From the Journals

Dementia prevalence study reveals inequities



Dementia and mild cognitive impairment (MCI) disproportionately affect Black and Hispanic individuals, as well as people with less education, based on new U.S. data from The Health and Retirement Study (HRS).

These inequities likely stem from structural racism and income inequality, necessitating a multifaceted response at an institutional level, according to lead author Jennifer J. Manly, PhD, a professor of neuropsychology in neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer’s Disease at Columbia University, New York.

A more representative dataset

Between 2001 and 2003, a subset of HRS participants underwent extensive neuropsychological assessment in the Aging, Demographics, and Memory Study (ADAMS), providing data which have since been cited by hundreds of published studies, the investigators wrote in JAMA Neurology. Those data, however, failed to accurately represent the U.S. population at the time, and have not been updated since.

Jennifer J. Manly, PhD, is a professor of neuropsychology in neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer's Disease at Columbia University, New York.

Dr. Jennifer J. Manly

“The ADAMS substudy was small, and the limited inclusion of Black, Hispanic, and American Indian or Alaska Native participants contributed to lack of precision of estimates among minoritized racial and ethnic groups that have been shown to experience a higher burden of cognitive impairment and dementia,” Dr. Manly and colleagues wrote.

The present analysis used a more representative dataset from HRS participants who were 65 years or older in 2016. From June 2016 to October 2017, 3,496 of these individuals underwent comprehensive neuropsychological test battery and informant interview, with dementia and MCI classified based on standard diagnostic criteria.

In total, 393 people were classified with dementia (10%), while 804 had MCI (22%), both of which approximate estimates reported by previous studies, according to the investigators. In further alignment with past research, age was a clear risk factor; each 5-year increment added 17% and 95% increased risk of MCI and dementia, respectively.

Compared with college-educated participants, individuals who did not graduate from high school had a 60% increased risk for both dementia (odds ratio, 1.6; 95% confidence interval, 1.1-2.3) and MCI (OR, 1.6; 95% CI, 1.2-2.2). Other educational strata were not associated with significant differences in risk.

Compared with White participants, Black individuals had an 80% increased risk of dementia (OR, 1.8; 95% CI, 1.2-2.7), but no increased risk of MCI. Conversely, non-White Hispanic individuals had a 40% increased risk of MCI (OR, 1.4; 95% CI, 1.0-2.0), but no increased risk of dementia, compared with White participants.

“Older adults racialized as Black and Hispanic are more likely to develop cognitive impairment and dementia because of historical and current structural racism and income inequality that restrict access to brain-health benefits and increase exposure to harm,” Dr. Manly said in a written comment.

These inequities deserve a comprehensive response, she added.

“Actions and policies that decrease discriminatory and aggressive policing policies, invest in schools that serve children that are racialized as Black and Hispanic, repair housing and economic inequalities, and provide equitable access to mental and physical health, can help to narrow disparities in later life cognitive impairment,” Dr. Manly said. “Two other areas of focus for policy makers are the shortage in the workforce of dementia care specialists, and paid family leave for caregiving.”


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