Dementia Risk Factors Predict Individual Differences in Cognitive Function

Abstract

AbstractBackgroundTwelve modifiable risk factors have been estimated to account for 40% of dementia incidence worldwide (Livingston et al., 2020). Growing understanding of these risk factors presents the possibility that dementia risk can be partially mitigated via non‐pharmacological means, such as changes in lifestyle (e.g., alcohol consumption, social activity). We sought to provide the first systematic investigation of whether this set of risk factors also contributes to individual differences in cognitive function in a cognitively‐normal sample, and which risk factors provide the strongest contribution.MethodWe investigated cross‐sectionally the association between eight of these risk factors and cognition in 246 cognitively‐normal adults, aged 50‐90 from the Dallas Lifespan Brain Study. Risk factors included alcohol use (drinks per week), body mass index (BMI), cigarettes smoked per day, depressive symptoms (CESD scale), years of education, exercise frequency (20+ min sessions), pulse pressure, and frequency of social activity. A general measure of cognition, fluid ability, was used as the outcome variable and it was an average of six commonly used assessments of processing speed, working memory, and reasoning.ResultIn a multiple regression controlled for age and sex, 15.6% of fluid ability variance was accounted for by years of education (R 2 = .040, p = .002), frequency of social activity (R 2 = .034, p = .004), BMI (R 2 = .030, p = .008), cigarettes smoked per day (R 2 = .020, p = .032), and depressive symptoms (R 2 = .017, p = .047), as well as non‐significant contributions from alcohol use, exercise frequency, and pulse pressure. Further analysis examining cortical amyloid‐beta burden as a predictor and moderating effects of age will be discussed.ConclusionThe findings illustrate that levels of these modifiable risk factors affect cognition, even in a large sample of adults unselected for AD risk. We report differences in magnitude of effects for adults who showed cognitive decline over 10 years compared to those who were stable.