Abstract
AIM: Tobacco smoke exposure, zinc intake, and periodontitis are closely related. This study intended to assess the relationship between tobacco smoke exposure and zinc intake and its effect on periodontitis. MATERIALS AND METHODS: This cross-sectional study included 9364 participants from the National Health and Nutrition Examination Survey (NHANES) of USA. A weighted multivariate logistic regression model was used to investigate the independent relationship and interaction effect among tobacco smoke exposure, zinc intake, and periodontitis. Odds ratio (OR) with 95% confidence interval (CI) was calculated. The additive interaction was evaluated using relative excess risk due to interaction (RERI), attributable proportion of interaction (AP), and synergy index (SI). RESULTS: In all, 56.57% participants had periodontitis. Compared with participants without tobacco smoke exposure, those with tobacco smoke exposure had increased odds of having periodontitis (OR, 1.96; 95% CI, 1.67-2.31). Similarly, patients with adequate zinc intake were found to have decreased odds of having periodontitis than those with inadequate zinc intake (OR, 0.86; 95% CI, 0.76-0.98). Importantly, there was antagonistic interaction effect between zinc intake and tobacco smoke exposure on periodontitis (RERI: OR, -0.432; 95% CI, -0.829 to -0.034; AP: OR, -0.242; 95% CI, -0.470 to -0.014; SI: OR, 0.645; 95% CI, 0.446 to 0.932). CONCLUSIONS: Tobacco smoke exposure and zinc intake were independently correlated with periodontitis risk. Decreasing tobacco smoke exposure and optimizing dietary zinc intake appear to be important measures that could be taken to control periodontitis.