People who stay mentally and physically active to fight Alzheimer's later in life may only delay the disease, not prevent it.
People who try to keep their brain cells and bones and muscles running until the middle age may hold off signs and symptoms of dementia, but in the end, Alzheimer's is still bound to happen. This is because mental and physical stimulation do not change the underlying process associated with the disease, at least for the general population.
Alzheimer's disease is characterized by the buildup of sticky amyloid plaques in the brain. Individuals who carry the gene called APOE4 are known to double their risk of Alzheimer's disease. So for them, it is very important to keep the said plaques at bay.
Inconsistent Study Findings
Study author Prashanthi Vemuri from Mayo Clinic says recent research have exhibited conflicting findings about the role of mental and physical activity in the risk of developing Alzheimer's. One striking observation they made though, is that participants in those studies have different educational levels.
With this, the team wanted to analyze the effect of sex, age, APOE4 genotype and midlife lifestyle in the development of Alzheimer's disease.
Continuity Is Key
When the researchers looked into the level of learning throughout the participant's' lifetime, they found that those with APOE4 gene who had higher education and continued mental and physical activity had fewer amyloid plaques than those who did not resort to mental activities in the middle age.
The amount of predicted amyloid plaque levels of a 79-year-old highly educated, continuous learner is the same with that of a 74-year-old who did not resort to physical and mental activities.
Such finding looks as if people can make their brains younger by five years just with continuous activity. However, the seemingly good results for APOE4 carriers do not translate to the general population.
The researchers found that continuous mental and physical activities, age, sex, occupation and education have very minimal effects on amyloid plaque development, brain volume and brain glucose regulation in non-APOE4 carriers.
Despite this, Vemuri says people without APOE4 should not be discouraged to engage in mental and physical activities in midlife.
"There is substantial evidence that these activities help to delay the onset of memory and thinking problems," she says. "What we don't know is how this process works."
How The Researchers Investigated
The study involved 393 individuals aged 70 years old and above. Although all the participants do not have dementia, 53 had mild cognitive disturbance. They were classified into two groups: the first includes those who attained education of 14 years or more, while the second had less.
The subjects underwent PET and MRI scans, which revealed Alzheimer's biomarkers. They also answered questionnaires to ascertain their mental and physical activities per week in midlife.
The study published in the journal Neurology on Feb. 24.