Lifetime risk of incident dementia and incident mild cognitive impairment in older adults

Lifetime risk (cumulative incidence) of dementia and mild cognitive impairment (MCI) was estimated from ages 55 to 105 using nonparametric cumulative incidence models accounting for competing risk of death and left truncation. The estimated lifetime risk was 43% for incident dementia and 62% for MCI, with risk rising steeply after age 75 and appearing to level off at the oldest ages. Women and Black participants showed higher lifetime risks, partly reflecting mortality and selective survival dynamics. Exploratory analyses suggested elevated risks among Latino participants and those with a history of stroke. These findings extend lifetime risk estimation beyond age 90 and highlight the need for equitable, culturally informed dementia prevention and monitoring strategies.