Association between prenatal or postpartum exposure to tobacco smoking and allergic rhinitis in the offspring: An updated meta-analysis of nine cohort studies

Introduction Previous studies have suggested an association between tobacco smoke exposure and allergic rhinitis. This study aimed to investigate if prenatal or postpartum smoke exposure will increase the risk of allergic rhinitis in offspring. Methods PubMed, EMBASE, and the Cochrane library were searched from inception to July 2020 for eligible studies investigating the association between smoking exposure and allergic rhinitis. The random-effects model was adopted for the metaanalysis to obtain the summary odds ratio (OR) with a 95% confidence interval (CI). Subgroup analysis based on the age of children was performed. Sensitivity analysis was carried out to check the robustness of the results. Publication bias of included studies was assessed. Results This meta-analysis included nine studies, in which six studies suggested that children exposed to prenatal smoking were more likely to develop allergic rhinitis compared with children who were never exposed (OR=1.12; 95% CI: 1.04–1.21). The subgroup analysis divided children those aged 10 years (OR=0.99; 95% CI: 0.82–1.20). This metaanalysis revealed a positive relationship between postpartum smoke exposure and the development of allergic rhinitis in offspring (OR=1.19; 95% CI: 1.03–1.39) with marked heterogeneity. The subgroup analysis of age in the postnatal group showed similar results in children aged >10 years (OR=1.17; 95% CI: 1.05–1.30) and children aged