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Zachary Zimmer, Mira Hidajat, and Yasuhiko Saito

1 Introduction

1.1 Demographic Change in China and Implications for Disability
This study looks at whether and how total and disability-free life expectancy among older
Chinese has been changing, whether the changes suggest a compression of morbidity, and
whether changes are consistent across sex, education and rural/urban residence. The topic
is important given demographic changes experienced by China over the last few decades.
These changes are influencing China’s age structure. According to estimates from the
United Nations (2013), around 1970 the Total Fertility Rate and Crude Birth Rate meas-
ured about 6 children per woman and 40 births per 1,000 persons respectively; rates typi-
cal for developing countries. Nonetheless, by about 2000, these figures dropped steeply to
about 1.5 and 14 respectively; rates typical of more developed countries. While total mor-
tality also declined, it is mortality among older persons that is consequential for the current
study. World Health Organization (2012) estimates indicate life expectancy at 65 was 13.2
for males and 14.5 for females in 1990 and rose to 14.3 for males and 16.4 for females by
2009. Over the same period, the percent chance that a 65 year old survived to 80 increased
from about 40% to 47% for males and 48% to 58% for females.
As demographers have long recognized (Goldstein, 2009), precipitous declines in fertil-
ity leads to population aging. Thus, China’s population is now among the fastest aging
population in the world (Chen and Liu, 2009). Ever increasing longevity is resulting in
aging amongst the aged since those reaching old age are surviving to more advanced ages.
Data from the United Nations (2013) reveals the fastest growing portion of China’s popu-
lation today is its oldest-old. Those 80+ are growing at more than 5% per year, which re-
sults in a doubling of the oldest-old population in less than 14 years, while growth rates for
other ages remain stable or are negative.
These changes have implications for population-wide prevalence of health problems
that tend to increase with age (Kinsella and Phillips, 2005). Disability, defined as the in-
capacity to accomplish tasks on one’s own, that are necessary for daily survival like feed-
ing and bathing (Verbrugge and Jette, 1994), is one of these problems. Still, the precise
impact of demographic changes on disability depends on a number of factors. One is how
disability rates change as survival increases. There are several scenarios, each of which has
implications. One scenario assumes a status quo whereby there are few changes in the
tendency to have disability at different ages. An alternate scenario is one where as people
live to increasingly advanced ages they are living additional years in good health and thus
age-specific disability rates are falling. This is consistent with the notion of a compression
of morbidity, initially popularized by James Fries (1980), which predicts that as longevity
expands morbid conditions become increasingly compressed only into a short time pre-
ceding death. Although a compression of morbidity technically concerns what is happen-
ing just before death, if it is occurring then we would expect people to be living both long-
er lives and a greater proportion of life in a healthy state. A third possible scenario
represents a compromise which we term as heterogeneous compression, whereby a com-
pression of morbidity occurs among certain subgroups. For instance, the compression may
be occurring for more advantaged populations like those with higher education or living in
areas where there is uncomplicated access to health care.
Clearly, for a country like China, which of these is taking place has implications for
population health. With a scenario resembling a status quo, a greater number of older per-
sons mean more disabled. With a scenario resembling a compression of morbidity, popula-
tion aging and increasing longevity does not necessarily mean more disability. A hetero-
geneous compression is suggestive of inequalities in health and aging and might point to-
wards a situation whereby some groups are advantaged more so than others.

International Journal of Population Studies | 2015, Volume 1, Issue 1 5