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 estimates a new state-transition microsimulation model - the Japanese Future Elderly Model (FEM) - for Japan. We use the model to forecast disability and health for Japan's future elderly. Our 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 morbidity can help reduce the burden of disability but may have only a limited impact on reducing the overall prevalence of disability among Japanese elderly. While both age and morbidity contribute to a predicted increase in disability burden among elderly Japanese in the future, our simulation results suggest that the impact of population aging exceeds the effect of age-specific morbidity on increasing disability in Japan's future.

中文翻译：

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预测超级老龄化社会中的残疾趋势：将未来的老年人模型适应日本。

日本经历了明显的人口老龄化，现在是世界上老年人口比例最高的国家。然而，对于日本未来人口统计学的预测，除了按年龄和性别估算人口之外，还不能预测未来老年人健康和功能的复杂变化。这项研究为日本估算了一种新的状态转换微观模拟模型-日本未来老年人模型（FEM）。我们使用该模型预测日本未来老年人的残疾和健康状况。我们的模拟结果表明，到2040年，超过27％的日本老年人在IADL和社会功能方面将表现出3个或更多限制；几乎四分之一的人会遇到3个或更多ADL的困难；大约五分之一的人会在认知或智力功能上受到限制。由于残疾的增加大部分来自日本人口的老龄化，因此，减少特定年龄段发病率的预防措施可以帮助减轻残疾负担，但对降低日本老年人的总体残疾患病率可能仅产生有限的影响。尽管年龄和发病率都可以预测将来日本老年人的残疾负担增加，但我们的模拟结果表明，人口老龄化的影响超过了特定年龄段发病率对日本未来残疾增加的影响。