Background: Among community dwelling older adults, social vulnerability increases with age. Advanced age alone does not fully explain how or why older adults become more socially vulnerable; frailty may offer a better explanation.

Objective: We aimed to understand how change in frailty relates to change in social vulnerability over time.

Design: Retrospective cohort study.

Setting and Participants: We analyzed older adults aged 65 years and older from the province of Nova Scotia who accessed publicly funded home care in 2005 and 2008 followed for up to ten years.

Measurements: We measured social vulnerability and frailty using indices. Controlling for time constant covariates, multi-level growth modelling was used to evaluate whether within-person changes in frailty were associated with within person changes in social vulnerability, after accounting for between-person differences.

Results: There were 2,791 older adults in the 2005 cohort and 2,741 older adults in the 2008 cohort. Mean age, frailty index and social vulnerability index were 80.6 years (SD 7.5), 0.23 (SD 0.10), 0.22 (SD 0.07) and 80.4 (SD 7.6), 0.23 (SD 0.10), and 0.23 (SD 0.07) for each cohort respectively. After accounting for age, sex and baseline frailty, a 0.1 point increase in change of FI from baseline was associated with a 0.017 (CI 0.016 – 0.019, p<0.001) increase in SVI in the 2005 cohort and a 0.014 (CI 0.013 – 0.016, p<0.001) increase in SVI in the 2008 cohort.

Conclusions: Although social vulnerability tends to remain constant in the absence of increases in frailty, changes in frailty are closely associated with changes in social vulnerability. Incorporating within-person changes in health into quantitative models of late-life social may further improve our understanding of how and why some individuals are able to stay in the community despite their vulnerabilities.