Secondhand smoke is associated with poor sleep quality in self-reported never-smokers of Northwest China: a cross-sectional study.

Abstract

To investigate the relationship between secondhand smoke (SHS) exposure and sleep quality in never-smokers of Northwest China. Never-smoking adults (≥ 15years) from Xinjiang, Northwest China, were included in this cross-sectional survey between April and October 2019. SHS exposure in never-smokers was estimated using a structured questionnaire. Sleep quality was evaluated by Pittsburgh Sleep Quality Index (PSQI), with PSQI score > 5 classified as poor sleep quality. Association of SHS exposure and frequency and duration of SHS exposure with poor sleep quality were analyzed by using a multivariate logistic regression after adjusting for potential confounding factors, including stratification by sex. The mean age of participants was 48.0years, and 77% were females. Of 21,198 never-smokers, 13% (n = 2703) reported SHS exposure and 35% (n = 7390) reported poor sleep quality. In multivariate logistic regression analysis, a significant association was observed between SHS exposure and poor sleep quality (adjusted odds ratio (OR), 1.36; 95% confidence interval (CI)1.24-1.48). Subgroup analysis showed a negative association of SHS exposure with sleep quality in both sexes. However, a significant dose-response relationship of frequency and duration of SHS exposure per week with poor sleep quality was observed only in females. Consistent results were also observed in the aged ≥ 18years. Exposure to SHS is associated with poor sleep quality in never-smoking adults of Northwest China. A dose-response relationship between SHS exposure and poor sleep quality is found in women. Avoiding SHS exposure may have beneficial effects on sleep quality, especially for females.