Lifetime Dementia Risk Highest Among Women, Black Adults, APOE ε4 Carriers

Lifetime risk for dementia is higher among women, Black adults, and apolipoprotein E4 (APOE ε4) allele carriers, according to results of a study published in Nature Medicine.

Using data from a community-based prospective cohort study, researchers evaluated adults for incident dementia and projected the number of new dementia diagnoses over the next 4 decades. A total of 15,043 adults were included in the final analysis, among whom 55.1% were women, 72.8% were White, 28.1% carried 1 copy of APOE ε4, and 2.7% carried 2 copies of APOE ε4.

During a median follow-up of 23 (IQR, 16-27) years, the researchers identified 3252 incident cases of dementia. Diagnoses were made through phone interview (49%), review of medical or death records (27%), or at cognitive testing follow-up visits (24%).

The researchers estimated a 42% (95% CI, 41-43) lifetime risk of developing dementia between the ages of 55 and 95 years. The cumulative incidence from age 55 to 75 years remained low (3.9%) and increased substantially thereafter. Lifetime risk estimates were higher among women than men, at 48% (95% CI, 46-50) vs 35% (95% CI, 33-36). Risk was also greater in Black adults than White adults, at 44% (95% CI, 41-46) vs 41% (95% CI, 40-43). Additionally, those carrying 2 or 1 copy of the APOE ε4 allele had risks of 59% (95% CI, 53-65) and 48% [95% CI, 45-50], respectively, while those without APOE ε4 had a risk of 39% (95% CI, 37-40).

Median age at dementia diagnosis was 81 (IQR, 77-86) years. However, dementia occurred earlier among Black adults than White adults. The median age at diagnosis was 79 (IQR, 75-84) years for Black adults and 81 (IQR, 78-86) years for White adults. Dementia diagnosis also occurred earlier for those carrying 2 or 1 copy of APOE ε4 than for those without the allele. The median age at diagnosis was 79 (IQR, 75-82) years for those with 2 copies, 81 (IQR, 77-85) years for those with 1 copy, and 82 (IQR, 77-86) years for those without APOE ε4.

Applying these findings to US Census projection data, the researchers estimated that incident dementia cases will increase from approximately 514,000 cases in 2020 to approximately 1 million cases in 2060.

Limitations include the potential for dementia misclassification and limited population diversity.

The study authors concluded, “Policies that enhance prevention and healthy aging are urgent public health priorities for reducing the substantial and growing burden of dementia.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.