MONDAY, Feb. 15, 2016 (HealthDay News) -- Dementia rates can vary significantly among Americans of different racial and ethnic groups, even if they're in the same region of the country, a new study finds.
Researchers analyzed data on more than 274,000 people from six racial and ethnic groups in Northern California who were members of Kaiser Permanente, a large private health care system.
Using records of patient visits, the researchers found that the average annual rate of dementia was 26.6 cases per 1,000 for blacks; 22.2 per 1,000 for American Indians/Alaskan Natives; 19.6 per 1,000 for Hispanics and Pacific Islanders; 19.3 per 1,000 for whites; and 15.2 cases per 1,000 for Asian-Americans.
The researchers calculated that among people who reach age 65 without dementia, 38 percent of blacks, 35 percent of American Indians/Alaskan Natives, 32 percent of Hispanics, 30 percent of whites, 28 percent of Asian-Americans and 25 percent of Pacific Islanders would develop dementia in the next 25 years.
The study was published online Feb. 10 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.
"Most research on inequalities in dementia includes only one to two racial and ethnic groups, primarily whites and blacks," said study lead author Elizabeth Rose Mayeda. She is a postdoctoral fellow in the University of California, San Francisco's Department of Epidemiology and Biostatistics.
"This is the only research that directly compares dementia for these six racial and ethnic groups, representing the true aging demographic of the United States in a single study population," she said in a Kaiser news release.
Even in the groups found to be at lowest risk, the lifetime risk of developing dementia is high, said principal investigator Rachel Whitmer, a research scientist at the Kaiser Permanente Division of Research. "In every racial and ethnic group, over one in four people who survive to age 65 can expect to be diagnosed with dementia in their lifetime."
She said the study has major public health implications. "These findings underscore the need to better understand risk factors for dementia throughout life to identify strategies to eliminate these inequalities," Whitmer said in the news release.
The next step is to learn what's behind the racial and ethnic differences in dementia rates.
"Based on the present study, we cannot determine the extent to which genetic or social and behavioral factors contribute to the observed patterns," Whitmer said. "But if social and behavioral factors are the primary pathways, these findings suggest substantial reductions in dementia incidence are possible."
The American Academy of Family Physicians has more about dementia.