Scant Evidence Links Any Factor to Alzheimer's Prevention
Review, NIH statement say evidence of benefit from exercise, Mediterranean diet is weak
TUESDAY, June 15 (HealthDay News) -- There is scant evidence that any one factor -- such as exercising or following a Mediterranean diet -- is protective of cognitive decline, including Alzheimer's disease (AD), in older adults, according to a review presented at a National Institutes of Health State-of-the-Science Conference and a subsequent conference statement, both published online June 14 in the Annals of Internal Medicine.
Brenda L. Plassman, Ph.D., of Duke University Medical Center in Durham, N.C., and colleagues reviewed 127 observational studies, 22 randomized controlled trials, and 16 systematic reviews conducted from 1984 through 2009 on cognitive decline in AD and related nutritional, medical, behavioral, social, environmental, and genetic factors. For most factors, there was insufficient evidence to indicate an association with AD and cognitive decline. However, the apolipoprotein E e4 genotype, tobacco use, and some medical conditions were associated with increased risk. The authors conclude that there is insufficient evidence to recommend specific interventions or lifestyle changes to prevent AD.
Following the conference, an independent panel issued a state-of-the-science statement, concluding that the evidence linking any modifiable risk factor with AD and cognitive decline is inconclusive, that there is a lack of reliable diagnostic criteria, and that there is insufficient evidence to support medications or diet supplements to prevent AD or cognitive decline.
"Therefore, large-scale population-based studies and randomized controlled trials are critically needed to investigate strategies to maintain cognitive function in individuals at risk for decline, to identify factors that may delay the onset of AD among individuals at risk, and to identify factors that may slow the progression of AD among individuals already diagnosed with the disease," write the authors of the conference statement.
One author in the Plassman study reported receiving grant support from, and serving as a consultant for, pharmaceutical companies.