The risk of developing Alzheimer disease and related dementias decreased gradually with increasing scores in a dose-response manner on a model geared toward identifying healthy lifestyle factors.
A composite lifestyle score created using five factors—tobacco smoking, alcohol consumption, leisure-time physical activity (LTPA), sleep hours, and diet quality—showed that healthy lifestyles were associated with a reduced risk of Alzheimer disease and related dementias (ADRD), independent of sociodemographic factors and health conditions.1
In a population-based cohort of mostly low-income Black and White Americans, individuals had each lifestyle factor scored as either 0 (unhealthy), 1 (intermediate), or 2 (healthy) based on health guidelines, with a composite score summing all scores. At the conclusion of the analysis, those with at least 7 points of the composite score (out of 10) showed a 32% reduced risk compared to those with 0 to 3 points. Similarly, those with 5 to 6 points had a 22% reduced risk as well.
Although not necessarily a completely new finding, the study investigators, including senior author Danxia Yu, PhD, assistant professor, Vanderbilt School of Medicine, concluded that the data "support the impact of achievable, healthy lifestyles on preventing ADRD that could potentially benefit everyone to eventually reduce the health burdens and disparities posed by ADRD."
The analysis, based on the Southern Community Cohort Study (SCCS), included claims data for 1694 patients aged at least 65 years old with newly diagnosed ADRD among a cohort of 17,209 participants during a median follow-up of 4.0 years. Two-thirds of the SCCS participants were self-reported Black individuals; over half had annual household incomes less than $15,000. Cox regression models were used to estimate hazard ratios (HR) for incident ADRD, treating death as a competing risk.
After adjusting for all covariates, never smoking (HR, 0.87; 95% CI, 0.76-0.99), low-to-moderate alcohol consumption (HR, 0.81; 95% CI, 0.72-0.92), at least 150 or 75 minutes of moderate or vigorous LTPA per week, respectively (HR, 0.89; 95% CI, 0.77-1.03), getting 7 to 9 hours of sleep (HR, 0.75; 95% CI, 0.64-0.87), and the highest tertile of HEI (HR, 0.85; 95% CI, 0.75-0.96) were each associated with a 11% to 25% reduced risk of ADRD. The inverse associations between composite score and ADRD risk were even more evident when using a weighted composite score: HRs from the highest to second-lowest quartiles were 0.64 (95% CI, 0.55-0.74), 0.79 (95% CI, 0.70-0.90), and 0.88 (95% CI, 0.77-0.99) vs the lowest quartile (all P <.001).
Sociodemographic factors, obesity status, medical history, and follow-up time did not play a factor into the associations between healthy lifestyles and ADRD risk. When comparing the highest vs lowest quartiles of lifestyle scores, those with a higher socioeconomic status (SES) showed a 40%-42% lower risk of ADRD (HR, 0.58; [95% CI, 0.46-0.72] for household income ≥$15,0000/year and HR, 0.60 [95% CI, 0.50-0.72] for at least a high school graduation), while those with low SES yielded a 28%-31% lower risk (HR, 0.72 [95% CI, 0.59-0.88] and HR, 0.69 [95% CI, 0.54-0.90], respectively).
Between races, the HRs for the highest vs lowest quartiles of weighted lifestyle were similar between Black (HR, 0.69; 95% CI, 0.57-0.85) and White (HR, 0.62; 95% CI, 0.50-0.78) individuals. Additionally, there were no significant interactions based on race, income, or education (all P >.05); however, there were stronger associations observed among individuals without a history of cardiometabolic disease or depression (HRs ranged from 0.48 to 0.63). Notably, those with an existing chronic condition(s) also saw ADRD prevention benefits from healthy lifestyles (HRs ranged from 0.66 to 0.68; all P >.05).