Hypertensive Pregnancy Disorder May Be Detrimental to Cognitive Function, Brain Volume

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Women who had high blood pressure while pregnant demonstrated later cognitive impairment and smaller brain volume compared with women who had normotensive pregnancies.
Women who had high blood pressure while pregnant demonstrated later cognitive impairment and smaller brain volume compared with women who had normotensive pregnancies.

VANCOUVER, British Columbia — Long-term outcomes suggest that women who experienced hypertension during pregnancy demonstrate worse cognitive function and smaller brain volume when compared with women who were normotensive when pregnant.

“These results suggest that [hypertensive pregnancy disorders (HPDs)] are independent predictors of impaired brain structure and cognitive function, and may identify those women at greater risk of future dementia,” study investigator Michelle Mielke, PhD, of the Mayo Clinic in Rochester, Minnesota, told Neurology Advisor.

The aim of the study, which was presented at the 2016 annual meeting of the American Academy of Neurology (AAN), was to evaluate the relationship between HPDs and cognitive performance and brain magnetic resonance imaging (MRI) findings decades later in a multiethnic sample of women.

“Although [cardiovascular disease (CVD)] is a well-recognized risk factor for cognitive decline and dementia, there is a dearth of information as to the effects of HPD on brain structure and cognitive function, and whether such an association might be solely mediated by CVD,” Dr Mielke said. “Previous studies reported associations between HPD and subjective cognitive complaints or brain [white matter hyperintensities] on MRI.”

Dr Mielke noted, however, that these studies had small sample sizes and only assessed brain structure and cognitive function less than 10 years after HPD.

“The longer-term effects of HPD on brain structure and cognitive function remain unknown, but [are] important to examine to determine whether HPD is a risk factor for dementia,” she said.

For the study, Dr Mielke and colleagues enrolled 1167 women (mean age, 61 years) who participated in the Family Blood Pressure Project Genetic Epidemiology Network of Arteriopathy (GENOA) study. The researchers performed a neurocognitive battery as part of the ancillary Genetics of Microangiopathic Brain Injury study.

In all, 972 women underwent MRI assessment that measured brain, ventricular, and white matter lesion volumes.

Researchers determined a history of HPD via a self-report with a validated questionnaire. In addition, they utilized linear models fit with generalized estimating equations to determine the association between HPDs and cognition after adjusting for age, race, education, body mass index, smoking, current hypertension, and family history of hypertension, and they used regression models for the brain MRI outcomes adjusted for total intracranial volume.

According to results of the study, women with a history of HPD did worse on all processing speed measures, including digit symbol substitution test (mean score, 41.2 vs 43.4; P=.005); Trail Making Test Part A (mean seconds, 45.1 vs 42.2; P=.035), and the Stroop effect test (mean score, 173.9 vs 181; P=.002).

Furthermore, compared with women who had a history of normotensive pregnancies, those with a history of hypertensive pregnancies had smaller brain volume (286 vs 297; P=.023).

“Our study suggests that women with histories of HPD have greater brain atrophy decades after their pregnancies compared with women who had normotensive pregnancies. There was also a trend for white matter lesions [in this group],” Dr Mielke said. “Further, our results indicate that cognitive impairment occurs in the setting of structural brain changes for women with a mean age of 61 years. Thus, women with histories of HPD may need to be closely monitored for signs and symptoms of cognitive decline, and their modifiable risk factors need to be treated adequately.”

Dr Mielke added that HPDs are increasingly recognized as a risk factor for CVD and, therefore, cognitive decline and brain changes may be mediated solely by subsequent diagnoses of hypertension or CVD.

“Alternatively, HPDs may represent a risk factor that is independent of the effects of CVD,” she said.

Click here for more coverage from the 68th Annual Meeting of the American Academy of Neurology, April 15-21, 2016, in Vancouver, British Columbia, Canada.

Reference

Mielke M, Milic N, Weissgerber TL, et al.. Cognition and brain atrophy decades after hypertensive pregnancy disorders. Presented at: The 68th Annual Meeting of the American Academy of Neurology; April 15-21, 2016; Vancouver, British Columbia, Canada. Abstract P1.089

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