Abstract
BACKGROUND: Social support predicts functional and cognitive decline in aging. Yet, the associations between social support and gait speed decline-a functional vital sign-are not well understood. This study examined associations between social support and gait speed decline in aging. METHODS: Social support and gait data from 542 older adults without dementia were examined (mean age 76.1 ± 6.5 years). Baseline emotional support, tangible support, affectionate support, positive social interactions, and overall support from the Medical Outcomes Study Social Support Survey were the predictors of interest. Annual change in simple (normal pace walking) and complex (walking while reciting alternate letters of the alphabet) gait speed (cm/s) were the outcomes of interest. Linear mixed effects models examined associations between social support and gait speed decline, after adjusting for gender, race, depressive symptoms, overall cognition, and comorbidities. RESULTS: The mean annual change in gait speed was 1.8 cm/s during simple walking and 1.13 cm/s during complex walking. Tangible support was the only category of social support that predicted decline in simple and complex gait speed over a median follow-up of 3 years. The annual decline in gait speed was 0.51 cm/s (p = .008, 95% confidence intervals [CI] 0.13, 0.89) and 0.58 cm/s (p = .007, CI 0.16, 1.0) greater among those with low tangible support than in those with high tangible support during simple and complex walking, respectively. CONCLUSIONS: Tangible support is a potentially modifiable risk factor for gait speed decline. Further study is needed to examine mechanisms behind the observed associations and the potential for intervention.