Friday, 14 January 2005 - 12:00 PM

This presentation is part of: Poster Session I

The Disabling Effect of Late-Life Depression: How Much Does Depression Contribute to Functional Deterioration Among Older Adults?

Purpose: The purpose of this study was to examine the extent of the effect of depression on the changes in older adults’ functional health over a 2-year period. Although many previous studies found a significant reciprocal relationship between late-life depression and functional impairments, the magnitude of the influence of depression on longitudinal changes in functional health has not been examined (Bruce, 2001). Methods: The data were drawn from the 1998 and 2000 interview waves of the Health and Retirement Study, and the study sample consisted of 6,415 persons aged 65 years or older reporting no impairment in their activities of daily living (ADL) and instrumental activities of daily living (IADL) in 1998. At follow-up 2 years later, 13.2% of the sample reported that they had one or more ADL/IADL impairments. Depressive symptoms were measured with the short form Center for Epidemiologic Studies Depression Scale (CES-D), and 17.2% of the sample members were identified as depressed at the time of the baseline interview. Analysis was done using gender-separate stepwise linear regressions with the number of ADL/IADL impairments at follow up as the dependent variable and the following four blocks of variables as covariates: (1) Demographic and social integration variables: Age, race/ethnicity (Non-Hispanic white, African American, and Hispanic), marital and spousal caregiving status, number of children, years of education, family income, and work and volunteering status; (2) baseline health status and changes in health status between baseline and follow up: The number of existing chronic illnesses diagnosed by a doctor at baseline, the numbers of newly diagnosed illnesses and hospital stays between baseline and follow up, and baseline self-rated health; (3) baseline CES-D score and the CES-D score squared (to capture the possible curvilinear impact of depressive symptoms); and (4) indicators of health-related behaviors between baseline and follow up: Engagement in a vigorous exercise routine, smoking status, and the average number of weekly drinking days. By controlling for sociodemographic and health variables in the stepwise regression, the net effect of baseline depressive symptoms on functional health change was estimated. Results: For both genders, demographic and social integration variables, especially age, marital and caregiving status, number of children, years of education, and work and volunteering status, explained 4-5% of the variance in the 2-year change in functional health. The baseline health status, newly diagnosed illnesses, and hospital stays added 3% (male) to 6% (female) to the explained variance. The baseline CES-D score and the squared CES-D score added less than 1% to the explained variance for both genders. In the last block of the covariates, continuing exercise alone added 0.010 to the R-square. Implications: Although baseline depressive symptoms were a significant contributor to functional deterioration, their net disabling effect appeared to be very limited. The practice implications are that, aside from pharmacological and talk therapy interventions that have been proven effective in treating late-life depression, simple intervention programs geared to increasing older persons’ social integration and facilitating regular exercise routines can easily offset the negative disabling effect of depressive symptoms.

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