Depression has been known to be associated with functional limitations in elderly populations and screening is an effective preventive approach. The purpose of this study was to examine the contribution of depression in explaining the functional status of community-dwelling older adults and to explore the utility of a short version 5-item Geriatric Depression Scale (GDS-5) as a screening tool.
Design: Cross-sectional survey Settings: Six hospitals and communities served by home-delivery meal programs Participants: 529 individuals aged 60 years and older.
Measurements: Using structured survey questionnaires, key variables including demographics, depression status, and two domains of functional status assessed by basic Activities of Daily Living (ADL) /Instrumental ADL (IADL) and mini-mental status (MMSE) were collected. To determine the unique contribution of depression in explaining functional status of participating older adults, hierarchical multiple regression was conducted.
Results: The model explained 18 % of the total variance in physical function and 21 % of the total variance in cognitive function. Race/ethnicity and depression were significant predictors of functional status. In particular, entry of the depression variable resulted in a significant R square change of 7%, accounting for a unique portion of the ADL/IADL variance. In terms of cognitive function measured by MMSE, entry of the depression variable showed a small, but significant change. Older adults who were ethnic minorities and had depression were significantly more likely to report poor perceived physical and cognitive function. Hierarchical multiple regressions revealed that some personal factors such as age, education, race/ethnicity contributed to the explanatory model, and depressive symptoms significantly explained additional variance. GDS-5 was less reliable (Cronbach's alpha= 0.5) to assess depressive symptoms in this study.
Conclusion: Depression was a significant contributing factor to functional limitations of older adults. A short 5-item version of the GDS could be used to screen older adults, but two-tiered GDS-5/15 would be better alternative tool.