A new study has found that having high blood pressure is linked to worse brain health in later life, especially for men. The study, published in JAMA Network Open, compared brain scans of older adults who had high blood pressure in their 30s to those who had normal blood pressure and found that the high blood pressure group had lower regional brain volumes and worse white matter integrity, both of which are linked to dementia.
“We were interested in the topic because there are very few treatment options for dementia. Identifying modifiable risk factors, like hypertension, are important for developing intervention strategies that might be able to prevent or delay dementia onset,” said study author Kristen M. George, an assistant professor of epidemiology at UC Davis School of Medicine.
The researchers used data from two harmonized longitudinal cohorts, the Study of Healthy Aging in African Americans (STAR) and the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study, to investigate the association between blood pressure in early adulthood and late-life neuroimaging biomarkers of neurodegeneration and white matter integrity.
The study participants were racially and ethnically diverse adults who received health assessments between June 1, 1964, and March 31, 1985, and underwent magnetic resonance imaging (MRI) between June 1, 2017, and March 1, 2022. The final analytic sample consisted of 427 participants who had complete data on early adulthood hypertension status and blood pressure (BP) change and late-life neuroimaging biomarkers.
The primary exposure of interest was hypertension, which was defined using the American Heart Association/American College of Cardiology guidelines as systolic BP of 130 mm Hg or higher, diastolic BP of 80 mm Hg or higher, or self-report of antihypertensive or heart medication use. The researchers assessed hypertension and BP at two time points in early adulthood (ages 30-40 years) and measured regional brain volumes and white matter integrity using MRI in late-life.
Participants who had hypertension in early adulthood or transitioned to hypertension tended to have significantly smaller average cerebral volume, which refers to the total volume of the brain. They also had smaller cerebral gray matter volume, frontal cortex volume, and parietal cortex volume. These areas of the brain are important for various cognitive processes like attention, memory, and decision-making, as well as for sensory processing and spatial awareness.
Additionally, the researchers found that people who had high blood pressure in early adulthood had smaller brain volumes in the hippocampus, which is a region involved in memory formation. They also had lower FA (fractional anisotropy), which is an indicator of decreased brain integrity.
“This study indicates that high blood pressure as early as young adulthood (30-40s) is bad for brain health in late life,” George told PsyPost. “These findings emphasize the importance of maintaining healthy blood pressure starting in early adulthood, in order to maintain brain health into late life.”
Interestingly, the study found that there were sex differences in the association between high blood pressure and brain volumes. In men, there was a stronger association between high blood pressure in early adulthood and lower volumes of the cerebral gray matter and frontal cortex, as well as lower FA.
Finally, the researchers found that even small increases in blood pressure were associated with lower brain volumes in specific areas. A 5-mm Hg increase in systolic blood pressure was associated with lower temporal cortex volume, which is involved in auditory processing and language comprehension.
A 5-mm Hg increase in diastolic blood pressure was associated with lower parietal cortex volume, which is involved in sensory processing and spatial awareness. These effects also differed between men and women.
“We found that the detrimental effects of high blood pressure were stronger in men than women for some brain regions,” George told PsyPost. “However, I found it striking that, regardless of gender, elevated blood pressure in young adulthood was bad for the brain in late life.”
The researchers controlled for potential confounders that might influence the association between hypertension status and late-life neuroimaging biomarkers. These included race and ethnicity, age at imaging and first major health checkup, sex, and educational attainment. But like any study, the new research includes limitations.
“We did not have information on anti-hypertensive medication use and only had blood pressure measurements from two time points in early adulthood,” George explained. “More work is needed to understand how consistent treatment for high blood pressure from young adulthood through late life might modify these results in individuals with hypertension.”
The study, “Association of Early Adulthood Hypertension and Blood Pressure Change With Late-Life Neuroimaging Biomarkers“, was authored by Kristen M. George, Pauline Maillard, Paola Gilsanz, Evan Fletcher, Rachel L. Peterson, Joseph Fong, Elizabeth Rose Mayeda, Da nM. Mungas, Lisa L. Barnes, Maria Glymour, Charles DeCarli, and Rachel A. Whitmer.