Does Vascular Risk in Middle Age Increase Dementia Incidence?

Vascular risk factors measured in midlife are associated with increased risk of dementia, according to a new study.

“In particular, both hypertension and prehypertension in midlife were associated with an increased risk for dementia when compared with people who had normal blood pressure,” said lead study author Rebecca Gottesman, MD, PhD, associate professor of neurology and epidemiology at Johns Hopkins University in Baltimore, MD. “In addition, midlife diabetes was associated with a nearly 2-fold increased risk of dementia. People who were smokers in midlife also had an increased risk of dementia.”
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Researchers recruited participants in the biracial Atherosclerosis Risk in Communities (ARIC) study from 4 US communities in 1987-1989, at ages 45-64, with 4 additional in-person visits, surveillance for hospitalizations, annual phone calls, and repeated cognitive evaluations over a 25-year period. In 2011-2013, investigators saw ARIC participants for the ARIC Neurocognitive Study (ARIC-NCS), and they underwent a detailed neurocognitive battery and informant interviews. Through adjudicated review, they defined dementia cases and identified additional dementia cases through the telephone interview for cognitive status or informant interview for those participants not attending ARIC-NCS; or by a prior dementia ICD-9 code during a hospitalization.

Of 15,744 participants in the cohort, researchers identified 1516 cases of dementia, of whom over one-third were black. They found risk of dementia highest in individuals of black race, with less than a high school education, older age, APOE ε4 carriage, and who, at ARIC baseline, had hypertension, diabetes, or were current smokers. APOE ε4 and smoking were each stronger risk factors for dementia in whites than in blacks.

“Although our data don’t definitively show that treating risk factors will actually prevent dementia, our data do suggest that treating and preventing these risk factors is a potential way to prevent later-life dementia,” Dr Gottesman said. “Primary care providers can help educate their patients that it is important to control risk factors, such as diabetes and hypertension, and to quit smoking.”

The researchers are conducting related studies to understand more about the mechanism for a vascular impact on dementia, using various types of neuroimaging, she said. They also will continue to see ARIC participants for follow up, so they can track further progression to dementia among those who were normal or had only mild cognitive impairment at earlier visits.

—Mike Bederka

Reference:

Gottesman RF, Albert M, Coker L, et al. Midlife vascular risk factors and incident dementia in the ARIC cohort. International Stroke Conference 2017, Houston, Texas. February 22, 2017.