Background: Positive and negative psychological factors are associated with mortality and cardiovascular disease. This study prospectively investigated associations between daily frequency of laughter, and mortality and cardiovascular disease in a community-based population.
Methods: This study included 17,152 subjects ≥40 years old who participated in an annual health check in Yamagata Prefecture. Self-reported daily frequency of laughter was grouped into 3 categories (≥1/week; ≥1/month but <1/week; <1/month). Associations between daily frequency of laughter and increase in all-cause mortality and cardiovascular disease incidence were determined using Cox proportional hazards modeling.
Results: During follow-up (median, 5.4 years), 257 subjects died and 138 subjects experienced cardiovascular events. Kaplan-Meier analysis revealed that all-cause mortality and cardiovascular disease incidence were significantly higher among subjects with a low frequency of laughter (log-rank P<0.01). Cox proportional hazard model analysis adjusted for age, gender, hypertension, smoking, and alcohol drinking status showed that risk of all-cause mortality was significantly higher in subjects who laughed <1/month than in subjects who laughed ≥1/week (hazard ratio (HR) 1.95, 95% confidence interval (CI), 1.16-3.09). Similarly, risk of cardiovascular events was higher in subjects who laughed ≥1/month but < 1/week than in subjects who laughed ≥1/week (HR 1.62, 95% CI, 1.07-2.40).
Conclusion: Daily frequency of laughter represents an independent risk factor for all-cause mortality and cardiovascular disease in a Japanese general population.