An association between variety of activity and dementia risk, however, did not hold up in those with the so-called APOE-4 genetic predisposition to the disease found in about one-quarter to one-third of Alzheimer's patients, according to a report by researchers at the Johns Hopkins Medical Institutions.

General physical activity is already known to enhance cardiovascular health and help maintain independence and quality of life in older people, but the results of this study - which establish a statistical association, and not a direct cause and effect, between variety of exercise and reduced dementia risk - suggest that participating in a number of different activities may be as or more important than frequency, duration, and intensity of physical activity with respect to dementia risk, according to the report.

The study included 3,375 men and women aged 65 years and older. The researchers found 480 new cases of dementia over an average of 5.4 years of follow-up. Among these, dementia occurred less frequently in those participating in more activities relative to those who participated in fewer activities.

The association held true for all types of dementia, including Alzheimer's disease and vascular dementia. The association did not hold true for those who have the APOE-4 genotype.

"These findings, taken together with recent findings from our colleagues at the University of Chicago studying physical activity and plaque build-up in the brains of mice with Alzheimer's (published this year in the journal Cell) provide a good picture from basic and clinical science of how activity and exercise work to reduce the risk of dementia," says Constantine Lyketsos, professor of psychiatry and behavioural sciences at Johns Hopkins and senior author on the report.

MEDICA.de; Source: Johns Hopkins Medical Institutions