Summary: Hypertension in young-to-mid life is associated with worse gait and cognitive problems during middle age.
High blood pressure, or hypertension, affects everything from your arteries to your kidneys, from eyesight to sexual function. Among older adults, high blood pressure is also associated with cognitive decline as a result of interrupted blood flow to the brain, as well as strokes, heart attacks and impaired mobility.
A new Northwestern University-Tel Aviv University study has revealed that subjects who experienced relatively high blood pressure during young adulthood also experienced significant declines in cognitive function and gait in midlife (approximately 56 years old). The study cohort included about 200 young adults with an average age of 24 at the beginning of the study.
The research was led by Prof. Farzaneh A. Sorond and Dr. Simin Mahinrad of Northwestern University’s Department of Neurology and Prof. Jeffrey Hausdorff of TAU’s Sackler Faculty of Medicine, TAU’s Sagol School of Neuroscience and Tel Aviv Medical Center’s Center for the Study of Movement, Cognition, and Mobility at the Neurological Institute. The study was published in the American Heart Association’s journal Circulation in March.
“We find that the deleterious effects of elevated blood pressure on brain structure and function begin in early adulthood. This demonstrates the need for preventive measures of high blood pressure even at this early age,” explains Prof. Hausdorff. “We know that poor gait and cognitive function among older adults are associated with and predict multiple adverse health outcomes like cognitive decline, dementia, falls and death. Our study shows that the time to treat high blood pressure and to minimize future changes in gait and cognition is much earlier — decades earlier — than previously thought.”
In addition, the study suggests that gait impairment may be an earlier hallmark of hypertensive brain injury than cognitive deficits.
For the study, the researchers assessed the blood pressure, gait and cognition of 191 participants from the Coronary Artery Risk Development in Young Adults study, a community-based cohort of young individuals followed over 30 years. In the last year of follow-up, gait was assessed using an instrumented gait mat; cognitive function was evaluated using neuropsychological tests; and the level of white matter intensity in the brain, a symptom of cardiovascular disease, was measured using MRIs. The impact of cumulative levels of high blood pressure was found to be independent of other vascular risk factors over the same 30-year period.
“Higher cumulative blood pressure was associated with slower walking speed, smaller step length and higher gait variability,” Prof. Hausdorff says. “Higher cumulative blood pressure was also associated with lower cognitive performance in the executive, memory and global domains.”
“Our takeaway is this: Even in young adults, blood pressure has significant implications, even at levels below the ‘hypertension’ threshold, and is important to assess and modify for future cognitive function and mobility,” Prof. Hausdorff concludes.
About this neuroscience research article
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Cumulative Blood Pressure Exposure During Young Adulthood and Mobility and Cognitive Function in Midlife
Background: High blood pressure (BP) is a known risk factor for mobility and cognitive impairment in older adults. This study tested the association of cumulative BP exposure from young adulthood to midlife with gait and cognitive function in midlife. Furthermore, we tested whether these associations were modified by cerebral white matter hyperintensity (WMH) burden.
Methods: We included 191 participants from the CARDIA study (Coronary Artery Risk Development in Young Adults), a community-based cohort of young individuals followed over 30 years. Cumulative BP was calculated as the area under the curve (mm Hg×years) from baseline up to year 30 examination. Gait and cognition were assessed at the year 30 examination. Cerebral WMH was available at year 30 in a subset of participants (n=144) who underwent magnetic resonance imaging. Multiple linear regression models were used to assess the association of cumulative BP exposure with gait and cognition. To test effect modification by WMH burden, participants were stratified at the median of WMH and tested for interaction.
Results: Higher cumulative systolic and diastolic BPs were associated with slower walking speed (both P=0.010), smaller step length (P=0.011 and 0.005, respectively), and higher gait variability (P=0.018 and 0.001, respectively). Higher cumulative systolic BP was associated with lower cognitive performance in the executive (P=0.021), memory (P=0.015), and global domains (P=0.010), and higher cumulative diastolic BP was associated with lower cognitive performance in the memory domain (P=0.012). All associations were independent of socio-demographics and vascular risk factors (body mass index, smoking, diabetes mellitus and total cholesterol). The association between cumulative BP and gait was moderated by WMH burden (interaction P<0.05). However, the relation between cumulative BP and cognitive function was not different based on the WMH burden (interaction P>0.05).
Conclusions: Exposure to higher BP levels from young to midlife is associated with worse gait and cognitive performance in midlife. Furthermore, WMH moderates the association of cumulative BP exposure with gait, but not with cognitive function in midlife. The mechanisms underpinning the impact of BP exposure on brain structure and function must be investigated in longitudinal studies using a life course approach.