Health

Dementia risk persists after age 90, heavily influenced by sex and demographics, study finds

An analysis of the LifeAfter90 study reveals that women, Black, and Hispanic individuals face higher rates of cognitive decline in extreme old age.

Updated Sep 1, 2026 · 13:21 UTC1 reports

The short version

A study of over 800 participants aged 90 and older found that dementia risk remains active in extreme old age rather than fading away.
Researchers identified significant disparities, showing that women face double the risk of men, and Black participants face a 75% higher risk than Asian participants.
The protective APOE2 gene variant was found to lower dementia risk by 60% even after age 90.

Researchers at UC Davis Health and Kaiser Permanente analyzed data from the LifeAfter90 prospective cohort study, tracking more than 800 participants with a median age of 92.[ScienceDaily]
Women aged 90 and older had approximately twice the risk of developing dementia compared to men of the same age group.[ScienceDaily]
Black and Hispanic participants experienced significantly higher dementia incidence rates than white and Asian participants, with Black participants facing a 75% higher risk than Asian participants.[ScienceDaily]
The APOE2 gene variant continued to offer protection past age 90, reducing dementia risk by 60%.[ScienceDaily]
The APOE4 risk variant did not substantially increase overall dementia incidence across the entire study population, but it did double the risk among Black participants and was associated with a higher risk among men.[ScienceDaily]

It remains unknown why some participants stayed cognitively healthy despite carrying the APOE4 risk gene or having midlife risk factors like high cholesterol and hypertension.[ScienceDaily]