Sleep quality and psychological resilience: a cross-sectional study of community-dwelling adults in China.

OBJECTIVE: To examine the association between sleep quality and psychological resilience in a Chinese community-based cohort and assess the consistency of this association across two sleep measures. DESIGN: Cross-sectional analysis of baseline data. SETTING: Community-based cohort in Hangzhou, China (2016-2019). PARTICIPANTS: 10 268 adults aged 18-80 years enrolled via quota sampling stratified by sex and age group. After excluding participants with missing data, analytic samples were 9781 (single-item measure) and 9780 (Pittsburgh Sleep Quality Index (PSQI)), owing to one additional missing response. PRIMARY OUTCOME MEASURE: Low psychological resilience, defined by a median split on a 9-item scale adapted from the Brief Resilience Scale and Connor-Davidson Resilience Scale. RESULTS: Poor sleep quality was associated with higher odds of low resilience across both measures (single-item measure, adjusted OR=1.5, 95% CI 1.3 to 1.6; PSQI, adjusted OR=1.5, 95% CI 1.4 to 1.7), after adjustment for demographic factors, socio-economic factors, mental health indicators and health behaviours. Interaction tests showed no evidence of effect modification by sex, age group, loneliness or depression history for the single-item measure (p>0.05). For the PSQI, the association differed by loneliness (p<0.05), with a larger magnitude of association among lonely participants (adjusted OR=2.1, 95% CI 1.6 to 2.7) than non-lonely participants (adjusted OR=1.5, 95% CI 1.3 to 1.6). CONCLUSIONS: Poor sleep quality was consistently associated with low resilience across both measures. Because the design was cross-sectional, temporal direction cannot be established. Longitudinal and interventional studies are needed to establish temporal ordering, and intervention studies are needed to determine whether improving sleep increases resilience.