Objectives: To investigate the association between total urinary polyphenols (TUPs) and total dietary polyphenols (TDPs) and cognitive decline in an older population.
Design: The Invecchiare in Chianti (InCHIANTI) study, a cohort study with 3 years of follow-up.
Setting: Tuscany, Italy.
Participants: Individuals without dementia aged 65 and older (N=652).
Measurements: TUP and TDP concentrations were analyzed at baseline using the Folin-Ciocalteu assay and a validated food frequency questionnaire, respectively. Cognition was assessed using the Mini-Mental State Examination (MMSE) and Trail-Making Test (TMT) at baseline and after 3 years of follow-up. Substantial cognitive decline was defined as a reduction in MMSE score of three or more points and an increase of at least 29 seconds on the TMT Part A (TMT-A) and 68 seconds on the TMT Part B (TMT-B) (the worst 10% of the distribution of decline) or as test discontinued because of multiple mistakes on the TMT A and B at follow-up.
Results: Higher TUP levels were associated with lower risk of substantial cognitive decline on the MMSE (odds ratio (OR) comparing extreme tertiles=0.53, 95% confidence interval (CI)=0.34-0.85, P-trend=.008) and on the TMT-A (OR=0.52, 95% CI=0.28-0.96, P-trend=.03), but not on TMT-B in a logistic regression model that adjusted for baseline cognitive score and potential confounding factors. TDP did not affect the development of substantial cognitive decline in either test.
Conclusion: High concentrations of polyphenols, a nutritional biomarker of polyphenol intake, were associated with lower risk of substantial cognitive decline in an older population studied over a 3-year period, suggesting a protective effect against cognitive impairment.
Keywords: biomarker; cognitive decline; dietary polyphenols; epidemiology; urinary polyphenols.
© 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.