Estimating Health Expectancy in Japanese Communities Using Mortality Rate and Disability Prevalence.

ABSTRACT

Introduction: Although mortality and disability are known to be associated with health expectancy (LE), few studies have assessed the extent to which a reduction in their prevalence can extend a person's LE. Moreover, differences in this relationship based on gender have not been established. Thus, in this study, we constructed a regression model using the rate of mortality and prevalence of disability to predict LE in older adults (≥65 years) and assess the relationships between LE, mortality rate, and disability prevalence based on gender. Methods: Data were collected from Japan's population registry and long-term insurance records (N = 344). Multiple linear regression was used to analyze the relationship between LE, mortality rate, and disability prevalence, stratified by gender. Results: Age-adjusted mortality rate and disability prevalence significantly predicted LE and were significantly correlated with the measured LE index for both genders. For every 1% annual decrease in age-adjusted mortality, LE increased by 1.54 years for men and 2.15 years for women. Similarly, a 1% annual decrease in age-adjusted disability prevalence increased LE by 0.22 years for men and 0.32 years for women. The regression model coefficients indicated that the strength of the association between LE, mortality rate, and disability prevalence differed between genders. Our model accurately predicted LE (men adjusted R2 = 0.968, women adjusted R2 = 0.994). Conclusions: Health promotion policies that are geared toward increasing health expectancy can be evaluated using mortality rate and disability prevalence as prognostic indicators. The strength of the association between LE, mortality, and disability differed between genders, suggesting the need for gender-specific policy planning to increase LE for both genders.