Forecasting Trends in Disability in a Super-Aging Society: Adapting the Future Elderly Model to Japan

Japan has experienced pronounced population aging, and now has the highest proportion of elderly adults in the world. Yet few projections of Japan’s future demography go beyond estimating population by age and sex to forecast the complex evolution of the health and functioning of the future elderly. This study adapts to the Japanese population the Future Elderly Model (FEM), a demographic and economic state-transition microsimulation model that projects the health conditions and functional status of Japan’s elderly population in order to estimate disability, health, and need for long term care. Our FEM simulation suggests that by 2040, over 27 percent of Japan’s elderly will exhibit 3 or more limitations in IADLs and social functioning; almost one in 4 will experience difficulties with 3 or more ADLs; and approximately one in 5 will suffer limitations in cognitive or intellectual functioning. Since the majority of the increase in disability arises from the aging of the Japanese population, prevention efforts that reduce age-specific disability (or future compression of morbidity among middle-aged Japanese) may have only a limited impact on reducing the overall prevalence of disability among Japanese elderly.