With Americans living longer and the large baby boom generation reaching ages 65 and beyond, the sheer numbers of people with conditions of old age—including Alzheimer’s disease and other dementias—are expected to rise dramatically in coming years. But there is some potentially good news: The share of the population with dementia may have fallen over the past 25 years—likely the result of better brain health related to more schooling and aggressive treatment of high blood pressure and diabetes.

This report explores the evidence of a decline in dementia and the trends that may shape the future prevalence of this debilitating condition—focusing on recent work by researchers supported by the National Institute on Aging (NIA).

It describes what we know (and do not know) about dementia patterns, examining known risk factors and vulnerable groups. This research can guide policymakers and public health professionals as they plan for an aging population and design strategies to address health and lifestyle factors related to dementia risk.