Hypertension, or high blood pressure, impacts more than 30% of adults worldwide. Yet, over half of the individuals with high blood pressure are unaware they have the condition.
Chronically elevated blood pressure is a primary risk factor for coronary heart disease, stroke, kidney disease, and dementia.However, little is known about how high blood pressure harms the brain and in what specific brain regions this damage occurs.In a new study using observational and genetic data from a cohort of more than 30,000 participants from the U.K. Biobank, an international team of researchers has found what areas in the brain are impacted by high blood pressure. Moreover, these are the same brain areas responsible for cognitive functions, such as memory and thinking skills."By using this combination of imaging, genetic and observational approaches, we have identified specific parts of the brain that are affected by increases in blood pressure, including areas called the putamen and specific white matter regions," says lead researcher Tomasz Guzik, Professor of Cardiovascular Medicine at the University of Edinburgh and Jagiellonian University Medical College in Krakow, Poland, in a news release."We thought these areas might be where high blood pressure affects cognitive function, such as memory loss, thinking skills, and dementia," he continues. "When we checked our findings by studying a group of patients in Italy who had high blood pressure, we found that the parts of the brain we had identified were indeed affected."Specifically, the team identified hypertension-related changes in nine brain regions. These include:The putamen: A structure found in the base of the front of the brain responsible for regulating movement and learning.The anterior corona radiata, anterior thalamic radiation, and anterior limb of the internal capsule: Areas of white matter that support signaling between different parts of the brain.The anterior thalamic radiation: A region involved in executive functions, including task planning.The other two regions researchers identified are responsible for decision-making and managing emotions.The changes they found included reduced brain volume and surface area, changes to connections between brain regions, and changes in brain activity.Moreover, the team discovered that diastolic blood pressure (DBP) and systolic blood pressure (SBP) have distinct effects. For example, DBP alone does not predict cognitive function decline. Instead, it’s protective against cognitive decline when adjusted for systolic blood pressure (SBP).Co-author Professor Joanna Wardlaw, Head of Neuroimaging Sciences at the University of Edinburgh, concludes, "This study shows that specific brain regions are at particularly high risk of blood pressure damage, which may help to identify people at risk of cognitive decline in the earliest stages, and potentially to target therapies more effectively in future."