep-related factors on diabetes risk.

• During a median of 5.6 follow-up years, 1521 incident cases were documented.
• For men who slept <7 and ≥8 hours per day, adjusted hazard ratios and 95% confidence intervals were 1.0 (0.9-1.1) and 1.2 (1.0-1.3), respectively, compared with those who slept 7 hours per day (ptrend=0.01).
• Stratified analyses demonstrated that the relationship between sleep duration and risk of diabetes was only statistically significant among current smokers and regular drinkers, never tea drinkers, men with a high body mass index, hypertension or comorbidity, and men who did not work nightshift or who snored.
• The researchers observed a statistically significant interaction between tea drinking and sleep duration (p_interaction=0.01).
• When daytime nappers were excluded from the analyses, the above association patterns remained.