Demographers and social gerontologists have long recognized that population ageing, a growth in the number and proportion of older persons within a population, is occurring in many parts of the world

Using data from the Survey of Health and Living Status of the Elderly in Taiwan, we investigate changes in difficulties in walking and climbing stairs, tasks that represent basic lower-body movements less likely to be influenced by changes in environment and social roles than are activities and instrumental activities of daily living. Results are shown for unadjusted prevalence rates and rates adjusted for changes in population composition. The findings indicate that Taiwan does not appear to be experiencing the improvements in functioning witnessed recently in the United States. Prevalence of functional limitation increased between 1993 and 1996 and between 1996 and 1999. One possible reason is the change in old-age survival, which appears to have benefited those who have functional limitations, especially in a severe form. The Universal Health Insurance programme, established in 1995, may have increased access to care and thus the survival of those in poorest health. Population Studies, 56 (2002), 265–276 Printed in Great Britain Submitted: April 2002 Final version accepted: July 2002 older Americans for the 1970s and 1980s might also have been a function of earlier diagnosis and improved access to care as a consequence of disability insurance. More recent evidence on trends in the health of older Americans has been more positive. In particular, there is a growing consensus that functional limitations (Freedman and Martin 1998, 1999, 2000) and mild disability (Manton, Corder, and Stallard 1993, 1997; Crimmins, Saito, and Reynolds, 1997; Manton and Gu 2001) have declined in the 1980s and 1990s. Interestingly, Freedman and Martin (2000) found that, even as the prevalence of many chronic diseases was increasing, the prevalence of functional limitations was declining. Possible explanations include earlier diagnosis and better disease management. Many of these studies and others are well summarized in Schoeni, Freedman, and Wallace (2001), who also note that the evidence of change in severe disability is weak. The evidence from Europe and developed countries elsewhere is even more mixed. Using French data from 1981 to 1991, Robine, Mormiche, and Sermet (1998) found, like Freedman and Martin (2000), that increases in disease were contemporaneous with declines in disability. Jacobzone, Cambois, and Robine (1999) report in an international review of evidence that there have been significant reductions in severe disability in Germany, France, and Japan, but mixed findings or no change in Australia, Canada, Netherlands, Sweden, and the United Kingdom. Waidmann and Manton’s (1998) international review uses a variety of health measures and concludes that disability is declining in Belgium, France, Italy, the Netherlands, and Switzerland, but not in Australia, Canada, and the United Kingdom. But a more recent study of Britain (Grundy et al. 1999) compares disability surveys from the late 1980s and late 1990s and finds increasing prevalence of mild disability. A recent study of the Netherlands (Portrait, Allessi and Deeg 2002) also shows increases in mild disability in the 55-to-85-year-old Dutch population between 1992 and 1998, but little change in severe disability. Of course, the studies cited above differ in many respects beyond the datasets utilized and time periods covered. There are variations in the age groups studied and in whether studies refer to current or chronic difficulties. Moreover, there are important differences in the measures of health that are used. In the United States, for instance, Freedman and Martin (1998, 1999, 2000) use ‘Nagi’ items that reflect the inability to conduct upper and lower body movements, such as lifting and climbing (Nagi 1965, 1991). Manton and colleagues and many of the others use an assortment of ‘activities of daily living’ (ADLs), such as the ability to bathe or use the toilet, and ‘instrumental activities of daily living’ (IADLs), such as ability to shop or manage money (Katz et al. 1963; Lawton and Brody 1969). An additional issue is that these ADL and IADL measures can be influenced by factors other than underlying health, such as living environment and role expectations. The study presented here assesses whether or not older adults living in Taiwan experienced improvements in functional status between the years 1993 and 1999. The focus of the study is on changes in prevalence, that is, on population-wide rates of functional limitation. The period 1993 to 1999 is an interesting one to examine because it was a time of a number of changes in Taiwan’s social and economic structure that might have influenced older adult health. The proportion elderly in the population increased substantially, but the economic growth and rapidly developing infrastructure may have provided greater opportunities for health care and better access to health-related information. In 1995 Taiwan instituted a Universal Health Insurance (UHI) programme (Taiwan Department of Health 1999) that provided, for the entire population, health insurance coverage for preventive services and most inpatient, outpatient, and in-home medical care. Although scattered social insurance programmes existed before 1995, they did not cover more than about half of the population, and the introduction of the plan resulted in a rapid and dramatic increase in utilization of both outpatient and inpatient care in Taiwan (Chiang 1997). Concurrently, Taiwan experienced an increase in life expectancy (Population Reference Bureau 1990, 2001), which no doubt was influenced by many factors both recent and past.