Dementia Risk Persists Past Age 90

Numerous individuals believe that reaching age 90 without dementia signifies they have avoided the condition. Recent research suggests otherwise. Researchers from the University of California, Davis Health and Kaiser Permanente examined over 800 adults aged 90 and older in the ongoing LifeAfter90 study. The study found that the risk of dementia continues into advanced age with differences noted by sex, race, ethnicity, and genetics. The findings were published in The Lancet Healthy Longevity.

Study Insights

This study is among the first to explore dementia risk in a diverse group of individuals over 90 who did not show signs of dementia at the start. Rachel Whitmer, a UC Davis Health professor and senior author of the study, emphasized the lack of information on this age group. Understanding who remains most affected by dementia after 90 and how the APOE gene factors in is crucial.

Participants, members of Kaiser Permanente, underwent assessments every six months to monitor cognitive health changes. With many having long histories in the health system, researchers accessed records dating back decades. This information provided valuable insights into cognitive health trajectories.

Key Findings

• Women had double the risk of developing dementia compared to men, even past age 90.
• Racial and ethnic disparities persisted, with Black participants having a 75% higher risk than Asian participants.
• Overall, Black and Hispanic individuals experienced higher dementia incidence compared to White and Asian counterparts.

Hilary Colbeth, a UC Davis postdoctoral scholar and first author, noted that these racial and ethnic disparities persist into the 10th decade of life.

Examining APOE

Researchers analyzed the APOE gene, associated with Alzheimer’s risk. The APOE2 variant provided protection, reducing dementia risk by about 60%. APOE4 did not broadly increase dementia incidence, but it substantially raised risk in Black participants and was linked to elevated risk among men. This gene’s impact on mortality among those with and without dementia after age 90 is now closely examined.

Interestingly, some participants remained cognitively healthy despite risk factors such as APOE4, indicating potential protective factors at play. Understanding these factors is a significant area of interest.

Implications of the Findings

Lisa George, a New York City Psychiatry NP uninvolved in the research, stated the findings challenge a misconception about aging. Though reaching 90 with ‘intact cognition’ offers encouragement, it does not eliminate dementia risk. George highlighted the complexity of dementia in the ‘oldest old’ due to simultaneous brain changes.

Memory complaints in very old adults should not be automatically interpreted as dementia. Depression, anxiety, poor sleep, and medication side effects can mimic dementia symptoms, according to George.

The study’s authors assert these findings can help clinicians identify which groups remain at higher risk in advanced age. Doctors must recognize that hygiene and preventive measures are crucial, even for those past 90 from high-risk groups.

Future of Dementia Research

The findings suggest that dementia risk does not level off at age 90, prompting questions about the influence of aging, genetics, and health disparities on cognitive decline in this age group. Research is steering toward early detection and prevention. Emerging blood-based biomarker tests could identify Alzheimer’s risk years ahead of symptoms, enabling earlier interventions.

Results from studies like LifeAfter90 could shape future screening, treatment, and prevention strategies for the aging population.