Healthy Aging: IADL and Functional Disability

Abstract

Extension of healthy life expectancy is an important topic in Japanese healthy aging policy, which has already achieved extended life expectancy. In 2013, there was about a 9-year gap between life expectancy and healthy life expectancy among men, and a 13-year gap of them among women. Although the definition of healthy life expectancy is diverse, one definition is measured by a period that has not seen the onset of functional disability in public long-term care certification, or that has independence in instrumental activities of daily living (IADL; a higher-living functional capacity of older adults). About 18% of older adults were certified for long-term care/support needs, and the number was about 5.9 million people (as of 2014).Many studies indicate that the ability to conduct IADL, the onset of functional disability, and death are intimately related to not only lifestyles and health behaviors, but also to socioeconomic situations. While several systematic reviews focusing on the daily functions of older adults exist [1-3], overseas findings are not necessarily applicable to Japan because of genetic, environmental, and cultural factors. There is thus a need to review findings on older adults in Japan. Longitudinal studies are needed when doing so because there is a bidirectional relationship between health and other variables (for example, the unhealthier one is, the harder it is to acquire income; the poorer one is, the easier it is to become unhealthy). As opposed to cross-sectional studies, which are based on synchronic data, longitudinal studies trace individuals. Furthermore, considering that there are few cases in which Masashige Saito is also the English translator for this chapter.