Summary: Adopting healthier habits or making modest lifestyle changes can lower the risk of developing Alzheimer’s disease and related dementias, particularly for people from lower socioeconomic backgrounds.
Source: American Society for Nutrition
As rates of Alzheimer’s disease and other dementias rise in the U.S., new research highlights that everyday lifestyle factors—diet, physical activity and sleep—can play a significant role in reducing dementia risk.
Two recent observational studies provide insights into why non-White and low-income populations often shoulder a disproportionate share of dementia cases, and how modifiable behaviors may help reduce that burden.
“Our results support the protective role of healthy lifestyles in preventing Alzheimer’s disease and related dementias among older Americans, including those facing socioeconomic disadvantages,” said Danxia Yu, Ph.D., assistant professor in the Division of Epidemiology at Vanderbilt University Medical Center and lead author of the studies.
Yu emphasized the practical barriers many people encounter: “It can be difficult for individuals dealing with systemic and structural disadvantages to adopt and maintain healthy behaviors. Public health strategies should focus on making lifestyle changes feasible and accessible for all, especially disadvantaged communities.”
The findings were presented at Nutrition 2022 Live Online, the American Society for Nutrition’s annual meeting (June 14–16), and were published June 13, 2022, in Neurology.
Both studies used data from the Southern Community Cohort Study, a long-term research effort begun in 2001 to investigate disease causes and health disparities. About 85,000 participants were recruited from community health centers across the southeastern U.S.; roughly two-thirds are Black, making this one of the most representative U.S. cohorts of African-American participants. Researchers tracked Alzheimer’s diagnoses using Medicare claims among participants aged 65 and older.
In the first study, researchers analyzed 17,209 older participants, 1,694 of whom were diagnosed with Alzheimer’s or related dementias over a median follow-up of four years. They evaluated five lifestyle factors—smoking, alcohol use, leisure-time physical activity, sleep duration and overall diet quality—both individually and combined into a composite score.
Individually, healthier behaviors were associated with an 11–25% lower risk of Alzheimer’s and related dementias: never smoking, meeting recommended physical activity levels, consuming low-to-moderate alcohol, obtaining adequate sleep, and eating a higher-quality diet all showed protective associations. When combined, the five-factor lifestyle score showed a dose-response relationship: participants in the highest quartile of healthy behaviors had a 36% lower risk compared with those in the lowest quartile. These associations persisted after adjusting for age, sex, race, education, income and chronic health conditions.
The second study included 14,500 older participants, with 1,402 developing Alzheimer’s or related dementias. Investigators assessed intake of dietary polyphenols—plant compounds found in tea, berries, chocolate and red wine—grouped into flavonoids, phenolic acids, stilbenes and lignans, using a validated food-frequency questionnaire and polyphenol databases.
Researchers observed notable racial differences in polyphenol consumption: White participants reported approximately double the daily intake of total polyphenols compared with Black participants. Overall, total polyphenol intake was not significantly associated with dementia incidence in either racial group. However, some subclasses of flavonoids were linked with reduced risk among Black participants but not White participants. For example, Black participants in the highest quartile of tea consumption had a 28% lower incidence of Alzheimer’s disease than those in the lowest quartile.
Both studies are observational and do not establish causal mechanisms. Nevertheless, the authors suggest plausible pathways by which healthy lifestyles may protect brain health—improving glucose and lipid metabolism, reducing systemic inflammation and lowering psychological stress.
Yu called for more research focused on diverse and socioeconomically disadvantaged populations: “Black Americans and people with low socioeconomic status face higher rates of Alzheimer’s disease but have been underrepresented in epidemiologic research. Identifying modifiable prevention factors across different racial and income groups is a critical public health priority.”
About this Alzheimer’s disease research news
Author: Press Office
Source: American Society for Nutrition
Contact: Press Office – American Society for Nutrition
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Original Research (closed access): “Association of Healthy Lifestyles with Risk of Alzheimer Disease and Related Dementias in Low-Income Black and White Americans” by Jae Jeong Yang et al., Neurology; and “Association of Diabetes and Hypertension With Brain Structural Integrity and Cognition in the Boston Puerto Rican Health Study Cohort” by Yi Guan et al., Neurology.
Abstract — Healthy Lifestyles and ADRD Risk
Objective: Epidemiologic evidence about lifestyle factors and Alzheimer’s disease and related dementias (ADRD) is limited for non-White and low-income groups who face disproportionate disease burdens. This cohort study examined associations of five lifestyle factors—smoking, alcohol use, leisure-time physical activity, sleep hours and diet quality—individually and combined, with ADRD risk among socioeconomically disadvantaged Americans.
Methods: Using Medicare claims to identify incident ADRD among Southern Community Cohort Study participants aged 65+, researchers scored each lifestyle factor as unhealthy, intermediate or healthy and summed these into a composite score. Cox regression estimated hazard ratios for ADRD, treating death as a competing risk.
Results: Among 17,209 participants followed for a median of 4.0 years, 1,694 developed ADRD (mean age at diagnosis 74.0 years). Healthy behaviors were each associated with an 11%–25% lower ADRD risk. The composite lifestyle score showed a dose-response association with up to a 36% reduced ADRD risk across quartiles, independent of sociodemographic and clinical factors.
Conclusion: Promoting healthy lifestyles and reducing barriers to adopting those behaviors could substantially help prevent ADRD and narrow disparities among socioeconomically disadvantaged populations.
Abstract — Diabetes, Hypertension, Brain Structure and Cognition
Background and Objectives: The Boston Puerto Rican Health Study (BPRHS) follows Puerto Rican older adults in Greater Boston, a group with higher prevalences of hypertension (HTN) and type 2 diabetes (T2D) than age-matched non-Hispanic White adults. This study assessed how HTN and T2D, alone and together, relate to brain structural integrity and cognitive function, and compared findings with older adults from other research cohorts.
Methods: BPRHS participants who completed brain MRI and cognitive testing were categorized by HTN and T2D status. Researchers evaluated white-matter microstructure via diffusion MRI, hippocampal volumes, brain age estimates, and cognitive scores, then compared results with data from other cohorts.
Results: HTN and T2D prevalences were substantially higher in the BPRHS than in ADNI non-Hispanic White participants. Individuals with both HTN and T2D showed the greatest white-matter deterioration, smallest hippocampal volumes and larger brain-age deviations, with trends toward lower executive function and global cognition. Imaging and cognitive patterns in the comorbid group resembled those seen in progressive mild cognitive impairment in other cohorts.
Discussion: The combination of T2D and HTN appears to produce greater brain structural disruption than HTN alone. The high prevalence of these conditions in the Puerto Rican population may contribute to observed disparities in cognitive impairment relative to non-Hispanic White adults. Trial registration: ClinicalTrials.gov identifier: NCT01231958.