A Study onDETERMINANTS OF HEALTHY

LONGEVITY IN CHINA

A. Introduction of Chinese longitudinal survey on Healthy Longevity;

B. Some Results of the Data Analysis

Zeng Yi

A. A BRIEF INTRODUCTION to Chinese Longitudinal Survey on Healthy Longevity

• This is a Duke-PKU collaborative large project, aiming at

•To better understand determinants of healthy longevity, such as social, economical, behavioral, environmental and biological factors.

•To provide data information for academic research, health and aging policy analysis.

Progress of longitudinal surveys in 1998, 2000, and 2002

(1) Achieved sample size distributions.

-- Extensive questionnaire data were gathered from 8,959, 11,161, and 11,163 oldest-old aged 80+ in 1998, 2000, and 2002, respectively.

-- Among them, 8,170, 10,457, and 12,656 interviews were conducted with centenarians, nonagenarians, and octogenarians, respectively;

-- Data on date/cause of death, health status, socioeconomic status, and degree/length of disability and suffering before dying, etc., were collected from 2,783, 2,406 and 1,449 deceased interviewees aged 100+, 90-99, and 80-89, respectively.

(2) Significant Extension of CLHLS study since 2002

-- Thanks to NIA, UNFPA, China Social Science Foundation, Peking University, Taiwan Academia Sinica and Mainland China Academy of Social Science, we added 4,894 younger elderly aged 65-79 and 4,478 elderly interviewees’ adult children aged 35-65 into our sample in 2002 wave.

-- The total sample size is now over 20,000 interviewees including oldest-old (focus), younger elderly (as a comparison group) and elders’ adult children (intergenerational relations and healthy longevity).

Sample Distribution, 1998-2002

 

Age

Survival interviewees deceased (proxy interview)follow-up newly interview Total

M F T M F T M F T M F T

1998 baseline survey80-89 NA NA NA 1787 1741 3528 1787 1741 3528 NA NA NA90-99 NA NA NA 1299 1714 3013 1299 1714 3013 NA NA NA100+ NA NA NA 481 1937 2418 481 1937 2418 NA NA NATotal NA NA NA 3567 5392 8959 3567 5392 8959 NA NA NA2000 follow-up survey80-89 996 1048 2044 1471 1403 2874 2467 2451 4918 339 262 60190-99 720 907 1627 925 1260 2185 1645 2167 3812 574 612 1186100+ 262 891 1153 256 1022 1278 518 1913 2431 348 1213 1561Total 1978 2846 4824 2652 3685 6337 4630 6531 11161 1261 2087 33482002 follow-up survey35-65 NA NA NA 3132 1346 4478 3132 1346 4478 NA NA NA65-79 NA NA NA 2456 2438 4894 2456 2438 4894 NA NA NA80-89 1454 1411 2865 673 672 1345 2127 2083 4210 483 377 86090-99 948 1236 2184 590 858 1448 1538 2094 3632 547 679 1226100+ 277 917 1194 442 1685 2127 719 2602 3321 295 941 1236Total 2679 3564 6243 7293 6999 14292 9972 10563 20535 1325 1997 3322

NA -- Not applicable

(3) Sampling areas

-- The survey was conducted in the randomly selected half of the counties and cities of 22 provinces out of the total of 31 provinces where Han are majority.

 

-- The population in the survey areas constitutes about 85 percent of the total population in China.

PERSPECTIVE

1. General plan of our 2005 and 2008 follow-up surveys

2. Further in-depth data analysis to better understand the determinants of healthy longevity

Data Availability:The 1998 baseline and 2000 follow-up healthy longevity survey data is now being dis

tributed internationally by the Peking University Center for Healthy Aging and Family Studies (http://www.pku.edu.cn/academic/population/center/index.htm) and the program project at Duke University (http://www.pubpol.duke.edu/centers/ppa/). The data processing and preliminary analysis of the 2002 follow-up survey are underway and the data sets of 2002 wave will be distributed internationally in October 2004.

