Factors affecting subjective health of child-rearing-aged Japanese adults, considering the effect of healthy life expectancy: A cross-sectional study

OBJECTIVES: The extension of healthy life expectancy is an important policy issue in Japan. This study aimed to clarify the association between subjective health and healthy life expectancy and identify the factors that improve subjective health of child-rearing-aged adults in Japan. METHODS: A cross-sectional study was conducted. We used data from 2718 participants of the Japanese General Social Survey 2009 Life Course Study. The mean age was 35.5 ± 4.10 years, and 56% were female. Multivariate logistic regression analysis was performed on subjective health, which was treated as a binary variable when calculating healthy life expectancy as an objective variable. The predictors were gender, age, marital status, number of family members living in the home, household income, mental health score, age of youngest child, and the person from whom one seeks help. The prefecture where the participants resided was treated as a control variable. RESULTS: There was no association between individual subjective health and healthy life expectancy. Mental health score (measured by the Mental Health Inventory-5, MHI-5) was significantly associated with subjective health. With a MHI-5 score of ⩽ 10 points as the reference criterion, as the score increased, the odds ratio of subjective health increased, and for MHI-5 scores ⩾ 16 points, odds ratio was 14.14 (confidence interval: 7.57–26.38). CONCLUSION: Among the child-rearing-aged adults, prefectural healthy life expectancy was not associated with individual subjective health. Mental health was significantly associated with subjective health and may be underestimated in calculating healthy life expectancy.