Dementia insurance, a private insurance product covering the first diagnosis of dementia of the insured, may be economical for asymptomatic individuals who are aware of their own high genetic risk of developing Alzheimer's disease (AD) in advance. This is a retrospective study conducted based on National Alzheimer's Coordinating Center (NACC) data including cognitively unimpaired individuals, aiming to simulate income and expenses of dementia insurance for the insured perspectives. Loss ratio (= total benefits gained / total premium paid) was calculated by APOE-ε4 subgroup as a measure of cost-effectiveness, applying the premium rates of actual dementia insurance products being sold in Japan. As a result, for up to 18 years of longitudinal follow-up, the estimated cost-effectiveness improved over the longer observation periods. In individuals in their 60s or older at baseline, the cost-effectiveness was best in the APOE-ε4 homozygotes, followed by heterozygotes, and ε4-negative individuals. The dementia insurance for ε4-homozygotes for observation periods ≥ 10 years in this age group was approximately 3 to 4 times more economical than for ε4-negative individuals. Although actively pursuing APOE testing for asymptomatic individuals may not be currently recommended due to the concern of adverse selection in the insurance and the absence of available disease-modifying therapy approved for the preclinical stage of AD, our study may provide an important basis for further investigating the advantages and limitations of dementia insurance for asymptomatic individuals with pathogenic or high-risk genes.

The authors have declared no competing interest.

This study was supported by AMED Grant Numbers JP23dk0207048 (TI) and JP24dk0207054 (YN), and JSPS KAKENHI Grant Number JP24K10653 (KS). The sponsors had no role in the design and conduct of the study; collection, analysis, and interpretation of data; preparation of the manuscript; or review or approval of the manuscript.

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The study used ONLY openly available human data that were originally located at National Alzheimer's Coordinating Center (NACC) (https://naccdata.org).

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All data produced are available online at National Alzheimer's Coordinating Center (NACC) (https://naccdata.org).