HONOLULU — About 23% of Alzheimer’s and related dementia cases in people 65 and older are linked to controllable risk factors such as diabetes and physical inactivity, but new research by the University of Hawaii Cancer Center finds that the percentage varies among different ethnic groups, according to a University of Hawaii news release.

What You Need To Know

  • Top risk factors across demographics include diabetes, low socioeconomic status, physical inactivity, less education, low social contact, high blood pressure, and smoking
  • Results came from the Multiethnic Cohort Study involving 92,000 participants from diverse racial and ethnic groups that began in 1993
  • After a nine-year follow up (on average), researchers found approximately 16,500 participants had been diagnosed with Alzheimer’s or related dementia
  • According to the study, controllable risk factors (such as diabetes and physical inactivity) were highest among Latinos at 33%, Native Hawaiians at 29%, Black individuals at 28%, white individuals at 22%, and Japanese Americans at 14%

In the Jan. 17 issue of “Neurology,” the medical journal of the “American Academy of Neurology,” the study stressed the importance of addressing factors in each ethnic group to lower the risk of Alzheimer’s and related dementia.

“There is no cure for Alzheimer’s disease, so preventing or delaying this disease by reducing controllable risk factors is an urgent public health priority,” said study author and UH Cancer Center researcher Song-Yi Park, PhD, in the release.

The study showed what are the top risk factors across demographics:

  • Diabetes for Latinos, as well as less education and low socioeconomic status
  • Low socioeconomic status for Native Hawaiian people, as well as physical inactivity and less education
  • Low socioeconomic status for Blacks, as well as low social contact and high blood pressure
  • Low socioeconomic status for whites, in addition to smoking
  • Physical inactivity for Japanese Americans, in addition to diabetes

According to the release, the results came from the Multiethnic Cohort Study involving 92,000 participants from diverse racial and ethnic groups including Japanese American, white, Latino, Black and Native Hawaiian. An epidemiological study, the MEC has followed over 215,000 Hawaii and Los Angeles residents for health diseases since 1993.

Participants filled out detailed questionnaires that covered education, medical history, medications, physical activity, sleep patterns and dietary habits. Socioeconomic status was determined by residential addresses.

After a nine-year follow up (on average), researchers found approximately 16,500 participants had been diagnosed with Alzheimer’s or related dementia. They found higher percentages among Black (24%) and Native Hawaiian (14%) participants.

Because Native Hawaiians had been previously grouped with Asian Americans, the disparity among Native Hawaiians was not recognized, although studies have consistently shown Asian Americans have the lowest risk for Alzheimer’s or related dementia.

The study showed the combination of 12 controllable risk factors explained 23% of cases in men and women. After looking at “the strongest genetic risk factor, POE ε4,” researchers found 31% of cases could be credited to known risk factors.

Although percentages linked to controllable factors such as diabetes and physical inactivity were similar among male and females, variations emerged among the same factors between racial and ethnic groups.

According to the study, controllable risk factors were highest among Latinos at 33%, Native Hawaiians at 29%, Black individuals at 28%, white individuals at 22%, and Japanese Americans at 14%.

“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,” Park said.

“The study reveals the need for tailored interventions for various racial and ethnic groups, specific to more prevalent risk factors. It also highlights the importance of discovering other risk factors in racial and ethnic groups whose cases are not as well explained by known risk factors,” Park added.

Limitations to the study include insufficient data on risk factors such as hearing loss not treated with hearing aids, depression, traumatic brain injury or exposure to air pollution.

The National Cancer Institute and the National Institute on Aging at the National Institutes of Health funded the study.