Controllable risk factors that factor into Alzheimer’s or dementia cases play varying roles based on someone’s race and ethnicity, a new study shows.
About 23% of people who have Alzheimer’s disease or a related dementia in their 60s or later also have risk factors such as diabetes, high blood pressure or not getting enough exercise. But that percentage can vary based on race or ethnicity, according to a study published Wednesday in Neurology. Researchers also took into account APOE ε4, a gene variant linked to increased risk for developing Alzheimer’s disease at a late age.
“There is no cure for Alzheimer’s disease, so preventing or delaying this disease and other related forms of dementia by reducing controllable risk factors is an urgent public health priority,” Unhee Lim, PhD, the study’s author and a researcher at the University of Hawaii at Manoa in Honolulu, said in a statement. “Our study found not only does the percentage of cases linked to controllable risk factors vary by race and ethnicity, so do the most prevalent risk factors for each group.”
Data came from 91,881 participants who were part of the larger Multiethnic Cohort Study. The average age was 59, and people didn’t have dementia when the study began. Of the participants, 34% were Japanese American, 28% were white, 19% were Latino, 12% were Black, and 7% were Native Hawaiian. All of them completed questionnaires about their medical history, sleep and activity levels, diet, and medications they took. Based on their addresses, researchers were able to identify socioeconomic factors such as their income, employment and housing quality.
After following up for an average of nine years, 16,507 of the people went on to be diagnosed with Alzheimer’s disease or related dementia at age 60 or older. Of them, 24% were Black and 14% were native Hawaiian.
Researchers evaluated the percentage of cases that could be attributed to known risk factors including the gene variant APOE ε4. The team found that 31% of cases could be linked to known risk factors such as smoking, obesity, less education, high blood pressure, heart disease, stroke and diabetes, to name a few. The percentage of cases was similar between men and women. But when the team evaluated racial and ethnic groups, they started to see disparities.
Controllable risk factors accounted for 33% of cases among Latinos, 29% among Native Hawaiians, 28% among Black people, 22% among white people and 14% of cases among Japanese Americans.
The team also found which risk factors were the top ones based on race and ethnicity. For Latinos, diabetes was the top risk factor and was present in 7% of cases. Among Black, Native Hawaiian and white people, low socioeconomic status was the top risk factor, accounting for 6%, 5% and 4% of cases, respectively. Physical inactivity accounted for 4% of Japanese Americans.
“Our findings confirm that less education, low socioeconomic 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,” Lim said. “Our findings call out the need for tailored interventions for various racial and ethnic groups, specific to more prevalent risk factors. Our findings also highlight the importance of discovering other risk factors in racial and ethnic groups whose cases are not as well explained by known risk factors.”
