Modifiable risk factors for sleep apnea: evidence from meta-analysis of traditional observational studies and two-sample Mendelian randomization.

Abstract

Epidemiological studies have linked several modifiable factors to the risk of sleep apnea (SA). However, which specific factors affect the risk of SA and the strength of these effects are unclear. First, we conducted meta-analyses based on cross-sectional, cohort, and case-control studies published in PubMed, Scopus, and Web of Science, up to 1 Aug 2023. Studies that reported one of the associations of education level, physical activity, sedentary behavior, smoking status, alcohol consumption, and coffee consumption with SA were included. Two independent investigators assessed the risk of bias using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) Scale. The study protocol was prospectively registered with PROSPERO, CRD42022319988. Then, we performed two-sample Mendelian randomization (MR) studies to clarify the causality further. A total of 49 studies were included in the meta-analysis (total N =429,809). Compared with the other categorial groups, lower level of education (odds ratio (OR) 1.58, 95% confidence interval (CI) 1.28-1.96), higher level of sedentary behavior (1.22, 1.01-1.47), current smoking status (1.33, 1.17-1.51), current alcohol consumption (1.40, 1.33-1.48) were associated with higher risk of SA, and higher level of physical activity (0.77, 0.70-0.83) were associated with lower risk of SA. In the MR study, we found that years of educational attainment were associated with a lower risk of SA (0.83, 0.78-0.88), and that smoking initiation was associated with a higher risk of SA (1.10, 1.05-1.15). Prevention strategies of SA should focus on modifying these risk factors, especially reducing education inequalities and smoking initiation.