The Relationship Between Urinary Total Polyphenols and the Frailty Phenotype in a Community-Dwelling Older Population: The InCHIANTI Study

BACKGROUND: Frailty, an age-related state of increased vulnerability, is associated with a higher risk of multiple adverse events. Studies have suggested that the quality of dietary intake may affect the development of frailty. We hypothesized that frailty in older subjects would be associated with dietary total polyphenols (DTP) intake and its biomarker, urinary total polyphenols (UTP). METHODS: The Invecchiare in Chianti (InCHIANTI) Study is a prospective cohort study set in the Chianti area (Italy). We used data at baseline from 811 participants aged 65 years and older. UTP was determined using the Folin-Ciocalteu assay after solid-phase extraction. DTP was estimated using a validated Food Frequency Questionnaire and our own polyphenol database. The frailty, prefrailty, and nonfrailty states were defined according to the Fried and colleagues' criteria. Multinomial logistic regressions adjusted for potential confounders were used to assess the relationship between polyphenols and frailty. RESULTS: Both DTP and UTP concentrations progressively decrease from nonfrail to frail participants. Participants in the highest UTP tertile compared to those in the lowest tertile were significantly less likely to be both frail (odds ratio [OR] = 0.36 [0.14-0.88], p = .025) and prefrail (OR = 0.64 [0.42-0.98], p = .038). Exhaustion and slowness were the only individual frailty criteria significantly associated with UTP tertiles. No significant association was observed between frailty and DTP, after adjustment for covariates. CONCLUSIONS: High concentrations of UTP were associated with lower prevalence of frailty and prefrailty in an older community-dwelling population. A polyphenol-rich diet may protect against frailty in older persons. Our findings should be confirmed in longitudinal studies.