A comparison of correlates of self-rated health and functional disability of older persons in the Far East: Japan and Korea
Introduction
With population aging emerging as a worldwide phenomenon, researchers and policy makers are increasingly turning to cross-national research to better understand the health of the nation's older population. For scientists comparative analysis using nation-level data enhances understanding of differentials in health status among nations and the dynamics of population aging and its impact on health and health care. It is also useful in assessing the generalizability of findings and validity of interpretations across diverse cultural settings (Liang and Jay, 1992). Cross-national comparisons of population health, if done appropriately, may also aid policy makers in evaluating the performance of the nation's health care system (Kovar et al., 1995, World Health Organization, 2000) and facilitate the development of effective policies and programs that promote the health of older people (National Research Council, 2001).
Most cross-national research on aging and health reported thus far, however, have been largely based on comparisons of Western populations or have looked at ethnic groups within a specific country. Relatively few research exist that have examined health status of elderly populations in Asia, where the growth in the number and proportion of older persons is found to be one of the fastest among the world's major regions (Myers, 1990).
Countries in East and Southeast Asia, in particular, are aging most rapidly (Kinsella and Velkoff, 2001). In the Far Eastern part of the region, Japan and Korea top the rank in the rate of population aging. Japan is one of the world's foremost aged societies, with over 17% of the population being aged 65 and older in 2000. It took Japan 26 years, from 1970 to 1996, for its 65+ percentage to double from 7 to 14%. In comparison, Korea still has a relatively young population composition, with 7.2% of the population in the 65+ age stratum (National Statistical Office, 2001). Recent projections, however, indicate a faster aging rate than in Japan, with an estimated period of 19 years to reach 14% by the year 2019. The pace at which population aging is progressing in these two countries is alarming compared with that of Western nations. The 7–14% rise in the 65+ population occurred over a period of 115 years (1864–1979) in France and is expected to take 69 years (1944–2013) in the United States.
Moreover, previous efforts at comparisons between the nation's elderly have largely focused on gross indicators of health, such as morbidity and mortality. Although important, these measures do not reflect the older individual's perspectives on his or her overall health. They further fail to encompass physical functioning, an important indicator of the ability for older persons to maintain independence in the community; also increasingly being recognized as a ‘vital sign’ for geriatric care (Bierman, 2001).
Self-reports of health, in terms of self-rated health and physical functioning, are key indicators of health and well-being of older adults. They provide valid information as to the older person's general health status and dependency or care needs. Being simple in form and easy to administer through questionnaires or interviews, these person-centered measures complement more ‘objective’ assessments performed in the doctor's office. These perceptions about one's health and functional capacity, moreover, are significantly associated with adverse health outcomes of aging. Studies of older persons have found self-rated health and physical functioning to be highly correlated with chronic diseases or symptoms (Mulsant et al., 1997, Woo et al., 1998, Fried et al., 1999, Bryant et al., 2000), hospitalization (Mor et al., 1994, Kennedy et al., 2001), functional decline or disability (Mor et al., 1994, Idler and Kasl, 1995, Lawrence and Jette, 1996, Lee, 2000), and mortality (Idler and Benyamini, 1997, Scott et al., 1997, Lee, 2000).
Until now, there have been very few cross-national comparisons examining the correlates of self-rated health and physical functioning of older people (Liang et al., 1991, Kovar et al., 1995, Lamb, 1996, Jylhä et al., 1998). And to our knowledge, there has been no comparisons done using national samples of older populations in Far East Asia. Findings of similarities in the structure of these measures, in regard to their associated factors, would enhance the generalizability of results of existing research and support their utility as a comparative health assessment tool in this regional setting. In this study, using national surveys, we examined patterns of associations between self-rated health and functional disability and sociodemographic and health-related correlates among older persons in Japan and Korea.
