Demographic and socioeconomic inequalities in sleep quality among Chinese aged 15 years and above: a national population-based study.

Background: High-quality sleep is essential for health, yet sleep patterns and their prevalence within the Chinese population remain inadequately characterized. We aimed to estimate the prevalence of poor sleep quality and various sleep characteristics within China, and to explore the social gradients and inequalities in sleep quality to identify vulnerable populations. Methods: For this nationally representative cross-sectional study, we recruited 46,452 community-based Chinese individuals aged 15 years or older from 420 communities (villages) using a multistage, stratified, cluster-randomized sampling design that considered geographic region, sex and age distribution. Face-to-face questionnaire interviews were conducted to collect self-reported data on demographic characteristics, socioeconomic status, Pittsburgh Sleep Quality Index (PSQI) responses, lifestyle factors, and current chronic disease status. We calculated the prevalence of poor sleep quality (PSQI > 5) and various sleep parameters, as well as analyzed their distribution across various demographic and socioeconomic characteristics. Multivariable logistic regression models were applied to identify factors associated with poor sleep quality in the national sample and by age stratum. Findings: Among Chinese individuals aged 15 years and above, the weighted prevalence was 23.9% (95% CI 21.6-26.2) for poor sleep quality under the PSQI > 5 cutoff threshold, along with prevalence of 53.7% (95% CI 49.8-57.6) for reported sleep disturbances and 1.6% (95% CI 1.3-1.9) for use of hypnotic medication. The weighted mean was 27.5 min (95% CI 26.4-28.5) for sleep latency and 7.2 h (95% CI 7.2-7.3) for sleep duration. Multivariable analysis revealed that the likelihood of poor sleep quality was significantly associated with female sex (odds ratio 1.58 [95% CI 1.37-1.82]), advanced age (45-54 years: 1.56 [1.10-2.23]; 55-64 years: 2.06 [1.43-2.96]; ≥65 years: 2.39 [1.68-3.40]), lower household income (50,000-100,000 Chinese yuan [CNY]: 1.25 [1.07-1.46]; 100,000-200,000 CNY: 1.33 [1.01-1.75]), lower education level (junior high school: 0.84 [0.76-0.92]; high school: 0.78 [0.67-0.91]; university: 0.65 [0.54-0.77]), and occupation (government institution employee: 1.89 [1.31-2.73]; unemployed: 1.22 [1.01-1.46]). Women demonstrated significantly higher weighted prevalence of poor sleep quality compared to men. Beginning at age 25, the sex gap of poor sleep quality prevalence progressively widened from 5.2% (95% CI 0.9-9.6) in the 25-34 years age group to 14.3% (95% CI 10.2-18.4) among those aged 65 and older, with escalating statistical significance (P = 0.02 to P < 0.001). No statistically significant associations were found between residence location and the prevalence of poor sleep quality (P > 0.05). The factors associated with poor sleep quality were largely similar across age groups, with several important differences. Higher household income was associated with poorer sleep quality only among adults under 45 years of age (10,000-30,000CNY: 1.50 [1.01-2.20]; 30,000-50,000CNY: 1.40 [1.02-1.91]; 50,000-100,000 CNY: 1.83 [1.38-2.42]; 100,000-200,000 CNY: 2.07 [1.35-3.17]). Government employees under 60 years had higher odds of poor sleep quality (<45 years: 2.45 [1.52-3.94]; 45-60 years: 1.94 [1.21-3.10]), whereas medical personnel aged 60 and above had significantly lower odds (0.14 [0.04-0.56]). Geographically, residents in central China had significantly lower odds of poor sleep quality than those in eastern regions among adults aged 45-60 years (0.83 [0.70-0.99]). Interpretation: Poor sleep quality demonstrates remarkably high prevalence across China, with demographic and socioeconomic factors serving as key determinants of sleep health disparities. These findings underscore the urgent need for comprehensive, targeted interventions that address the underlying social and economic drivers of sleep inequality to enhance population sleep health nationwide. Funding: Chinese Sleep Research Society, the General Program of the National Natural Science Foundation of China.