Limited Evidence Exists for Alzheimer's Risk Factors

However, some evidence indicates healthy lifestyle may still help in preventing the disease

WEDNESDAY, May 11 (HealthDay News) -- The existing evidence is insufficient to draw firm conclusions about the association of any modifiable factor with the risk of Alzheimer's disease (AD), according to a study published online May 9 in the Archives of Neurology.

Martha L. Daviglus, M.D., Ph.D., from Northwestern University Feinberg School of Medicine in Chicago, and colleagues examined the available evidence to identify any association of modifiable factors with the risk of AD. The data were gathered from an evidence report composed of English-language publications in MEDLINE and the Cochrane Database of Systematic Reviews from 1984 through Oct. 27, 2009. Studies including participants aged 50 years and older from general populations in developed countries were included. The minimum sample sizes were 300 for cohort studies and 50 for randomized controlled trials with at least two years between exposure and outcome assessment. Each factor was characterized as low, moderate, or high based on the overall quality of the evidence.

Investigators found that an increased risk of AD was associated with diabetes mellitus, hyperlipidemia in midlife, and current tobacco use. Mediterranean-type diet, folic acid intake, low or moderate alcohol intake, cognitive activities, and physical activity were correlated with a reduced risk. However, for all these factors, the quality of evidence of association was low.

"Until more conclusive results are available, individuals should continue to aim for a physically and mentally active and healthy lifestyle and prevention of the well-known major risk factors for chronic diseases," the authors write.

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