The Disablement Process among Elderly Chinese

The purpose of this study is to determine whether the Disablement Process (DP) model is supported by data from a large survey of elderly Chinese ages 65-105 years old (the Chinese Longitudinal Healthy Longevity Survey). It is expected that, as described by the DP model and earlier models, functional limitations will mediate the relationship between impairments and disability (measured via activities of daily living). The main point of interest is whether an intraindividual factor (a subjective sense of social isolation, or loneliness) and an extra-individual factor (adequate medical care) moderate the disablement process among this sample of elderly Chinese. Findings (a) support prior research showing the relative importance of lower(versus upper-) body functional limitations for ADL disability, (b) suggest the indirect importance of both adequate medical care and of reported loneliness for levels of ADL disability, and (c) demonstrate that hypertension has direct effect, in addition to indirect effects, on levels of ADL disability. Future in-depth investigation of factors that mitigate and exacerbate later-life disablement in Chinese contexts is necessary and important. The Disablement Process among Elderly Chinese 3 INTRODUCTION Research on the disablement process among Chinese elderly is important for two reasons. First, China is home to a rapidly aging population of elders that surpasses 100 million in number (Feng and Xiao 2007). Clearer understanding of later-life disablement processes in this society would contribute to the effectiveness of interventions designed to reduce current and future rates (and levels) of disability. Secondly, the disablement process has been studied mostly in the context of Western developed nations. To the extent that we understand disability as, at least partly, a social condition – that is, as the difference between environmental demand and individual ability -and that we view disablement as a social process, it makes sense to suspect that pathways of disablement may differ across social contexts. On the other hand, it may be that a single model of the disablement process applies across social settings, and that only prevalence rates or the particular factors that promote or hinder disability vary. Findings from research on disablement processes in a Chinese context are therefore theoretically, as well as practically, significant. Following similar studies conducted on data from the United States and other developed nations, (Peek et al. 2005; Lawrence and Jette 1996), this paper asks whether the Disablement Process (DP) model is supported in data from a study of elderly Chinese ages 65-105 years old. It is expected that, as described by the DP and earlier models, functional limitations will mediate the relationship between impairments and disability. The main point of interest is whether, as the DP model would suggest, intra-individual and extra-individual factors moderate disability among this sample of elderly Chinese. The paper begins with a brief review of the conceptual model, existing research, and a description of the Chinese context. A discussion of the results and of the observed associations between risk factors, functional limitations, and intra-/extra-individual factors concludes the paper. The Disablement Process Model and its Components The Disablement Process model (Verbrugge and Jette 1994) (DP) posits that disease and impairments lead to functional limitations which in turn result in disability (see Figure 1). Functional limitations are here defined as restrictions in physical or mental actions; for example, walking, standing, bending, or grasping items. Disability is defined as the gap between expectations and ability to fulfill those expectations; that is, as difficulty acting “in necessary, usual, expected and personally desired ways in [one’s] society” (Verbrugge and Jette 1994). In other words, a functional limitation need not be a disability unless the environment requires the ability to complete that particular physical or mental action. Defining disability in this manner allows us to understand disability as a sociological, not only a physiological, condition. The DP model adds to prior conceptualization of disablement (Nagi 1976) by arguing that intraindividual factors (e.g., psychosocial attributes and behaviors) and external conditions The Disablement Process among Elderly Chinese 4 (medications and technologies, and built environment) can promote or deter disablement and the speed of the process (see Figure 1). Although the argument is appealing, more empirical research is needed to lend support to this key proposition. Should the moderating role of intra-individual and extra-individual factors be solidly demonstrated by research, it will be important to theorize whether and how these factors differ across socio-cultural and political contexts. Lawrence and Jette’s (1996) study was the first to empirically test the DP Model. Using three waves of the Longitudinal Study of Aging (LSOA) they found that lower-extremity functional limitations, more so than upper-extremity functional limitations, were significantly and directly related to IADL disability. Results from this research suggest that lifestyle does not directly affect disability, but rather, that behaviors such as lack of physical activity affect disability through their influence on functional limitations. Other studies in Western developed societies have lent general support for the DP model but also raise additional questions and points for future investigation. They suggest that future research examine not only the influence of intraand extraindividual factors along the disablement pathway, but also the relative importance of lowervs. upper-body limitations, the potential direct effects of pathologies/impairments on disability, and the possibility that diseasespecific variations might exist in the disablement pathway. Femia et al (2001)’s Swedish study found support for a strong link between lower body functional limitations and disability, and also for the significant role of intraand extra-individual factors (depression and social integration) on the severity of disability. Peek et al. (2005) examined the process of disablement among a sample of older Mexican-Americans and found that only (lower body) functional limitations, but not socio-demographic characteristics or the intra-individual factor of emotional support had direct effects on ADL disability. One pathology, diabetes, was found to have a direct (as well as direct) effect on disability. Other researchers have proposed detailed and comprehensive models of disablement specific to rheumatoid arthritis (Escalante and Rincon 2002) and dementia (Barberger-Gateau 2004) which may or may not be applicable to other chronic illnesses. Another area in need of exploration is the potential for ethnic/racial variation in the pathway from disease to disability. Results from research by Zsembik et al. (2000) suggest that the DP model may better explain disability for some racial/ethnic groups than for others, and that the periods most crucial in the disablement process may vary by socio-cultural groups as well. Perhaps just as likely are socio-cultural (that is, interas well as intra-national) differences in the extent to which the DP model adequately describes the process(es) of disablement. Socio-cultural environments may not only shape expectations (environmental demands) of and for later-life experience (Levy and Langer 1994) but also actual physical abilities. This study contributes to research on later-life disability by examining the applicability of the DP model among a sample of elderly people in China. The Disablement Process among Elderly Chinese 5 Disablement and Chinese Elderly China’s population is rapidly aging and is projected to be one of the world’s oldest populations by 2050 (Poston & Zeng 2008). Improvement in Chinese population health during the last century raised life expectancy and sharply decreased mortality rates (Banister 2004). As in other settings, a growing number of elderly people is expected to increase rates of impairments and disability ((Moran, Lv, & Chen 2008; Wang et al. 2005). After adjusting for sociodemographic factors, oldest-old Chinese report less general ADL disability than do the US oldest-old, although the very oldest Chinese (90 years and older) have difficulty with eating and toileting to a greater extent than do American elders of the same age group (Moran, Lv, and Chen 2008). However, this higher rate of difficulty is likely due to differences in physical conditions and cultural practices (i.e., floor toilets and the standard use of chopsticks). Using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), Zeng et al. (2002) show that on the whole, ability to perform activities of daily living (ADL) begins to decline rapidly around age 80, and particularly after age 85. Women report more difficulty in performing ADL tasks compared to men, and the urban elderly are disadvantaged in terms of ADL performance. Because living conditions, socio-economic status, and health care is generally poorer in China’s rural areas compared to urban centers, it may come as a surprise that rural elders report higher ADL scores. However, a rural advantage can be at least partly explained by Clarke and George’s (2005) finding that particular characteristics of built environment, namely greater land-use diversity, act as a deterrent to disability in later-life. It is likely that Chinese rural elders have relatively more opportunities to walk and perform outdoor leisureand farming activities, as well as greater likelihoods of having engaged in physical labor over their life course, than do their urban peers. Zimmer and Kwong (2004), using measures of self-care and chronic disease, also find that urban elders report more functional limitations than do rural counterparts. Still, there is some conflicting