Disease-preventing or disease-modifying treatments do not exist for Alzheimer disease or other dementias. Adults may be unaware of strategies to reduce their risk1 and resort to marketed but ineffective options, such as ginkgo biloba or vitamin E. While these so-called treatments are relatively inexpensive, new preventive therapies may not be. Thus, individuals overestimating their risk of developing dementia could lead to inappropriate use and excessive costs.2 This analysis explores how adults aged 50 to 64 years estimate their lifetime risk of dementia and the risk-reducing strategies they pursue.