Introduction The importance of positive emotion to our health has been recognised and an increasing number of studies have examined the association between positive emotion and health. The value of experience laughter has been receiving attention recently. The aim of this study was to examine the association between frequency of laughter (FOL) and subsequent disability in community-dwelling elderly in Japan.

Methods A 1-year prospective study was conducted among 162 community-dwelling people aged 65 years and older who participated in annual health check-ups for the community's elderly and confirmed to have no disability in performing activities of daily living (ADL) at baseline interview. Measures included functional ability, sociodemographic and psychological factors, medical conditions, and self-ratings of frequency of laughter (FOL). OR and 95% CI of functional disability 1 year later in relation to the low-level of FOL vs higher levels of FOL were calculated using logistic regression models.

Results Low-level FOL at baseline was significantly related to functional disability 1 year later in univariate analyses (OR 5.78, 95% CI 2.03 to 16.51). In multivariate analyses, low FOL was also significantly correlated with functional disability, even after controlling for sociodemographic variables, psychological factors, and medical conditions.

Conclusion Our findings suggest that low frequency of laughter is associated with functional decline in community-dwelling elderly in Japan.