U.S. Rate of Dementia Declining — But Beware of Growing Numbers, Scholars Say

The good news: the rate of older Americans with dementia is on the decline. The bad news: The number of Americans age 85 and older will roughly double in the next 20 years, so even with a decline in the rate of dementia among older adults, the number of people with dementia will likely increase substantially, according University of Michigan researcher Robert Schoeni, PhD.
 
The impact on both those with dementia and the people who care for them is significant. More than 45 million people worldwide have dementia. Its economic impact, including unpaid care provided by families, is estimated to be about $800 billion annually, said Schoeni, a professor at the University of Michigan’s Institute for Social Research, Gerald R. Ford School of Public Policy, and Economics Department.
 
Schoeni, along with Vicki Freedman, PhD, and Ken Langa, MD, PhD, have led the production of a new supplemental issue of The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences that examines trends in dementia across the U.S. The nine studies contained within provide new evidence on whether dementia trends have been more favorable, and reasons for those trends.
 
“The overall favorable trend seems to be linked to higher education levels among today’s older Americans,” said Freedman, a research professor of the University of Michigan Institute for Social Research. “But substantial gaps remain between more and less educated groups.”
 
The journal supplement — titled “Trends in the Prevalence and Incidence of Dementia: Causes, Disparities, and Projections for the Future” — stems from a May 2017 workshop funded by the National Institute on Aging that aimed to broaden the understanding of dementia trends, including a study that examines how education levels influence years expected to be lived with dementia.
 
The studies also look at the impact of cardiovascular disease on dementia. Reducing cardiovascular diseases and other chronic diseases is critical for the health of individuals and families, but because such advantages allow people to live to older ages when dementia is more common, the number of dementia cases may not decrease.
 
“By far the most powerful way to lower both the proportion and number of people with dementia is to develop prevention strategies and treatments that would directly delay the onset of dementia,” said Langa, a research professor of the University of Michigan Institute for Social Research, professor of Internal Medicine, and research scientist at the Veterans Affairs Ann Arbor Center for Clinical Management Research.
 
Together, the studies generated a number of cross-cutting themes. In addition to the overall decline in dementia prevalence, the supplement's studies show the following:

• Some groups of older adults in the U.S. are living fewer years with dementia.
• Racial and socioeconomic disparities in dementia are large and not diminishing.
• Rising levels of education partially account for the decline of dementia prevalence, but more research is needed to understand the role cardiovascular risk factors in trends of dementia.
• Reducing the incidence of diabetes and hypertension in midlife will increase the future number of cases of dementia because people will live longer. Therefore, postponing the onset of dementia directly is the most effective way to further reduce the size of the population living with dementia.

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The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences is a peer-reviewed publication of The Gerontological Society of America (GSA), the nation's oldest and largest interdisciplinary organization devoted to research, education, and practice in the field of aging. The principal mission of the Society — and its 5,500+ members — is to advance the study of aging and disseminate information among scientists, decision makers, and the general public. GSA’s structure also includes a policy institute, the National Academy on an Aging Society, and an educational unit, the Academy for Gerontology in Higher Education.