Mediterranean Diet Reduces Cerebrovascular Disease -- Synopsis

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February 9, 2010 -- Magnetic resonance images (MRIs) have confirmed that the Mediterranean diet decreases cerebrovascular disease. Investigators suggest this reduced risk may also lessen cognitive decline later in life.

"The impact of the Mediterranean diet on cognition may be partially mediated by brain infarction," said lead investigator Nikolas Scarmeas, MD, from the Taub Institute Division of Aging and Dementia at Columbia in New York.

"This group of investigators has reported on this same cohort many times," David Knopman, MD, from the Mayo Clinic in Rochester, Minnesota, told Medscape Neurology. "But this study, in which they performed MR scans, adds something new," specifically that evidence of infarcts on scans was influenced by adherence to the Mediterranean diet.

"This is something that people suspected," Dr. Knopman added, "but this is the first firm evidence that the mechanism of benefit conferred by adherence to the Mediterranean diet is reduction in cerebrovascular disease."

The new study will be presented in April at the American Academy of Neurology Annual Meeting in Toronto, Ontario, Canada, and was released February 8. The abstract will post to http://www.aan.com on February 17.

The study involved more than 700 participants in the Washington Heights-Inwood Columbia Aging Project.

Investigators collected high-resolution structural MRIs and assessed about 5 years worth of dietary reports. The researchers divided participants into 3 groups — low, moderate, and high adherence to the Mediterranean diet.

"We examined the association of increasing adherence to the diet with presence of infarcts and total white matter hyperintensity volume on MRI," Dr. Scarmeas explained.

In all, 238 participants had at least 1 infarct. Most patients had a small infarct measuring less than 1 cm. But 40 patients had a large infarct measuring 1 cm or more. Another 31 patients had both small and large infarcts.

Compared with participants in the low adherence group, those in the moderate group had a 21% reduced risk of having an infarct. Participants in the highest adherence group had the lowest rate, a 36% reduction vs those with low adherence to the diet.

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Table. Risk for Infarct by Adherence to Mediterranean Diet

Adherence to the Mediterranean Diet / Odds Ratio (95% Confidence Interval)

Moderate / 0.79 (0.55 – 1.14), p = 0.203

High / 0.64 (0.42 – 0.98), p = 0.038
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"Models were run without adjustment," Dr. Scarmeas noted. Others were adjusted for basic demography, including age, sex, education, and ethnicity, he added. Another model was adjusted for vascular risk factors, such as apolipoprotein E4, body mass index, caloric intake, diabetes, heart disease, hypertension, smoking history, and cholesterol.

In both adjusted models, the strength of the association between the Mediterranean diet and infarct remained essentially unchanged.

"The association of high Mediterranean diet adherence with infarcts was comparable to that of hypertension at a 35% reduced probability," Dr. Scarmeas reported. It was stronger in women than men (45% vs 15.6%) and did not vary by infarct size. This rate also did not change after excluding patients with dementia (n = 46) or clinical strokes (n = 88).

There was no relationship between Mediterranean diet adherence and white matter hyperintensity volume, they note.

Dr. Knopman applauded the work. "Imaging studies in a population-based study is a great strength," he said. "The results reinforce the notion that a healthy lifestyle protects the brain and the heart."

Dr. Knopman says he would like to see this study replicated in other populations with different dietary norms.

The researchers have disclosed no relevant financial relationships.

American Academy of Neurology (AAN) 62nd Annual Meeting: Abstract 3520. Presented April 10-17, 2010.

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Authors and Disclosures

Allison Gandey is a journalist for Medscape. She is the former science affairs analyst for the Canadian Medical Association Journal. Allison, who has a master of journalism specializing in science from Carleton University, has edited a variety of medical association publications and has worked in radio and television. She can be contacted at agandey@webmd.net.

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