A massive new study gives specifics into the lack of diversity in Alzheimer’s disease research.
Researchers examined 11,871 research articles on Alzheimer’s disease brain imaging to explore the gap in representation. In studies, minorities were underrepresented. Anywhere from 84% to 87% of study participants were non-Hispanic white people in the two types of studies they assessed. Non-Hispanic white people make up less than 60% of the US population.
“As far as we know, this is the most comprehensive review of representation in the Alzheimer’s disease neuroimaging literature,” Duke Han, PhD, a senior author and professor of family medicine, neurology, psychology and gerontology at the Keck School of Medicine, said in a statement. “It gives us a good sense of the current state of the literature and what needs to be addressed moving forward.”
The team looked at 719 studies that reported on race or ethnicity — which they called direct studies — and 1,745 studies that used external databases where race or ethnicity was reported — indirect studies.
All racial and ethnic minority groups — Black, Hispanic, Latino, Asian American, American Indians and Alaska Native people — were not represented as much as non-Hispanic white individuals. In direct studies, 87.4% of median study participants were non-Hispanic white, 7.3% were Black/African American, 3.4% were Hispanic/Latino, and none were Asian American, Native Hawaiian/Pacific Islander and American Indian/Alaska Native, multiracial or another race.
In the indirect studies there was a little more diversity. Of participants, 83.7% were non-Hispanic white, 11.6% were Black/African American, 4.7% were Hispanic/Latino, and 1.75% were Asian American participants.
Interestingly, 94% of indirect studies were based on the same 10 shared databases. This means that these large studies — without equal representation — are driving a large amount of research.
“This is a pretty big deal, especially as we look toward the future, where an increasing proportion of the US will be ethnic minority groups,” Aaron Lim, PhD, a postdoctoral fellow in Han’s research lab and first author of the study, said.
“If their representation isn’t adequately captured, then this disparity in research will grow and grow,” Lim said.
There are steps to enhance diversity in studies, though, the team reported. In 2020, the Alzheimer’s Disease Neuroimaging Initiative, one of the largest studies on the disease, unveiled a plan to recruit more people from minority groups. The results were recently published in Communications Medicine.
