Midlife Hypertension Linked to Steeper Cognitive Decline

Midlife Hypertension Linked to Steeper Cognitive Decline

Having hypertension or elevated systolic blood pressure (SBP) in midlife, but not in late-life, was associated with greater cognitive decline, new research suggests.

hypertension brain

The results of the new study, conducted by investigators at Johns Hopkins University School of Medicine in Baltimore, Maryland, adds further evidence supporting an association between elevated blood pressure in middle age and cognitive change over time.

“Midlife hypertension, by several definitions, and elevated midlife but not late-life SBP were associated with more cognitive decline during the 20-year ARIC [Atherosclerosis Risk in Communities] Study. Greater linear decline is found with higher midlife BP in white than in African-American participants,” the authors, led by Rebecca Gottesman, MD, PhD, write.

The study was published online August 4 in JAMA Neurology.

Hypertension and Cognition Testing Results

For the study, researchers analyzed data on 13,476 middle-aged (48 to 67 years) white and African Americans who were participants in the ARIC study, a prospective epidemiologic study carried out in 4 US communities.

Study participants underwent cognitive tests at visit 2 (1990 to 1992), visit 4 (1996 to 1998), and visit 5 (2011 to 2013). They completed 3 cognitive tests: the Delayed Word Recall Test, which assesses verbal learning and short-term memory; the Digit Symbol Substitution Test (DSST), which evaluates executive function and processing speed; and the Word Fluency Test (WFT), which measures executive function and expressive language.

Researchers calculated mean scores for each cognitive test and developed a global cognitive score.

They also rigorously measured SBP and diastolic blood pressure (DBP). They defined blood pressure as normal (SBP/DBP <120/80 mmHg and no use of antihypertensive agents), prehypertension (SBP 120 to 139 mmHg or DBP 80 to 89 mmHg), or hypertension (SBP ?140 mmHg, DBP ? 90 mmHg or antihypertensive use).

Researchers evaluated the relationship of midlife hypertension with 20-year cognitive change. Compared with those who did not have hypertension, those with hypertension had steeper global cognitive decline.

There were similar associations for the WFT and the DSST. “As hypothesized, hypertension was most consistently associated with the DSST score, the test reflecting domains most typically affected by vascular disease,” the authors note.

Prehypertension was also associated with DSST decline. Those with prehypertension had cognitive decline of 4.8% greater than those with normal blood pressure, and those with hypertension had a decline of 6.5% greater.

Participants with treated hypertension had an intermediate decline of cognition compared with those with prehypertension and untreated hypertension.

Continuous SBP measures were associated with global cognitive decline in white but not African American participants.

“In contrast to studies supporting a J-shaped curve from midlife BP (with worse outcomes at very low BP for cognition, cardiovascular disease, stroke and brain white matter hyperintensities in older persons), we found a nearly continuous effect of midlife SBP with steeper cognitive decline as BP increased in whites only,” the investigators write.

The authors concluded that in the elderly, higher BP may be less detrimental.

On the basis of sensitivity analyses, the authors said that their estimates of the relationship between blood pressure and cognitive decline may be conservative.

Hypertension Link to Cognitive Decline Not Yet Conclusive

In an accompanying editorial, Philip B. Gorelick, MD, translational science and molecular medicine, Michigan State University College of Human Medicine in Grand Rapids, said the study results are important but are “not those of a randomized clinical trial representing a higher-level evidence-based medical decision-making source” and so may not provide conclusive advice for physicians on how to manage BP to prevent cognitive decline.

Dr. Gorelick pointed out that the usefulness of BP lowering for preservation of cognition is not well established in patients older than 80 years.

“In fact, relatively higher BP in the very old has been suggested to be associated with better cognitive outcomes. Furthermore, once cognitive impairment is present, one may need to relax BP control; however, this remains to be proven by additional study,” he notes.

Until there is further evidence, Dr. Gorelick recommends practitioners balance the benefit of BP lowering on cardiovascular disease risk reduction with the possible risk or benefit to cognition on a “case by case” basis.

Because cardiovascular risk factors are linked to vascular cognitive impairment and Alzheimer’s disease (AD), the office benchmark for measuring BP — the brachial cuff — may be “too simplistic,” said Dr. Gorelick. “We may need to expand our armamentarium for measuring the influence of BP on cognition to techniques such as central BP, pulse wave velocity, and arterial stiffness and take into account the role of BP variability.”

JAMA Neurol. Published online August 4, 2014.