Objective: To examine the association between long-term intake of total and the six classes of dietary flavonoids and decline in cognitive function over a follow-up period of up to 15 years.
Design: In this longitudinal study, we evaluated change in eight cognitive domain scores (verbal and visual memory, verbal learning, attention and concentration, abstract reasoning, language, visuoperceptual organisation and the global function) based on three neuropsychological exams and characterised the annualised change between consecutive exams. Long-term intakes of total and six flavonoid classes were assessed up to four times by a validated FFQ. Repeated-measures regression models were used to examine the longitudinal association between total and six flavonoid classes and annualised change in the eight cognitive domains.
Setting: The Framingham Heart Study (FHS), a prospective cohort study.
Participants: One thousand seven hundred and seventy-nine subjects who were free of dementia, aged ≥45 years and had attended at least two of the last three FHS Offspring cohort study exams.
Results: Over a median follow-up of 11·8 years with 1779 participants, nominally significant trends towards a slower decline in cognitive function were observed among those with higher flavanol and flavon-3-ol intakes for global function, verbal and visual memory; higher total flavonoids and flavonoid polymers for visual memory; and higher flavanols for verbal learning.
Conclusions: In spite of modest nominal trends, overall, our findings do not support a clear association between higher long-term flavonoid intake and slowing age-related cognitive decline.
Keywords: Age-related cognitive decline; Diet; Flavonoid intake; Longitudinal study; Observational study.