Objective: To investigate the association between the sense of “life worth living (ikigai)” and the cause-specific mortality risk. The psychological factors play important roles in morbidity and mortality risks. However, the association between the negative psychological factors and the risk of mortality is inconclusive.
Methods: The Ohsaki Study, a prospective cohort study, was initiated on 43,391 Japanese adults. To assess if the subjects found a sense of ikigai, they were asked the question, “Do you have ikigai in your life?” We used Cox regression analysis to calculate the hazard ratio of the all-cause and cause-specific mortality according to the sense of ikigai categories.
Results: Over 7 years’ follow-up, 3048 of the subjects died. The risk of all-cause mortality was significantly higher among the subjects who did not find a sense of ikigai as compared with that in the subjects who found a sense of ikigai; the multivariate adjusted hazard ratio (95% confidence interval) was 1.5 (1.3–1.7). As for the cause-specific mortality, subjects who did not find a sense of ikigai were significantly associated with an increased risk of cardiovascular disease (1.6; 1.3–2.0) and external cause mortality (1.9; 1.1–3.3), but not of the cancer mortality (1.3; 1.0–1.6).
Conclusions: In this prospective cohort study, subjects who did not find a sense of ikigai were associated with an increased risk of all-cause mortality. The increase in mortality risk was attributable to cardiovascular disease and external causes, but not cancer.
CVD = cardiovascular disease; NHI = National Health Insurance; PHC = Public Health Center; IHD = ischemic heart disease; HR = hazard ratio; CI = confidence interval; BMI = body mass index.
From the Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
Address correspondence and reprint requests to Toshimasa Sone, Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Sendai 980-8575, Japan. E-mail: email@example.com
This study was supported by a Health and Labor Sciences Research Grants for Comprehensive Research on Aging and Health (H18-Choju-Ippan-014) from the Ministry of Health, Labor and Welfare, Japan (PI: I.T.).
Received for publication July 4, 2007; revision received February 27, 2008.