Social Environment and Cognitive Function in an Elderly Population

David A. Landau, Georgetown University
Maxine Weinstein, Georgetown University
Shu-Hui Lin, Bureau of Health Promotion, Taiwan

This study examines the effects of the social environment – comprising socioeconomic status, social relationships, and social activities -- on cognitive function in an elderly population in Taiwan. Most previous research has found that, in general, greater richness of social ties is associated with higher cognitive performance and reduced risk of decline (Bassuk, Glass, and Berkman, 1999; Fratiglioni et al., 2000) however, Elwood et al. (1999) found social contact measures to be only weakly associated with cognitive test scores. Socioeconomic status, as measured by such factors as education and income, also shows a direct relation with cognitive performance (Long et. al., 2001; Elwood et al., 1999; Ofstedal, Zimmer, and Lin, 1999; Inouye et al., 1993), although a few studies reflect little or no relationship between these variables (Black et al.,1999; Marquis et al., 2002). Several studies have examined the relationship between socio-demographic characteristics and cognitive impairment (Marquiset al., 2002; Blacket al., 1999), while other studies have focused on social activities and contacts and their relation to cognition (Elwoodet al., 1999); however, few studies (Bassuk, Glass, and Berkman, 1999; Fratiglioni et al., 2000) have simultaneously controlled for both socio-demographic characteristics and social activities and networks. Even fewer studies have combined these factors with controls for health behaviors such as drinking and smoking, and functional status and other measures of physical health (but see Ho et al., 2001). Our study provides an opportunity to account for the joint effects of the social environment, demographic characteristics, and health on cognitive function. We use a longitudinal, population-based study of the elderly in Taiwan to examine the relationship. The first survey, initiated in 1989 (N=4049), was a nationally representative probability sample of males and females aged 60 and over; follow-up surveys were conducted in 1993, 1996, 1999, and 2000. The data for the present study comprise answers to the questionnaires in the 1993, 1996, 1999, and 2000 waves, although variables regarding education are drawn from the 1989 survey as a baseline characteristic for our study. We use Poisson regression models that incorporate random effects for individual respondents applied to two separate subsets of survey data to explain variation in cognitive function. The first application will use cognitive data from 1993, 1996, 1999 and social data from 1993 and 1996. We will examine cognitive function for each respondent in 1999 and 1996 as a function of cognitive, social, and health data from the respective previous study. The second application is similarly structured but utilizes cognitive data from 1996, 1999, and 2000 and controls from the 1996 and 1999 surveys. We use this approach in order to maximize the contribution of questions (some of which changed over time) from each study. In each case we use a block hierarchical design, first introducing factors related to social relationships and activities, then assessing the effects of demographic and health-related factors. Our measures of cognitive function for the first model use five questions that address basic orientation (three questions); long-term memory (one question); and the respondent’s ability to perform calculations (one question). The second model includes two additional tests of recall. Our measures of social relationships include marital status, familial composition, living arrangements, social network (contact with family/friends), familial support, and leisure activities. Education and current financial status, including measures of income and a financial satisfaction index, are used to determine socio-economic status. Our health factors include a self-evaluation of health, tobacco use, alcohol consumption, depression, and functional status. Our initial assessments of cognitive function based on the questions available in the study show that between 1993 and 1999, approximately 15 percent of the (surviving) respondents had declines in orientation; 2 percent had a reduction in long-term memory; and 16 percent had reduced calculation capacity and for the period between 1996 and 2000, just over 18 percent showed increased deficits in recall. These declines are consistent with several studies examining longitudinal cognitive performance (Brayne et al., 1999; Christensen et al., 1994). Participation in social activities and maintenance of social networks provide potentially important points of intervention for policy-makers. 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Presented in Poster Session 4: Aging, Population Trends and Methods, Religion and Gender