(HealthDay News) — Known risk factors account for a considerable proportion of Alzheimer’s disease and related dementia (ADRD) cases, with unequal distribution across race and ethnic groups, according to a study published online Jan. 17 in Neurology.

Using data from the Multiethnic Cohort Study participants, Song-Yi Park, PhD, from the University of Hawaii at Manoa in Honolulu, and colleagues examined the race- and ethnic-specific population-attributable fraction (PAF) of late-onset ADRD based on the prevalence of risk factors.

A total of 16,507 incident ADRD cases were identified from Medicare claims among 91,881 participants. The researchers found that the PAF for nongenetic factors combined was similar in men and women (24.0 and 22.8%, respectively), but varied for Japanese American, White, African American, Native Hawaiian, and Latino groups (14.2, 21.9, 27.8, 29.3 and 33.3%, respectively). When accounting for the competing risk for death, the combined PAF was attenuated in both men and women (10.4 and 13.9%, respectively) and across racial and ethnic groups (4.7 to 25.5%). The combined PAF also differed for age at diagnosis (43.2, 32.4 and 11.3% for 65 to 74 years, 75 to 84 years, and 85 years and older, respectively) and for ADRD subtypes, with a higher PAF for vascular or unspecified ADRD than for AD or Lewy body dementia. A PAF of 11.8% was associated with APOE ε4, which accounted for 30.6% of ADRD in combination with nongenetic risk factors.

“Our findings call for interventions in the racial and ethnic groups with a large proportion of preventable cases and individually modifiable risk factor profiles,” the authors write.

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