More Evidence Physical Activity May Ward Off Dementia
Physical activity reduces the risk for cognitive impairment and vascular dementia in older, nondisabled adults with white matter changes (WMC), a new study has found.
The results were independent of the severity of WMC and were maintained even after controlling for educational level, age, temporal atrophy, and risk factors predictive of dementia, such as previous stroke and diabetes.
"Our data support the conviction that older subjects with vascular risk factors and evidence for vascular cerebral damage benefit from regular physical activity," the authors, led by Ana Verdellho, MD, a neuroscience researcher at the University of Lisbon, Santa Maria Hospital, in Portugal, conclude.
The study was published online November 1 in the journal Stroke.
LADIS Study
The Leukoaraiosis and Disability (LADIS) study is a prospective, multinational European project investigating the impact of WMC on the transition to disability in persons aged 64 to 84 years. Individuals who had minor neurological, cognitive, mood, or motor complaints that did not affect their daily living were included and evaluated at baseline and yearly for 3 years.
The analysis included 638 participants, 29.6% of whom had previously had a stroke, and 14.6% had diabetes. On the basis of magnetic resonance imaging, it was determined that 44% of the study population had mild WMC, 31% had moderate WMC, and 25% had severe WMC.
Participants were classified as being active (30 or more minutes of activity at least 3 days per week) or inactive. Close to two thirds (63.8%) performed physical activity.
Participants underwent a battery of neuropsychological tests that assessed cognitive function, orientation, language, memory, attention, speed of mental processing, and executive function. In follow-up clinical visits, cognitive status was classified as follows: dementia, cognitive impairment not dementia, or no cognitive impairment. Dementia was diagnosed in 90 patients, and 147 patients had cognitive impairment not dementia.
The study found that physical activity was an independent protective factor for cognitive impairment that was unchanged when controlling for diabetes (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.524 - 0.949; P = .021).
When considering baseline cognition (using Mini–Mental State Examination scores), physical activity remained an independent predictor of vascular dementia, halving the risk for future vascular dementia (HR, 0.49; 95% CI, 0.257 - 0.940; P = .032).
Possible explanations for the protective effect of physical activity include improved cerebral blood flow, reduced vascular risk factors, decreased secretion of stress hormones, and enhanced endothelial function, said the authors.
A limitation of the study was that the sample did not represent the community, inasmuch as participants were selected on the basis of minor complaints that brought them to seek medical attention. Another study limitation was its relatively short length.
"Convincing Evidence"
Ralph L. Sacco, MD, professor and chair of neurology, executive director of the McKnight Brain Institute, and chief of neurology at the Jackson Memorial Miller School of Medicine, University of Miami, in Florida, felt that the study showed "some convincing evidence" that physical activity in an older population reduces the risk for vascular dementia.
"Few studies have also controlled for brain imaging data and demonstrated the effects of physical activity," noted Dr. Sacco.
Physical activity is a key ingredient in the American Heart Association definition of ideal cardiovascular health and can also help reduce stroke and improve brain health, he said.
As the population ages, there will be an increasing emphasis on ways to reduce dementia and age-related cognitive decline, he added.
The LADIS Study was supported by the European Union within the Fifth Framework Programme Quality of Life and Management of Living Resources. One of the authors (Franz Fazekas, MD) reports receiving a modest research grant.
Stroke. Published online November 1, 2012. Abstract
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