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

<b><i>Background:</i></b> 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. <b><i>Objectives:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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. <b><i>Conclusions:</i></b> 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.

**研究背景**：尽管已有证据表明日本民众的健康预期寿命有所提升，但现有估算均基于横断面调查数据中的患病率情况。**研究目标**：本研究采用多状态寿命表（multistate life table）法，针对1990年至2009年的两个纵向调查队列，计算基于发病的健康预期寿命指标，即活动预期寿命与非活动预期寿命（Life Expectancy，简称LE）。**研究方法**：本研究使用两项日本老年人纵向调查数据集：分别为1990–1999年的《日本老年人全国调查（National Survey of the Japanese Elderly）》与1999–2009年的《日本大学日本老龄化纵向研究（Nihon University Japanese Longitudinal Study of Aging）》。研究采用马尔可夫链插值法（Interpolation of Markov Chains），计算65岁人群在日常生活活动能力（activities of daily living, ADLs）或工具性日常生活活动能力（instrumental ADLs）方面存在困难与无困难状态下的剩余生存年数。**研究结果**：本研究发现，在10年研究周期内，65岁男女群体的活动预期寿命均出现显著提升；男性的总预期寿命以及女性的活动生命占比均发生显著变化；而非活动预期寿命在两个调查队列的研究周期内未出现显著改变。**研究结论**：本研究结果显示，在10年研究周期内，日本老年人的健康状况整体得到改善，其剩余寿命时长与活动状态下的生存时间均有所增加。该发现为日本老年群体的发病率压缩（compression of morbidity）现象提供了实证依据。