Passive smoking is associated with poor carious status in adults: A population-based cross-sectional study

To explore the association between passive smoking and dental caries and its potential mechanism.

Totally, 5759 participants from the National Health and Nutrition Examination Survey 2011-2018 were included. Overlap weight was applied to facilitate causal inference. Weighted generalized linear regression models were used to examine the relationship between the number of household smokers and dental caries, including decayed, missing, and filled teeth (DMFT), tooth surfaces (DMFS), and tooth count. Mediation analysis was conducted to explore the potential role of ever-smoking in this relationship. Sensitivity analyses were performed to validate the findings.

Weighted generalized linear regression revealed that, compared with non-smokers, ever-smokers had 2.6 less teeth (95 % CI = -3.2, -2.1, P < 0.001), 1.7 higher DMFT (95 % CI = 1.1, 2.4; P < 0.001), and 7.4 higher DMFS (95 % CI = 5.1, 9.7; P < 0.001). Living with smokers was significantly associated with -2.4 less teeth (95 % CI = -3.2, -1.6; P < 0.001), 0.77 higher DMFT (95 % CI = 0.02, 1.5; P = 0.045), and 3.4 higher DMFS (95 % CI = 0.89, 5.9; P = 0.009). Mediation reveals that ever-smoking behavior may explain 17.9 %, 53.0 %, and 43.8 % of the effect of living with smokers on tooth loss, DMFT, and DMFS respectively, indicating that the influence of household smoking on dental caries is partly mediated through its impact on individuals' propensity to engage in smoking.

This study suggests that passive smoking from household members is associated with greater tooth loss and caries experience in adults. Mediation analysis further indicates that differences in ever-smoking behavior may partially account for these associations.

These findings emphasize the importance of smoke-free homes and early prevention to protect long-term oral health.