Study Finds Dementia Risk Persists Past 90, Varies by Sex, Race and Genes

The LifeAfter90 study, a partnership between UC Davis Health and Kaiser Permanente, has monitored a diverse group of adults aged 90 and above since 2018 to assess dementia incidence. Using semi-annual evaluations and extensive medical records, researchers analyzed over 800 participants with a median age of 92. Findings published in The Lancet Healthy Longevity indicate that women over 90 have about twice the dementia risk of men, and Black individuals experience a 75% higher risk compared with Asian participants, while Hispanic participants also show elevated rates.

Genetic analysis confirmed that the APOE2 variant remains strongly protective, cutting risk by roughly 60%, whereas APOE4’s impact varies, raising risk for men and nearly doubling it for Black participants. Notably, a subset of participants with prior hypertension or high cholesterol, and even some APOE4 carriers, remained cognitively intact, suggesting unknown protective factors. The study underscores the need for clinicians to consider demographic and genetic risk profiles when advising older patients. Funding was provided by the National Institute on Aging of the NIH.