Association between frequency of laughter and oral health among community-dwelling older adults: a population-based cross-sectional study in Japan

Purpose Oral health has been reported to have an impact on the activities of daily life such as chewing, eating, and laughing, while psychological factors such as depression and loneliness have been reported to affect oral health. Little is known, however, about the association between laughter and oral health in older adults. This study examined the bidirectional association between the frequency of daily laughter and oral health in community-dwelling older Japanese adults. Methods Our cross-sectional study employed data from the 2013 Japan Gerontological Evaluation Study's self-reported survey, which included 11,239 male and 12,799 female community-dwelling independent individuals aged 65 years or older. We defined the oral health status by the number of remaining teeth. The association between the self-reported frequency of laughter (almost every day, 1-5 days per week, 1-3 days per month, or almost never) and oral health was examined using logistic regression analysis. Results The participants with 10 or more teeth were significantly more likely to laugh compared with the edentulous participants, after adjusting for all covariates. Compared with those who almost never laughed, those who laughed 1-5 days per week were significantly less likely to be edentulous. After stratifying by sex, similar results were found only in the men for both analyses. Conclusion There was a significant bidirectional association between frequency of laughter and oral health that was independent of socioeconomic and lifestyle factors among older adults.