A healthy lifestyle may preserve cognitive function even in Alzheimer's disease

Autopsy data showed that older adults with healthy lifestyles had better cognitive function, even if they had Alzheimer's disease or other dementia-related conditions.

A 1 point increase in healthy lifestyle score was associated with improved cognitive performance near death (β=0.216, P<0.001), reported Klodian Dhana, MD, PhD, of Rush University Medical Center in Chicago, and co-authors.

After adjusting for β-amyloid burden, healthy lifestyle score was still independently associated with cognitive function (β=0.191, P<0.001), the researchers reported: JAMA Neurology.

Similarly, after adjusting for phospho-tau tangle pathology, scores were independently associated with cognition (β=0.196, P<0.001) or overall Alzheimer's disease pathology (β=0.193, P<0.001). Lifestyle scores range from 0 to 5 points, with higher scores indicating a healthier lifestyle.

“There are many epidemiological studies, including ours, that support the role of lifestyle in dementia risk,” Dana said. today's med page. “However, as individuals age, dementia-related brain lesions such as beta-amyloid gradually accumulate, and whether their lifestyle is related to cognition independent of dementia-related brain pathology. There are questions.”

In 2020, lancet committee They reported that up to 40% of dementia cases could be prevented or delayed by improving 12 risk factors, but a healthy lifestyle can help improve “cognitive reserve,'' or cognitive decline despite brain pathology. It is not clear whether the ability to maintain force can be increased.

Yue Leng, PhD, and Kristine Yaffe, MD, of the University of California, San Francisco, say the study could help researchers better understand how modifiable risk factors are associated with dementia. , said in an accompanying editorial.

“Over the past decade, research has identified an increasing number of new risk factors for dementia, and we are beginning to uncover the mechanisms by which these modifiable risk factors influence cognitive aging and prompt multidomain interventions.” write Wren and Yaffe. “Despite this ongoing progress, important questions remain regarding the mechanistic pathways linking modifiable risk factors and cognitive aging and the direction of this association.”

The study is “one of the first to use brain pathology to investigate these mechanisms, and is an important step forward in addressing these important questions,” the editorial authors noted. . “Better designed randomized clinical trials are urgently needed to pave the way for dementia risk reduction in the era of precision medicine.”

Dhana and colleagues used data from the Rasch Memory and Aging Project, a longitudinal study that included up to 24 years of follow-up and autopsy data. Researchers examined dietary and lifestyle data, cognitive tests just before death, and postmortem findings of 586 people who died. Most of the deaths (70.8%) were women, and the average age at death was 90.9 years.

Lifestyle factors are assessed annually and are based on MIND dietary adherence, late-life cognitive activity scores, no current smoking, at least 150 minutes of moderate or vigorous physical activity per week, and light to moderate alcohol intake. considered risky or “healthy”. To reduce reverse causality, the mean of each lifestyle factor from admission to study to death was calculated.

Cognitive function was measured at 19 examinations each year. The researchers used pre-death global cognitive scores in this analysis. Median time from last cognitive assessment to death was 0.8 years.

Postmortem beta-amyloid was assessed in multiple brain regions, as was phospho-tau tangle density. Atherosclerosis, arteriosclerosis, microinfarcts, macroinfarcts, cerebral amyloid angiopathy, Lewy body disease, hippocampal sclerosis, and TAR DNA binding protein 43 (TDP-43) were also evaluated.

The higher the lifestyle score, the lower the beta-amyloid burden in the brain (β = −0.120, P=0.003), the researchers reported. The overall estimated association of lifestyle score on cognition was 0.216, and the indirect association via beta-amyloid burden was 0.025 (P=0.008), or 11.6%.

Although the estimates were reduced by excluding those with poor cognition at baseline or those with clinical Alzheimer's dementia near death, the association between lifestyle scores and cognition remained statistically significant. It was unrelated to general brain pathology.

Dana noted that the findings suggest that lifestyle may have cognitive benefits even for people who are beginning to accumulate dementia-related conditions. “However, it should be noted that this is an observational study using pathological data at autopsy, and additional clinical studies are needed to corroborate these findings,” he said.

The study sample consisted primarily of white volunteers who consented to annual evaluations and postmortem organ donation, limiting the generalizability of the results to others, the researchers acknowledged. In addition, lifestyle factors were also self-reported.