The aim of this proposal is to test the hypothesis that psychosocial factors contribute to physical and social functioning in elderly adults. Although most disability models postulate that underlying physical capacity drives physical functioning which in turn drives social functioning, community based data clearly indicate that these relationships show less than a one-to-one correspondence, leaving considerable unexplained variance in functioning. This proposal requests 2 years funding to conduct secondary data analyses to address a fundamental question in aging research: Why is it that some people function better than would be expected given their capacity while others function more poorly than would be expected? In this proposal, we test the hypothesis that psychosocial factors, specifically depression, social ties, and emotional support, explain some of the otherwise unexplained variance in physical and social functioning in elderly, community-dwelling adults. Specifically, the study hypothesizes that among elderly, noninstitutionalized adults: l) Depression levels and social ties/support each have a direct effect on physical functioning, net of physical capacity, sociodemographic factors, and medical conditions; 1a)The effect of depression and social ties/support on physical functioning will be greatest among individuals with the highest levels of physical capacity; 1b) Disadvantaged subgroups of the population, as defined by sociodemographic characteristics, are more vulnerable to the effects of depression and social ties/support on physical functioning; 2) Depression levels and social ties/support each have a direct effect on social functioning, net of physical functioning, sociodemographic factors, and medical conditions; 2a)The effect of depression and social ties/support on social functioning will be greatest among individuals with highest levels of physical functioning, 2b) Disadvantaged subgroups of the population, as defined by sociodemographic characteristics, are more vulnerable to the effects of depression and social ties/support on social functioning, and 3)The effects of depression and social ties/support on functioning persist after taking into account the reciprocal effects of functioning on depression and social ties/support. These hypotheses will be tested using 3 existing longitudinal community-based data sets. Although these data sets share many characteristics in terms of sampling and measures, their differences in terms of time periods between interviews, average level of functioning, and conceptualization of depression allow the proposed analyses to test the robustness of findings under varied sampling and measurement conditions. The analytic strategy has two parts: l) risk factor analysis, and 2) structural equation analysis to test hypothesized models of the causal relationships among variables. By examining factors which contribute to both physical and social functioning in the same set of analyses, this application proposes a more complete examination of the disabling process than currently available in the literature. Because both depression and disadvantaged social ties/supports are problems found in elderly populations and are potentially modifiable, identification of their contribution to physical and social functional levels becomes an important strategy for intervening into declining functioning and negative sequelae such as dependence and mortality.