Contacts:Prof. Liu Yuzhi, Peking University; E-mail: chafs@pku.edu.cn or yuzhil@pku.edu.cnDr. Danan Gu, Duke University;E-mail: danan@aas.duke.edu

B. Some Results of the Data Analysis

(a) CORRECTING THE UNDERESTIMATION OF DISABLED LIFE EXPECTANCY:

The CLHLS new data collection has led to a New Method & Application to the Oldest Old In China (Zeng, Gu, and Land, 2004)

Previous research has indicated that the underestimation of disability is one of the major problems in research on population aging (Gill et al. 2002; Guralnik and Ferrucci 2002)

We found that extant studies of active/disabled life expectancy based on multi-state life table implicitly assume that persons who die between ages x and x+1 (or ages x and x+n) do not change their functional status between age x and time of death.

Such unreasonable assumption has resulted in that the widely used disabled life expectancies based on conventional methods are significantly underestimated.

Based on the unique CLHLS data on ADL before dying, we propose a new method to correct the underestimation of disabled life expectancy inherent in the MSLT method.

Results and Discussion

1. Underestimation of disabled life expectancy by classic MSLT method

①    Proportion of underestimated disabled life expectancy by conventional MSLT method at age 80 are 10% and 6% for males and females respectively. With advancing of age, such underestimation declines ----the underestimation of disabled life expectancy is statistical significant.

②    The underestimation of disabled life expectancy is larger for males than for females.

③ The underestimation of disabled life expectancy is around 12% and 6% for males and females at age 65 respectively based on the extrapolation.

Fi g 1. % of underest i mated di sabl ed l i f e expectancy (DLE) by convent i onal MSLT approach

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80 85 90 95 100

Age

%

Male

Female

Gill et al. (2002) demonstrated that prevalence rates of disability at different waves with longer intervals between waves (e.g. 1-5 years) are substantially underestimated.

Gill and colleagues proposed to substantially reduce the length of the observation intervals between interviews or using monthly telephone interviews---- but largely increase the costs.

Age and gender differentials in status-based ALE after correcting the underestimation of disabled life expectancy

Figure 4. Percent of Remaining Life Spent in Active Status

among Chinese Oldest Old Males and Females

Who Are Active or Disable at Initail Age y

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40

60

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80 85 90 95 100

Initial Age y

% Male

Female

Male

Female

ADL Active at

Initial Age y

ADL Disabled

at Initial Age y

Life table proportions of the extent of morbidity before dying among the oldest old who are active or disabled at initial ages

The slight morbidity profile: refers to those who were ADL active & bedridden for <5 days (including not bedridden).

•The moderate morbidity profile: refers to those who were ADL active &

bedridden for ≥5 days or ADL disabled & bedridden for <5 days.

•Severe morbidity profile: refers to those who were ADL disabled &

bedridden for 5-59 days.

•The long-term severe morbidity profile: refers to those who were ADL

disabled & bedridden for ≥60 days.

（ 1 ） ADL disability at Survey is strongly associated with the extent of morbidity before dying.

（ 2 ） As compared to their male counterparts, Chinese oldest old women not only survive in a more likely disabled status, but also suffer more before dying

（ 3 ） Our empirical results show that the life table proportions of slight morbidity death over initial age y generally do not decline with the increase of age y

----This is generally consistent with previous similar studies and provides additional evidence concerning debates on the hypothesis about compression of morbidity (Fries 1980), or Morbidity dynamic equilibrium (Manton 1982).

---- reject the hypothesis of a pandemic of disability (Gruenberg 1977)

---- healthy longevity (i.e., achieving longevity while relatively compressing morbidity) is not impossible (Hubert et al. 2002)

(b) Positive Life Satisfaction & Healthy LongevityAge differentials of physical performance, activity of daily living, good cognitive function, self-reported good health and life satisfaction of the oldest old

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80-84 85-89 90-94 95-99 100-105

%

健康自评好 self reporting good health

生活满意度自评好self-reporting satisfaction

认知功能好MMSE: good cognitive function

生活能自理ADL active

能原地转圈turn around 360 degree

整体健康好well-being

We find that life value in terms of positive personality, optimistic attitudes and positive view of current life has beneficial effects on health and longevity. Such positive value should be advocated.

Our unique data from the oldest-old aged 80-105 with largest survey sample size ever conducted have shown that life satisfaction and happiness is one of the secrets of healthy longevity.

Thank you !