How dementia risk varies among ethnic groups

  • A very large U.S. study looking at ethnic differences in dementia risk, has found that African-Americans show the highest rates of dementia, followed by blacks and American Indian/Alaska Natives, then Latinos and whites, with Asian-Americans having the lowest rates.

A study involving 14 years of health records from more than 274,000 Northern Californians has assessed the relative dementia risk of six different ethnicities.

The average annual rate of dementia was:

  • 26.6 cases per 1,000 for blacks
  • 22.2 cases per 1,000 for American Indians/Alaskan Natives
  • 19.6 cases per 1,000 for Latinos and Pacific Islanders
  • 19.3 cases per 1,000 for whites
  • 15.2 cases per 1,000 for Asian Americans.

But this is an annual rate, not particularly useful at a practical level. How do these numbers convert to lifetime risk? Statistical calculations estimate that among those who reach age 65 dementia-free, the following percentages of each ethnicity will develop dementia in the next 25 years:

  • 38% of blacks
  • 35% of American Indians/Alaskan Natives
  • 32% of Latinos
  • 30% of whites
  • 28% of Asian Americans
  • 25% of Pacific Islanders (this is probably the least reliable number, given the small number of Pacific Islanders in the sample).

The study population included 18,778 African-Americans, 4543 American Indians/Alaskan Natives, 21,000 Latinos, 206,490 white Americans, 23,032 Asian-Americans, and 440 Pacific Islanders.

http://www.eurekalert.org/pub_releases/2016-02/kp-lsf021016.php

Reference: 

[4056] Mayeda, E. Rose, M. Glymour M., Quesenberry C. P., & Whitmer R. A.
(2016).  Inequalities in dementia incidence between six racial and ethnic groups over 14 years.
Alzheimer's & Dementia: The Journal of the Alzheimer's Association.