Alzheimer's Affects Black and White Brains Differently, Study Says

Alzheimer’s disease causes deteriorating changes in the brain. But those changes may be different for people of different races, according to a new study released today.

Three-quarters of African-American Alzheimer’s patients analyzed post-mortem were found to have a mingling of the plaques and tangles representative of the disease mixed with other signs of disease: stroke-signaling infarcts and Lewy bodies, often associated with dementia and Parkinson’s, according to the study, published online today in the journal of the American Academy of Neurology.

The study began in response to several other scientific conclusions suggesting that the disease was more common among African Americans, said Lisa Barnes, the author, from Rush University Medical Center in Chicago.

“Our study has important clinical implications because it may suggest a need for different types of Alzheimer’s prevention and treatments in African Americans,” she said.

“Given the mixed pattern of disease that we see in African-American brains, it will be important to develop new treatments that target these other common pathologies, particularly for African Americans,” Barnes added.

The scientists analyzed patients with the same age, sex and education level – but of different race.

Forty-one African Americans and 81 European Americans who had diagnoses of Alzheimer’s from a memory clinic had autopsies after dying.

Half of those from European descent had pure Alzheimer’s in their brains – the plaques and tangles characteristic of the disease. But only a quarter of those of African descent had Alzheimer’s pathology alone in their gray matter; roughly 71 percent of this patient group had a mix of the other brain disorders, and they also tended to have more frequent and severe blood-vessel disease, said Barnes.

“Studying how Alzheimer’s looks in the brain in individuals of different races may help us to further understand the disease and pinpoint strategies for prevention and treatment,” Barnes added.

Race has been noted as a factor in the prevalence of many disease – particularly cardiovascular. But diabetes, high blood pressure, kidney disease and other afflictions like lung disease have also been noted to be more frequent in the African-American population. Potential factors have included genetics, diet, and smoking factors in these racial disparities.