Characteristics and correlates of sleep duration, daytime napping, snoring and insomnia symptoms among 0.5 million Chinese men and women

BACKGROUND: Inadequate sleep duration and insomnia can affect both physical and mental health. There is limited evidence, however, on characteristics and correlates of sleep patterns and insomnia in urban and rural China. METHODS: This cross-sectional study, involving 512,891 adults aged 30–79 years from ten (five urban and five rural) diverse areas in China, recorded detailed information, using interviewer-administered laptop-based questionnaires, on sleep patterns (duration, daytime napping and snoring) and insomnia symptoms. Logistic regression was used to examine the associations of sleep patterns and insomnia symptoms with a range of socio-economic, lifestyle, behaviour and health-related factors. RESULTS: Overall, the mean (SD) sleep duration was 7.38 (1.37) h, with 23% reporting short (≤6 h) and 16% reporting long (≥9 h) sleep duration, 21% taking daytime naps and 22% having frequent snoring. Overall, 17% reported having insomnia symptoms, with a higher proportion in women than in men (19% vs 13%), in rural than in urban residents (19% vs 15%), and in individuals who were living alone (23%). The adjusted odds ratios (ORs) of having insomnia symptoms were significantly higher among people with major depressive episodes (6.10, 95% CI: 5.69–6.55), generalised anxiety disorders (7.46, 6.65–8.37) and any chronic diseases (1.46; 1.44–1.49). In contrast, the ORs of insomnia symptoms were significantly lower among those reporting napping (0.77, 0.75–0.78) and frequent snoring (0.86, 0.84–0.87). CONCLUSIONS: Among Chinese adults, sleep patterns varied greatly by socio-economic, lifestyle and health-related factors. The risk of insomnia symptoms was associated with both poor mental and physical health status.