Source: DGNews  |  Posted 2 years ago

By Ed Susman

VIENNA, Austria -- July 13, 2009 -- Taking supplements of docosahexaenoic acid (DHA) does not slow progression among patients diagnosed with Alzheimer's disease, researchers reported here at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD).

"The primary implication of this study is that we are not going to be able to make a recommendation for DHA in the aggregate for people with Alzheimer's disease," said Joseph Quinn, MD, Oregon Health & Sciences University, Portland, Oregon, on July 12.

However, Dr. Quinn said that a subgroup of patients who were identified as not having the apolipoprotein E4 gene did show an advantage for having taken DHA supplements.

"In this exploratory analysis there appeared to be a benefit of DHA in that subpopulation," he said. However, he said the researchers are interpreting the finding cautiously, and are using the findings as a guide to future studies.

In the trial, patients (n = 402) diagnosed with mild to moderate Alzheimer's disease were assigned to receive either DHA or placebo.

After 18 months, researchers observed an 8-point decline in the Alzheimer's Disease Assessment Scale-cognitive score in both patients receiving DHA and those on placebo (P = .407).

There was an 11-point decline in Activities of Daily Living scale among those on placebo compared with a 10-point decline among those on DHA (P = .377). Behavioural symptom scores increased by 4 points among patients on placebo and 2 points among those on DHA (P = .108).

However, Dr. Quinn said that when patients were stratified by whether they had the apolipoprotein E4 gene, those without the gene showed about a 10-point increase in the scale measuring worsening of memory or thinking processes compared with a 5-point increase among those receiving DHA (P = .028), suggestive of an impact with DHA.

He said that because the finding was not a primary endpoint, the result would only be useful for hypothesis-generating purposes.

Funding for this study was provided by the National Institute on Aging and Martek Biosciences Corporation.

[Presentation title: A Clinical Trial of Docosahexanoic Acid (DHA) for the Treatment of Alzheimer's Disease. Abstract 09-A-875]