Lifestyle Factors Related to Cognitive Aging

Cognitive changes are a hallmark feature of Alzheimer's disease (AD) and lifestyle behaviors have been associated with a reduced risk of disease onset and slower rate of cognitive decline. Research examining the relationship of lifestyle factors (LFs) to brain health has typically focused on individual factors in isolation (more physical activity (PA) and reduced risk of AD); however, few studies have examined the combined effects of multiple LFs on cognition. The current study aimed to 1) determine which LFs best predict cognition cross-sectionally; 2) derive and compare different approaches to developing a Health Score (HS) to help predict cognition; and 3) discern if a healthy lifestyle was associated with slower rate of cognitive decline. This study included 467 older adults (Mage=83; No Cognitive Impairment=361, Mild Cognitive Impairment (MCI=94), Alzheimer's dementia (AD=12)) enrolled in a longitudinal (Myears=3.72) aging study with yearly evaluations, including neuropsychological testing, clinical evaluation, and detailed assessment of lifestyle behaviors: diet, PA, sleep, social activities, stress, depression, alcohol, smoking, body mass index (BMI), and APOE genotyping. Cognitive z-scores were derived for global cognition, verbal memory, processing speed, and working memory. HS based on a Scientific (i.e., data driven), Lifestyle/Health (i.e., only healthy lifestyle behaviors), Risk/Disease (i.e., only unhealthy behaviors), or Comprehensive (i.e., all healthy/unhealthy behaviors) approaches were calculated and categorized (Unfavorable, Minimally Favorable, Moderately Favorable, Favorable) based on quartiles. Rate of cognitive change was also calculated. Multiple linear regression analyses in the full sample revealed demographic and lifestyle (i.e., social activities, diet) factors consistently predicted cognition cross-sectionally. In the MCI/AD group, diet, PA and BMI were significant predictors with minimal demographic predictors. HS comparisons via Meng's test revealed a Lifestyle/Health approach as the best predictor of cognition compared to the other approaches. In addition, individuals with HSs in the Favorable category had significantly slower rates of cognitive decline than individuals in other categories. Overall, LFs better predicted cognition than risk factors commonly used in clinical and research settings. Results from this study corroborate prior findings and encourage continued support and resources for lifestyle research and intervention programs to help prevent and slow cognitive decline and AD.