A new study finds that inequality-related dementia risk is correlated with diet and other modifiable lifestyle factors
New research indicates that lifestyle aspects like diet, exercise, and sleep have a significant role in lowering the chance of developing dementia, even as the prevalence of Alzheimer’s disease and other types of dementia continue to climb in the United States. According to researchers, two recent studies provide unique insights into the elements that can contribute to dementia’s disproportionate impact among non-White and low-income U.S. populations.
“Our findings support the beneficial role of healthy lifestyles in the prevention of Alzheimer’s disease and related dementias among senior Americans, including those with socioeconomic disadvantages and a high risk of dementia,” said Danxia Yu, Ph.D., assistant professor in the Division of Epidemiology at Vanderbilt University Medical Center, the study’s lead author.
“We should recognize that it is challenging for people facing systemic and structural disadvantages to maintain healthy lifestyles or make lifestyle changes. It is critical to establish public health strategies to make lifestyle modifications achievable for all, especially disadvantaged populations.”
The results of two research were presented online by Yu and her colleagues at NUTRITION 2022 LIVE ONLINE, the American Society for Nutrition’s flagship annual meeting. The study was also recently published in Neurology, the American Academy of Neurology’s official journal.
The Southern Community Cohort Study, a long-term research project that was started in 2001 to look into the causes of numerous diseases and health disparities, is the source of the study’s findings. Around 85,000 people were recruited from community health clinics in the southern United States. Two-thirds of participants are Black, giving the study among the highest representation of African-Americans of any large U.S. research cohort. Researchers tracked Alzheimer’s diagnoses among participants over the age of 65 using Medicare claims data.
Examining five lifestyle factors
In the first study, data were collected from 17,209 older study participants, 1,694 of whom had forms of dementia such as Alzheimer’s over a median follow-up of four years. Smoking, alcohol usage, leisure-time physical activity, sleep duration, and diet quality were all examined both individually and in combination.
The results showed that healthy choices (no smoking, high leisure-time exercise, low-to-moderate alcohol consumption, adequate sleep and a high-quality diet) were individually associated with an 11-25% reduced risk of Alzheimer’s disease and related dementias. When combined, a composite score of those five lifestyle factors was associated with a 36% reduced risk in the highest versus lowest quartile. These associations were independent of participants’ age, sex, race, education, income and underlying chronic diseases.
Analyzing dietary polyphenols
For the second study, researchers drew data from 14,500 older study participants, of whom 1,402 developed Alzheimer’s or related dementias. In this group, they analyzed intakes of four major classes of dietary polyphenols — flavonoids, phenolic acids, stilbenes, and lignans — and their subclasses, using a validated food frequency questionnaire and polyphenol databases. Polyphenols are a large class of compounds commonly found in tea, red wine, chocolate, berries, and other foods and have been associated with a variety of health benefits.
In this study, researchers found a significant difference in intake of polyphenols among racial groups, with White participants consuming a median of about twice the amount of total polyphenols as Black participants daily. Overall there was no significant association between total dietary polyphenol intake and incidence of Alzheimer’s disease and related dementias in either race; however, certain flavonoids were associated with reduced risk among Black participants but not White participants. The findings showed Black participants in the top quartile for tea consumption had a 28% lower incidence of Alzheimer’s than Black participants in the lowest quartile for tea consumption.
While both studies are observational and did not assess the mechanisms behind the associations, researchers said that healthy lifestyles, including healthy eating, may help protect brain health by improving glucose and lipid metabolism and reducing inflammation and psychological stress. Yu said more research is needed to further elucidate the relationship between lifestyle factors and Alzheimer’s disease among diverse populations.
“Black Americans and people with low socioeconomic status are disproportionately affected by the disease but have been largely underrepresented in epidemiologic studies,” Yu said. “Identifying modifiable factors for the prevention of Alzheimer’s disease and related dementias among low-income people of different races and ethnicities is a critical public health issue.”
Meeting: NUTRITION 2022 LIVE ONLINE
Reference: “Association of Healthy Lifestyles with Risk of Alzheimer Disease and Related Dementias in Low-Income Black and White Americans” by Jae Jeong Yang, Laura M Keohane, Xiongfei Pan, Ruiqi Qu, Xiao-Ou Shu, Loren P Lipworth, Kyle Braun, Mark D Steinwandel, Qi Dai, Martha Shrubsole, Wei Zheng, William J Blot and Danxia Yu, 13 June 2022, Neurology.