Where Are My Keys? Can Lifestyle Factors Predict Cognitive Function In Older Adults?

Abstract

Strong evidence shows that physical activity (PA) affects the structure of the nervous system and can improve cognitive function (CF) in older adults. Additionally, recent studies have shown that a healthy diet may protect against aging-related impairments in hippocampal structure or function. PURPOSE: To investigate the influence of PA and adherence to dietary guidelines on CF in a sample of healthy older adults. METHODS: Demographics, habitual PA (Baecke’s Questionnaire Sport score), and cognitive function (Montreal Cognitive Assessment; MoCA) were collected at consent in a sample of 359 healthy adults (50-75 years) in a memory function study. Dietary guidelines adherence (Alternate Healthy Eating Index 2010; aHEI), and two indices of cognitive function (Modified Benton Recognition Task (ModBent) and Modified Rey Auditory Verbal Learning Test (ModRey) were collected in the randomized subsample of these participants (N=211). The relationship between lifestyle factors and three outcomes (MoCA, ModBent, ModRey) were assessed using Pearson correlations in the full sample and subsample. Linear models were fit for MoCA on the full sample, and for each of the three outcomes on the randomized subsample. Each series of models included age, gender, and education. PA and aHEI scores were then added to each model and their standardized regression coefficients (change in R2) were assessed to determine whether they contributed additional predictive value towards CF. RESULTS: In the full sample, the correlation between MoCA total score and PA was weak (r = .111). In the subsample, correlations between aHEI and MoCA and between aHEI and ModRey were also weak (r = .175 and r = .141, respectively). Correlations between PA and aHEI and between age and ModRey were weak (r = .222 and r = -.219, respectively). Adding PA or aHEI did not significantly explain a greater proportion of variance in cognitive task scores beyond demographic factors alone. CONCLUSIONS: In an older adult population, there is a weak direct relationship between performance on CF tasks and lifestyle factors. Reviewing the individual standardized regression coefficients finds that education and age were the most sensitive to changes in CF task scores, and adherence to dietary guidelines was more sensitive than a measure of habitual PA.