Intellectual activity may delay Alzheimer's, but has minimal effect on overall disease

Lifestyle enrichment, including education, occupation and middle-age cognitive and physical activity, had little effect on the worsening of Alzheimer’s disease biomarker trajectories, but was associated with lower levels of the protein amyloid in the APOE4 gene, according to data published in Neurology.

“Better intellectual and physical activity lifestyles have increasingly been viewed as protective strategies against cognitive decline in the elderly,” Prashanthi Vemuri, PhD, from the department of radiology at the Mayo Clinic, in Rochester, Minnesota, and colleagues wrote. “While lifestyle enrichment is associated with better cognitive performance, there is no clear consensus on the influence of lifestyle enrichment on ongoing Alzheimer’s disease pathophysiology through longitudinal biomarker studies.”

To determine the effects of age, sex, and APOE4 genotype, as well as education, occupation and middle-age cognitive and physical activity, on the biomarker trajectories of Alzheimer’s disease (AD), the researchers used longitudinal imaging data of elderly individuals without dementia. They studied 393 participants aged 70 years and older in the population-based Mayo Clinic Study on Aging, including 340 who were clinically normal and 53 with mild cognitive impairment. Participants who were included had cognitive and physical activity measured and at least two sets of AD biomarker measurements.

The researchers split the participants into either a high education group, with 14 or more years of schooling, or low education group, with less than 14 years. They then built linear mixed models for the entire cohort and the two education groups, to determine the effect of lifestyle enrichment and other factors on each of the AD biomarker outcomes.

According to the researchers, amyloid and neurodegeneration trajectories were associated with age. In addition, APOE4 status seemed to influence only the amyloid and fluorodeoxyglucose (FDG) trajectories, but not hippocampal volume trajectory. Among those in the high education group, high middle-age cognitive ability was linked to lower amyloid deposition in APOE4 carriers. “APOE4 status was associated with lower FDG uptake in the entire cohort and among those with the low education group, but not the high-education cohort,” the researchers wrote.

“We observed minimal effects of lifestyle enrichment variables (education/occupation, midlife cognitive activity and midlife physical activity) on the AD biomarker trajectories (specifically the rate of worsening),” Vemuri and colleagues wrote. “Highly educated APOE4 carriers with high midlife cognitive activity have lower amyloid burden than highly education APOE4 carriers with low midlife cognitive activity. Age was associated with both amyloid and neurodegeneration biomarker trajectories; APOE4 status appears to influence only the FDG trajectories but not hippocampal volume trajectory. APOE4 status was not associated with lower FDG uptake in the high education cohort but was associated with lower FDG uptake in the entire cohort and lower education cohort.” – by Jason Laday

Disclosure: Vemuri reports receiving research funding from the NIH’s National Institute on Aging. Please see the full study for a list of all other authors’ relevant financial disclosures.