Variation of Dementia Risk Factors by Race and Ethnicity: An Examination of Controllable Risks

New Study Reveals Variation in Alzheimer's Risk Factors Across Racial and Ethnic Groups

A new study, published in the online issue of Neurology, has shed light on the varying risk factors for Alzheimer's disease and related dementias across different racial and ethnic groups. Funded by the National Cancer Institute and the National Institute on Aging at the National Institutes of Health, the study involved 91,881 participants from the Multiethnic Cohort Study, with an average age of 59 and no history of dementia at the study's start.

After an average follow-up period of nine years, 16,507 people were diagnosed with Alzheimer's disease or related dementia at age 60 or older. The researchers determined that known risk factors, including the gene variant APOE ε4, as well as 12 controllable or changeable risk factors, accounted for approximately 31% of all cases.

The most prevalent risk factors varied among the racial and ethnic groups studied. For Latinos, diabetes was the top risk factor, accounting for 7% of cases. For Black, Native Hawaiian, and White people, low socio-economic status was the top risk factor, accounting for 6%, 5%, and 4% of cases, respectively. For Japanese Americans, physical inactivity led the risk factors at 4%.

Among female participants, controllable risk factors accounted for 23% of cases, while among male participants, it was 24%. These controllable risk factors include low physical activity, less education, low socioeconomic status, a history of high blood pressure, heart disease, stroke, or diabetes, not being married as a proxy for low social contact, current smoking, too short or too long sleep, obesity, and a low-quality diet.

Dr. Lim, the study's lead author, emphasised the need for tailored interventions for various racial and ethnic groups, specific to more prevalent risk factors. He also highlighted the importance of discovering other risk factors in racial and ethnic groups whose cases are not well explained by known risk factors.

Disproportionately higher percentages of Black and Native Hawaiian people were diagnosed with Alzheimer's disease or related dementia, which the study did not fully explain. The study had a limitation of not having enough data to examine additional risk factors such as hearing impairment, depression, a history of traumatic brain injury, or exposure to air pollution.

Despite these limitations, the findings confirm that less education, low socio-economic status, and other risk factors in middle age account for substantial but varying proportions of dementia cases later in life across racial and ethnic populations. The study underscores the importance of addressing these risk factors to reduce the incidence of Alzheimer's disease and related dementias.

Variation of Dementia Risk Factors by Race and Ethnicity: An Examination of Controllable Risks