Social Vulnerability Predicts Frailty: Towards a Distinction between Fragility and Frailty?

BACKGROUND: All definitions of frailty converge in two aspects: the notion of loss or decline and the ability to predict negative health outcomes. Numerous factors were reported to be associated with frailty among which biological, psychological, economic and social factors. Whether the latter contribute at the same level is a relevant question, as social vulnerability does not refer to an ongoing process of decline leading a person to become frail but rather to a relativity stable state making the person fragile. Thus, social vulnerability should increase the risk of frailty. OBJECTIVES: This study aims at assessing whether social vulnerability increases the risk of incident frailty. METHODS: 1531 participants aged 65 or older from the PAQUID cohort study were included. Cox regression models tested the association between social vulnerability index (SVI, based on 28 social items) and frailty index (FI, based on 25 health-related items) over the 27 years of follow-up. RESULTS: Adjusted for age and sex, higher SVI was associated with increased risk of incident frailty (HR=3.85, 95% CI=1.87-7.94, p<.001). After additional control for IADL disability and comorbidities, higher SVI was associated with increased risk of frailty (HR=3.40, 95% CI=1.63-7.07, p<.05). The association remained significant after controlling for MMSE (HR=2.34, 95% CI=1.08-5.07, p<.05). DISCUSSION: Poor social status is a risk factor of frailty. From a conceptual point of view, our results claim for a distinction between the concepts of frailty and fragility, the first one being the consequence of an ongoing decline, the other one related to a relatively stable condition of fragility, mainly explained by unfavorable social conditions.