Changes in Health Expectancy for Older Adults in Japan: Results from Two Longitudinal Surveys.

Background: Although there is evidence of improvements in health expectancy among the Japanese population, existing estimates are based on the prevalence of morbidity taken from cross-sectional survey data.

Objectives: This study employed a multistate life table approach to compute incidence-based health expectancy measures, namely active and inactive life expectancy (LE), for two longitudinal survey cohorts from 1990 to 2009.

Methods: This study used data from two longitudinal surveys of older adults in Japan: the National Survey of the Japanese Elderly (1990-1999) and the Nihon University Japanese Longitudinal Study of Aging (1999-2009). We employed the Interpolation of Markov Chains technique to compute the number of years at age 65 years to be spent with and without difficulty in performing activities of daily living (ADLs) or instrumental ADLs.

Results: We documented significant increases in active LE for men and women at age 65 years over the 10-year study period. There were significant changes in total LE for men and in the percentage of active life for women. Inactive LE did not significantly change across the two survey cohorts during the study period.

Conclusions: Our results show that the health status of older adults in Japan has largely improved over the 10-year study period, with increases in both the duration of life and time spent in an active state. This finding offers evidence of compression of morbidity among older men and women in Japan.