Even after age 90, dementia risk doesn’t disappear—it remains strongly influenced by genetics, sex, and race, according to a new study. A remarkable group of resilient brains may hold keys to lifelong cognitive protection.
The Research
Researchers from UC Davis Health and Kaiser Permanente followed over 800 people aged 90 and older with no initial signs of dementia, tracking their cognitive health every six months. The LifeAfter90 study, published in The Lancet Healthy Longevity, is the first to examine dementia after 90 in a diverse cohort.
Results show women in their 90s had about twice the dementia risk of men. Black participants faced a 75% higher risk than Asian participants, and both Black and Hispanic participants had significantly higher rates than white and Asian groups.
Genetics also mattered. Carrying APOE2, a protective variant, lowered dementia risk by 60%. APOE4, the well-known risk gene, didn’t increase risk across the whole group but doubled dementia risk among men and among Black participants.
Surprisingly, some participants who had risk factors like hypertension and high cholesterol in midlife remained cognitively sharp into their 90s. “We need to understand who is most affected and how the brain can resist dementia,” said Rachel Whitmer, senior author.
Why It Matters
With more people living past 90, knowing how dementia risk evolves is crucial. This study shows that disparities seen earlier in life persist into extreme old age—so research and prevention must include the oldest old.
The resilient group is especially intriguing. If scientists can identify what protects them, they might find new strategies to help everyone age with a healthier brain.
What You Can Do
While you can’t change your genes or sex, you can take steps to support brain health at any age. Stay physically active, eat a heart-healthy diet, keep your mind stimulated, and manage blood pressure and cholesterol. Even in your 90s, it’s not too late to benefit from healthy habits.
Source: ScienceDaily Mind & Brain
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