The LifeAfter90 study, conducted by researchers at UC Davis Health and Kaiser Permanente, provides new insights into dementia risk among individuals aged 90 and older. The study, published in The Lancet Healthy Longevity, reveals that dementia disparities observed earlier in life persist into advanced old age. Women aged 90 and older had approximately twice the dementia risk of men, and black participants faced a 75% higher risk compared to Asian participants. These findings underscore the continuation of sex- and race-based dementia risk differentials into the ninth and tenth decades of life.
The research also examined the role of the APOE gene, which is strongly associated with Alzheimer’s disease. The protective effect of the APOE2 variant remained significant even beyond age 90, with carriers exhibiting a 60% lower risk of dementia. Conversely, the APOE4 variant, known to increase Alzheimer’s risk, did not substantially raise dementia incidence across the entire study population. However, APOE4 was associated with higher dementia risk among men and approximately doubled the risk among black participants. The study highlights the differential impact of APOE genotypes on dementia risk by sex and race/ethnicity in individuals aged 90 and older. [Source: https://www.sciencedaily.com/releases/2026/08/260829235953.htm]