As stroke severity increases, the risk of progressive cognitive decline and dementia substantially escalates, according to a national study led by Michigan Medicine researchers.
People with the most severe strokes had five times higher odds of developing dementia and showed cognitive decline equivalent to being more than two years older at baseline compared with people who did not have a stroke.
The results are published in JAMA Network Open .
“Stroke severity strongly affects thinking and memory after stroke,” said senior author Deborah A. Levine, M.D., M.P.H., professor of internal medicine and neurology at the University of Michigan Medical School.
“Our findings highlight the need to closely monitor cognition and aggressively treat dementia risk factors in all stroke survivors, especially those with severe strokes.”
The research team analyzed health care data from more than 42,000 American adults — including approximately 1,500 stroke survivors — who were followed for up to 30 years.
Dementia risk increased with stroke severity. Compared with people who did not have a stroke, dementia risk was about twice as high after a minor stroke, three times higher after a moderate stroke and five times higher after a severe stroke.
People without stroke showed some age-related cognitive decline over time. But stroke survivors had faster long-term declines in overall cognition, memory and executive function — and the declines were greater with more severe strokes.
On average, survivors of mild-to-moderate stroke declined as if they were 1.8 years older cognitively at baseline, and survivors of moderate-to-severe stroke declined as if they were 2.6 years older.
“Cognitive impairment is not limited to people with moderate or severe strokes; we also see it after mild strokes, so all survivors are at risk and should be monitored,” said Mellanie V. Springer, M.D., M.S., co-author and Thomas H. and Susan C. Brown Early Career Professor of Neurology at U-M Medical School.
“As stroke severity increases, structural and network damage also increase. This reduces the cognitive reserve and leaves the brain less able to compensate for the stroke itself, normal age-related decline and ongoing injury from vascular risk factors.”
Small vessel disease, neurodegeneration (including Alzheimer’s disease) and chronic inflammation may also contribute to cognitive decline and dementia after stroke.
Researchers say more studies are needed to better understand these mechanisms and to test treatments to prevent poststroke dementia and cognitive decline, including strategies that target blood pressure and glucose control.
Levine’s team previously reported that higher glucose levels after stroke are linked to faster poststroke cognitive decline .
“The best ways to prevent poststroke dementia and cognitive decline are to prevent first and second strokes,” Levine said.
“That means controlling blood pressure, glucose and cholesterol to optimal levels, and taking an anticoagulant when atrial fibrillation is present, as recommended.”
Additional authors: Emily M. Briceño, Ph.D., Bruno J. Giordani, Ph.D., Rodney A. Hayward, M.D., Jeremy Sussman, M.D., Rachael T. Whitney, Ph.D., Wen Ye, Ph.D., all of University of Michigan, Silvia Koton, Ph.D., R.N., of New York University Grossman School of Medicine, Tel Aviv University and Johns Hopkins Bloomberg School of Public Health, Alden L. Gorss, Ph.D., and Hang Wang, Ph.D., both of Johns Hopkins Bloomberg School of Public Health, Hugo J. Aparicio, M.D., and Alexa S. Beiser, Ph.D., of Boston University, Josef Coresh, M.D., Ph.D., of New York University Grossman School of Medicine, Mitchell S.V. Elkind, M.D., of the American Heart Association, Rebecca F. Gottesman, M.D., Ph.D., of the National Institute of Neurological Disorders and Stroke, Virginia J. Howard, Ph.D., and Ronald M. Lazar, Ph.D., both of the University of Alabama at Birmingham, Michelle C. Johansen, M.D., Ph.D., of the Johns Hopkins University School of Medicine, and Robert J. Stanton, M.D. of the University of Cincinnati.
Funding/disclosures: This work was funded by the National Institute on Aging of the National Institutes of Health (RF1AG068410)
The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
Paper cited:“ Ischemic Stroke Incidence and Severity and Poststroke Cognitive Decline and Incident Dementia,” JAMA Network Open . DOI: 10.1001/jamanetworkopen.2026.8900
JAMA Network Open
10.1001/jamanetworkopen.2026.8900
Observational study
People
“Ischemic Stroke Incidence and Severity and Poststroke Cognitive Decline and Incident Dementia
16-Apr-2026
This study was funded by grant RF1AG068410 from the NIA, NIH, US Department of Health and Human Services (DHHS). The Atherosclerosis Risk in Communities (ARIC) study is performed as a collaborative study supported by contracts 75N92022D00001, 75N92022D00002, 75N92022D00003, 75N92022D00004, and 75N92022D00005 from the National Heart, Lung, and Blood Institute (NHLBI). The ARIC Neurocognitive Study is supported by grants U01HL096812, U01HL096814, U01HL096899, U01HL096902, and U01HL096917 from NIH (NHLBI, NINDS, NIA, and National Institute on Deafness and Other Communication Disorders). The Reasons for Geographic and Racial Differences in Stroke (REGARDS) project is supported by cooperative agreement U01NS041588 cofunded by NINDS and NIA, NIH, DHHS. The Framingham Heart Study is supported by grant 75N92019D00031 from NHLBI, with additional support from grants HHSN268201500001, R01HL107385, and N01HC251952 from NHLBI and U19AG023122 from NIA, NIH. The content is solely the responsibility of the authors and does not necessarily represent the official views of NINDS or NIA.