CULTURE & COGNITION|
Education Is Key to Reducing Disparities in Alzheimer’s
Everyone typically has a bit of memory decline with age, though it’s unclear what exactly causes some people to develop Alzheimer’s disease. Recent research has shown that certain racial and ethnic groups have a much higher risk of developing this neurodegenerative disease, but in these cases biology might be only part of the puzzle.
Dr. Jennifer Manly is a neuropsychologist who has been studying the racial disparities of Alzheimer’s patients for more than 25 years near Columbia University Medical School. Her focus area is Washington Heights, a diverse neighborhood in northern Manhattan that’s home to many African Americans who were born and raised in the south—a geographic feature that’s integral to her study—and Caribbean Hispanic immigrants.
“It’s an incredible place to do research on aging and ask questions about how culture affects the cognitive aging process,” said Manly at the Oct. 18 lecture, organized by the National Institute on Aging.
As lead investigator on the WHICAP [Washington Heights-Inwood Columbia Aging Project] study, Manly and her colleagues have evaluated more than 6,500 seniors in their homes, conducting a cognitive test battery and extensive medical and functional interviews, then following up with them every 18-24 months. Based on cohort studies that began in 1992, WHICAP data revealed that African Americans and Caribbean Hispanics have a significantly higher risk for Alzheimer’s disease and a more rapid cognitive decline over time than do whites. Other studies have corroborated this finding.
Although they’re at higher risk, racial and ethnic minorities tend to be underdiagnosed and undertreated, including many of those living in Washington Heights. Wary of the health care system, African Americans and Latinos are less likely to come to memory disorder clinics, which can skew Alzheimer’s study data. To help prevent this selection bias, WHICAP chose to conduct research in patients’ homes.
“There’s a danger in making conclusions about Alzheimer’s...based on people who were largely recruited through clinics,” said Manly. “One of the reasons there’s a bias in these types of studies is that there’s continuing mistrust of research and also stigma associated with cognitive impairment and dementia in some of the communities we’re hoping to engage and involve.”
For minority communities, past medical abuses still loom large. Even if ethical and legal standards now exist to help prevent mistreatment, said Manly, “African Americans, Hispanics and American Indians continue to experience everyday lack of cultural and linguistic competency in the health care system, so it’s not something in the past. The source of mistrust of research is here and now.”
When minorities do visit clinics, said Manly, they tend to be in later stages of dementia, which becomes more costly to treat and a greater burden on caregivers. The challenge is finding ways to engage at-risk patients much earlier.
“When we start brain imaging at age 70, it’s too late,” said Manly. “We need imaging earlier in life to uncover what some of the causes and influences are on development of neuropathology in the brain.”
Interestingly, in African Americans, the presence of more white matter hyperintensities in the brain have been linked to cognitive decline, whereas for whites, below average hippocampal volume was tied to dementia. This suggests there may be different pathways to Alzheimer’s disease, said Manly.
In addition to biological or genetic factors, Manly’s research indicates that racial disparities in Alzheimer’s can be attributed to socio-economic and cultural factors.
“African ancestry and racial/ethnic self-identification are markers for individual social experiences, as well as those of your parents and grandparents, such as discrimination, segregation and socio-economic status.”
Manly argues that educational experience, particularly the quality of schooling and literacy, has a powerful influence on later-life cognitive decline. In historical data from 1919 to 1951, African-American students in the south not only had much larger class sizes (student/teacher ratio), but also their schools were only open half as often as schools for whites in the same state or in northern schools.
“In these analyses, the disparities in developing Alzheimer’s disease across race are accounted for by indicators of school quality,” said Manly. “I think that educational experience, not just years of school, is a pathway through which disparities in dementia emerge.”
While further study is needed, Manly noted a declining trend of dementia among African Americans that corresponded to compulsory school law changes and higher reading levels.
One of her newer studies is tracking down some of the 400,000 high school participants from the 1960 Project Talent study, who would now be in their 70s, to help gauge the effect of school quality on racial disparities in Alzheimer’s disease.
More representative studies are needed, she said, that incorporate cognitive testing, imaging of neuropathology and measures of educational experience. Coupled with interventions earlier in life, such research can help prevent the Alzheimer’s epidemic from having a disproportionate effect on people of color.