Association of Dietary Patterns with Cognitive Function and Cognitive Decline in Sydney Memory and Ageing Study: A Longitudinal Analysis

BACKGROUND: The relationship of dietary patterns to cognitive health in older adults has attracted much research attention. However, results from existing studies are inconclusive. OBJECTIVE: The aim of this study was to investigate the association between dietary patterns and overall cognitive performance and cognitive change over time. DESIGN: This analysis was conducted as part of the longitudinal Sydney Memory and Ageing study with 6 years' follow-up. Mediterranean diet and Dietary Approaches to Stop Hypertension diet scores were generated based on dietary intake for each individual, assessed by the Dietary Questionnaire for Epidemiological Studies Version 2. PARTICIPANTS/SETTING: This longitudinal study comprised 1037 community dwelling nondemented participants aged 70 to 90 years at baseline (September 2005 to December 2007), recruited from Sydney, Australia. MAIN OUTCOME MEASURES: Neuropsychological tests assessed global cognition and 6 cognitive domains on 4 occasions, at baseline and 2, 4, and 6 years later. STATISTICAL ANALYSES PERFORMED: Linear mixed-model analyses were conducted to examine the relationship between dietary scores, food components, and overall cognitive function and cognitive change over 6 years. RESULTS: No associations of Mediterranean or Dietary Approaches to Stop Hypertension dietary scores with overall cognition and cognitive decline over 6 years were found. Higher intake of legumes and nuts was related to better overall performance in global cognition (β = .091; 95% CI: 0.035-0.146; P = .001) and to multiple cognitive domains and to less decline in global cognition (β = -.016; 95% CI: -0.032 to -0.001; P = .032). CONCLUSION: Study findings suggest that greater consumption of legumes and nuts may be important to slow cognitive decline with age.