Asian Americans have lowest incidence of dementia in US: study

Asian Americans have the lowest incidence of dementia among different ethnic and racial groups in US, according to the first study to look at the risk of the disorder in a large population representing the diversity of the country.
It is the largest and longest study so far of ethnic disparities in dementia risk, researchers said.
Researchers from University of California, San Francisco compared six ethnic and racial groups within the same geographic population and found significant variation in dementia incidence among them.
They found dementia incidence to be highest in blacks and American Indian/Alaska Natives, lowest among Asian Americans, and intermediate among Latinos, Pacific Islanders and whites.

The researchers found that dementia incidence over the study period ranged from an average annual rate of 26.6 cases per 1,000 for blacks, and 22.2 cases per 1,000 for American Indians/Alaskan Natives, to 15.2 cases per 1,000 for Asian Americans.
In between were Latinos and Pacific Islanders with an average annual rate of 19.6 cases per 1,000, and whites with 19.3 per 1,000.

Using cumulative risk estimates, researchers projected that among those who reach age 65 dementia-free, 38 per cent of blacks, 35 per cent of American Indians/Alaskan Natives, 32 per cent of Latinos, 30 per cent of whites, 28 per cent of Asian Americans and 25 per cent of Pacific Islanders would develop dementia in the next 25 years.

"Most research on inequalities in dementia includes only one to two racial and ethnic groups, primarily whites and blacks," said lead author Elizabeth Rose Mayeda, postdoctoral fellow at University of California, San Francisco.
"This is the only research that directly compares dementia for these six racial and ethnic groups, representing the true ageing demographic of the US in a single study population," Mayeda said.
The study population included more than 274,000 California members of Kaiser Permanente, a private healthcare system.
The researchers used electronic health records covering patient visits over 14 years - from January 2000 through December 2013 - to identify participants diagnosed with dementia, as well as their race and ethnicity.

The dementia diagnoses were Alzheimer's, vascular dementia or non-specific dementia.
"Even in the lowest risk groups in the study, the lifetime risk of developing dementia is high - 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," said principal investigator Rachel Whitmer, from the Kaiser Permanente Division of Research.
"This study has major public health implications. If all individuals aged 65 or older had the same rate of dementia as Asian Americans, 190,000 cases of dementia would be prevented annually," Whitmer said.
The study was published in Alzheimer's and Dementia: The Journal of the Alzheimer's Association.