Prehypertension in Midlife Ups Later Dementia Risk  

Megan Brooks

August 10, 2017

A new study provides more evidence that midlife vascular risk factors, such as hypertension, diabetes, and smoking, increase the risk for dementia in later life — and adds new data showing that prehypertension is also an important risk factor.

The study also suggests that the association between diabetes and dementia is "much larger than we expected; the risk associated with midlife diabetes is almost as high as the risk associated with having an ε4 copy of the APOE gene, which is the strongest known genetic risk factor for Alzheimer's disease," first author, Rebecca Gottesman, MD, PhD, professor of neurology and epidemiology at Johns Hopkins University, Baltimore, Maryland, told Medscape Medical News.

The take-home message for clinicians is clear, said Dr Gottesman. "Evaluate vascular risk in middle age. This is probably the window during which we might actually be able to reduce risk of dementia."

The study was published online August 7 in JAMA Neurology.

ARIC Cohort

The researchers assessed vascular risk factors at baseline, between 1987 and 1989, and at regular intervals over roughly the next 24 years in 15,744 participants in the biracial Atherosclerosis Risk in Communities (ARIC) cohort (27% black, 73% white). Participants were aged 44 to 66 years at baseline.

At the 2011–2013 assessment, 1516 total cases of dementia were identified.

Black race, older age, lower educational attainment, and APOE ε4 genotype were associated with increased risk for dementia, as were midlife smoking, diabetes, prehypertension, and hypertension. The risk for dementia with diabetes was nearly as high as that for APOE ε4 genotype.

Table. Risk for Later-Life Dementia by Midlife Factors

Risk Factor Hazard Ratio for Dementia (95% Confidence Interval)
Black race 1.36 (1.21 - 1.54)
Older age 8.06 (6.69 - 9.72)
Less than high school education 1.61 (1.28 - 2.03)
APOE ε4 genotype 1.98 (1.78 - 2.21)
Smoking 1.41 (1.23 - 1.61)
Diabetes 1.77 (1.53 - 2.04)
Prehypertension 1.31 (1.14 - 1.51)
Hypertension 1.39 (1.22 - 1.59)

Prehypertension: Get the Message Out

Asked to comment, Richard Isaacson, MD, director at the Alzheimer's Prevention Center at Weill Cornell Medicine and New York-Presbyterian in New York City, told Medscape Medical News: "I've been using the words 'Alzheimer's' and 'prevention' in the same sentence for a while now. This new study supports a number of other studies demonstrating that there is something that a person can potentially do that is safe and somewhat evidence-based to reduce their risk of dementia."

The novel finding here, he said, is that prehypertension in midlife is associated with dementia later on. "I hope this message gets out to people in the preventative medicine sphere. There are multiple points of risk and intervening in as many points of risk as possible is going to be the way to make progress," said Dr Isaacson.

As previously reported by Medscape Medical News, a study published last month in The Lancet found that more than one third of global dementia cases may be preventable by addressing nine lifestyle factors that affect an individual's risk: education, hearing loss, hypertension, obesity, smoking, depression, physical inactivity, social isolation, and diabetes.

"I buy that," said Dr Isaacson. "You can't prevent Alzheimer's in everybody, but from a practical clinical perspective, there are multiple things we can do to help prevent dementia in our patients."

The study had no commercial funding. Dr Gottesman reports serving as associate editor for Neurology. Disclosures for her coauthors are in the paper. Dr Isaacson has disclosed no relevant financial relationships.

JAMA Neurol. Published online August 7, 2017. Abstract

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