Section snippets
Data sources
Two nationwide surveys of community-dwelling older persons aged 60 years and over were used in the comparisons: the 1987 National Survey of the Japanese Elderly and the 1994 Survey on the Living Status of the Korean Elderly. The Japanese survey used a two-stage probability sampling design (Jay et al., 1993, Liang and Maeda, 1997). In the first stage, out of the 780 000 census enumeration districts from the 1985 census, stratified by geographic region and city size, 192 primary sampling units
Results
The distribution of sociodemographic characteristics of the respondents shows significant inter-country differences (Table 1). The Korean older people, compared with their Japanese counterpart, tended to be younger on average (68.2±6.4 vs. 69.2±6.8) and have a higher percentage of females (60 vs. 55%). More Koreans than Japanese were not married, living alone, or dwelling in rural regions. A particularly large difference was observed in education, in which 3/4 of elderly Japanese had 7 or more
Discussion
This study compared correlates of self-rated health and functional disability of older adults between the two countries in Far East Asia. The results show significant differences in the distribution of self-reports between the cultures. Overall, the Korean elderly tended to rate their health to be worse and report more limitations in physical functioning than did the Japanese elderly. Such variations in self-assessments of health and disability were found to be consistent across different
Acknowledgements
This study was initiated when the author (Y. Lee) was a visiting scientist at the Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan. The authors would like to thank the Korea Institute for Health and Social Affairs (KIHASA), Seoul, Korea and the National Archive of Computerized Data on Aging (NACDA), Ann Arbor, MI, USA for providing the datasets. We also would like to thank two anonymous reviewers for their helpful comments.
References (47)
- et al.
‘Mini-mental state’. A practical method for grading the cognitive state of patients for the clinician
J. Psychiatr. Res.
(1975) - et al.
Association of comorbidity with disability in older women: the Women's Health and Aging Study
J. Clin. Epidemiol.
(1999) A cross-national study of quality of life factors associated with patterns of elderly disablement
Soc. Sci. Med.
(1996)- et al.
Transitions in cognitive status among the aged in Japan
Soc. Sci. Med.
(1996) - et al.
Functional health status as a predictor of mortality in men and women over 65
J. Clin. Epidemiol.
(1997) - et al.
Cross-cultural differences in the reporting of global functional capacity. An example in cataract patients
Med. Care
(1998) Functional status. The sixth vital sign (editorial)
J. Gen. Intern. Med.
(2001)Back-translation for cross-cultural research
J. Cross Cult. Psychol.
(1970)- et al.
Factors that contribute to positive perceived health in an older population
J. Aging Health
(2000) - et al.
Aging and perceived health status
J. Gerontol.
(1983)
Self-ratings of health among the old and the old–old
J. Health Soc. Behav.
Self-rated health as a predictor of active life in the community elderly
J. Epidemiol.
Age differences in self-assessments of health: age changes, cohort differences, or survivorship
J. Gerontol. B Psychol. Sci. Soc. Sci.
Self-rated health and mortality: a review of twenty-seven community studies
J. Health Soc. Behav.
Self-ratings of health: do they also predict change in functional ability?
J. Gerontol. B Psychol. Sci. Soc. Sci.
Patterns of nonresponse in a national survey of elderly Japanese
J. Gerontol. B Psychol. Sci. Soc. Sci.
Is self-rated health comparable across cultures and genders?
J. Gerontol. B Psychol. Sci. Soc. Sci.
Behavioral, social, and socioeconomic factors adding years to life and life to years
Repeated hospitalizations and self-rated health among the elderly: a multivariate failure time analysis
Am. J. Epidemiol.
An Aging World: 2001, Series P95/01-1
Two shorter forms of the CES-D depression symptom index
J. Aging Health
Prevalence of disability among older people: United States and Canada
Vital Health Stat.
Cited by (89)
Healthy but unhappy? Cross-national comparative analysis of depressive symptoms in Japanese vs. Korean elders
2021, Archives of Gerontology and GeriatricsSocioeconomic disparities in self-rated health in two East Asian countries: Comparative study between Japan and Korea
2020, Social Science and MedicineGender inequalities in poor self-rated health: Cross-national comparison of South Korea and Japan
2020, Social Science and MedicineDoes subjective health matter? Predicting overall and specific ADL disability incidence
2020, Archives of Gerontology and GeriatricsQuality of Life in Elderlies: A Cross-Sectional and Field-Based Study in Iran
2023, Shiraz E Medical Journal
- 1
Tel.: +81-3-3964-3241; fax: +81-3-3579-4776.