Does laughing with others lower the risk of functional disability among older Japanese adults? The JAGES prospective cohort study.

While laughter is evoked mainly in social contexts, the potential link between laughter in daily life and health benefits is unclear. This study aimed to examine the association between laughter in daily life and the onset of functional disability among older adults in Japan. Data were obtained from a 6-year follow-up cohort of 12,571 participants (46.1% male) in the Japan Gerontological Evaluation Study, aged ≥65 years, who could independently perform daily activities. We evaluated their laughter in daily life from three perspectives: the types of situations in which people laugh, the number of situations in which people laugh with others, and the persons with whom people laugh. Using the Cox proportional hazards model, the risk of functional disability was estimated. A total of 1420 functional disabilities were observed during follow-up. After adjusting for potential confounders, participants who laughed with others (e.g., during conversations with friends) were at a reduced risk of functional disability (hazard ratio, 0.77; 95% confidence interval, 0.65-0.92) than those who laughed alone (e.g., during watching television). Similarly, the number of situations to laugh with others was inversely associated with the risk of functional disability (P < 0.001). Laughing in a conversation with friends reduced the risk of functional disability by approximately 30% compared to laughing alone. Overall, laughing with others was associated with a reduced risk of functional disability. Having more situations to laugh with others or at least the situation to laugh with friends might contribute to reducing the risk of functional disability later in life.