Does second-hand smoke associate with tooth loss among older Japanese? JAGES cross-sectional study

Second-hand smoke (SHS) is considered a risk factor for a number of oral diseases. However, its influence on tooth loss, which is the final consequence of periodontal disease and caries, remains unknown. We aimed to evaluate the association between SHS experience and the number of remaining teeth among non-smoking older Japanese individuals.

Cross-sectional data from the Japan Gerontological Evaluation Study (JAGES) 2013 were used. From the 27,561 people ≥65 years of age who responded to a self-reported questionnaire (response rate = 71.1%), data of 18,865 respondents who had never smoked were analysed. Multinomial logistic regression with multiple imputations was applied to estimate the odds ratio of the frequency of SHS exposures on the number of remaining teeth.

The prevalence of participants with ≥20 teeth, 10-19 teeth, 5-9 teeth, 1-4 teeth, and no teeth were 53.2%, 20.4%, 9.9%, 6.6%, and 9.9%, respectively. The proportion of participants with SHS was 37.5%. After adjusting for sex, the SHS experience tended to be associated with a lower risk of having the fewer number of remaining teeth (P < 0.05). However, after being adjusted for age and sex, participants with SHS exposure at "a few times a week" and "almost every day" were significantly associated with the fewer number of teeth. After adding all other covariates, compared to the participants without any exposure to SHS, the odds ratio for having no teeth rather than having ≥20 teeth among the participants with daily exposure to SHS was 1.35 (P < 0.01).

Daily second-hand smoke was significantly associated with fewer remaining teeth based on the self-reported survey among older Japanese people.