Prashanthi Vemuri, Ph.D.

People who keep mentally and physically fit in middle age may not show symptoms of Alzheimer’s disease, but that doesn’t mean that such activity affects the underlying disease changes in the brain, according to a study published in the Feb. 24 online edition of Neurology, the medical journal of the American Academy of Neurology.

Despite the study’s findings, said author Prashanthi Vemuri, Ph.D., of the Mayo Clinic in Rochester, MN, people should not be discouraged from exercising and participating in activities such as reading books and magazines, playing games and using computers. “There is substantial evidence that these activities help to delay the onset of memory and thinking problems,” she said. “What we don’t know is how this process works.”

The researchers evaluated 393 people, all aged 70 of more years and without dementia, although 53 had mild cognitive impairment. Participants were divided into two groups, those who had more than 14 years of formal education and those who had fewer years of formal education.

Researchers used magnetic resonance imaging and positron emission tomography to look for biomarkers of Alzheimer’s disease and used questionnaires to evaluate weekly intellectual and physical activity of participants in middle age.

For the group as a whole, education, occupation and mental and physical activity in middle age appeared to have little to no effect on the rates of worsening amyloid plaques, brain glucose metabolism and brain volume. Carriers of the APOE4 gene with high education and continued lifetime learning, however, had less amyloid deposition in the brain than those with high education who did not continue to learn.

“It is possible those who did not continue intellectual activity in middle age did so because they had higher levels of amyloid plaques,” Vemuri said. “While there are many limitations with this study, our findings show further study is needed and suggest that differing education levels in other recent studies may explain the conflicting results seen in the research literature.”

About 20% of the population carries the APOE4 gene, which is linked to Alzheimer’s disease.