Environmental tobacco smoke exposure and periodontitis in non-smokers: a systematic review and meta-analysis

Previous studies on the association between environmental tobacco smoke (ETS) exposure and periodontitis and tooth loss in non-smokers have reported conflicting findings. This meta-analysis was therefore performed to provide a statistical summary of the evidence. A systematic literature search of PubMed, EMBASE, Web of Science, and the Cochrane Library was conducted for English-language publications published up to June 9, 2025. Odds ratio (OR) along with 95% confidence interval (95% CI) were used to analyze the main outcomes. A total of 14 studies composing 115,925 participants aged 18 years or older were included. A significant association was found between ETS exposure and periodontitis (OR = 1.47, 95% CI:1.22–1.76). However, null association was observed between ETS exposure and tooth loss (OR = 1.03, 95% CI: 0.80–1.31). Substantial heterogeneity was observed across studies. Subgroup analyses revealed stronger associations in studies using biomarker-based ETS assessment. Among non-smokers, exposure to ETS is significantly associated with periodontitis, underscoring the critical public health importance of reducing secondhand smoke exposure at the population level.