Association of second-hand smoking with sleep quality among adults in Ibadan, Nigeria: a cross-sectional evaluation of data from the COMBAT-CVDs study.

Purpose: Sleep quality (SQ) is essential in the overall well-being and quality of life, but little is known about the association of secondhand smoking (SHS) with SQ. This study assessed the relationship between SHS and SQ among adults who had never smoked in Ibadan, Nigeria.

Methods: We identified 3193 respondents who had never smoked or used any form of tobacco product in the Community-based Investigation of the Risk Factors for Cardiovascular Diseases in the Ibadan and suburbs (COMBAT-CVDs) study. SHS was self-reported, SQ assessed using a sleep quality scale, and SQ scores were classified by the quartile distributions of SQ scores in this sample as good (< 7), moderate (7-13), fair (14-20), and poor (≥ 21), and logistic regression models were used to estimate the multivariable-adjusted odds ratio and 95% confidence interval (CI) of the association between SHS and SQ in a two-sided test at P < 0.05.

Results: The mean (SD) of age in this sample was 34.8 ± 15.1 years; 1621 (50.8%) were females, and 848 (26.6%) experienced SHS. The multivariable-adjusted odds by categories of SQ scores (using good SQ as reference) in the light of SHS were OR: 1.64 (95%CI 1.28, 2.12) for moderate SQ, OR: 1.88 (95%CI 1.46, 2.42) for fair SQ and OR: 2.14 (95%CI 1.66, 2.75) for poor SQ; P < 0.0001 after adjusting for relevant covariates. The sex- and age groups- stratified analyses revealed similar trends.

Conclusion: SHS is associated with higher odds of poor SQ in this study. Culturally relevant interventions for mitigating exposure to SHS might improve SQ and overall quality of life, particularly among vulnerable populations.