Background: Many studies have focused on disease causality, but few of them deal with health-promoting factors. Thus, we examined the effect of having a sense of purpose in life (ikigai) on mortality from cardiovascular disease (CVD).
Methods: In 1988, we conducted a prospective cohort study of 2,959 Japanese subjects, ranging in age from 40 to 74 years, and followed them till the end of 2003. The level of their sense of purpose in life was evaluated by a self-administered questionnaire. After excluding those with a history of heart disease, stroke, or malignant tumor, 1,618 subjects (832 men and 786 women) who had completed the questionnaire were used in the analyses with Cox's proportional hazards model.
Results: During the average 13.3 years of follow up, 249 deaths (172 men and 77 women) occurred as a result of all causes: 32 from heart disease, 31 from stroke, 63 from CVD, and 104 from malignant tumors. The adjusted hazard ratios for death in men with a strong sense of purpose in life, as compared with those with a low sense of purpose, were 0.28 (95% confidence interval: 0.10-0.84) for stroke, 0.56 (0.28-1.10) for CVD, and 0.62 (0.45-0.86) as a result of all causes. In women, no significant relationship was found between having a sense of purpose in life and mortality; this was possibly because the smaller number of deaths reduced the statistical significance.
Conclusion: We found that in men, having a sense of purpose in life affected the risk of death as a result of all causes, stroke, and CVD.