According to a new study published in the European Heart Journal, those who have high blood pressure during midlife could be more at risk for brain damage later in life. Not all people with high blood pressure will develop these changes, but the study was able to show that more than 50% of patients over the age of 65 and most people over the age of 80, even without high blood pressure, will show specific signs of brain damage. Those with high blood pressure are more likely to have a more severe condition.
The study included findings from a study of 37,041 participants who were enrolled in the UK Biobank. This Biobank is a large group of people aged between 40 and 69 who agreed to have their medical information available for research, including MRI brain scans. Their data was collected at the start of enrollment between 2006 and 2010. Follow-up data were acquired between 2014 and 2019.
Researchers analyzed the MRI brain scans for any damage in the brain called white matter hyperintensities (WMH). These areas show up on MRI scans as bright regions that indicate damage to the brain’s small blood vessels that are known to increase with age and blood pressure. WMH has previously been associated with an increased risk of stroke, depression, dementia, physical disabilities, and cognitive decline.
White Matter in the Brain
“To compare the volume of white matter hyperintensities between people and to adjust the analysis for the fact that people’s brains vary slightly in size, we divided the volume of WMH by the total volume of white matter in the brain. In that way, we could analyze the WMH load, which is the proportion of the WMH volume to the total volume of white matter,” said lead study author, Dr. Wartolowska.
Researchers found that a higher load of WMH was strongly associated with current systolic blood pressure. Still, the strongest relationship was found for past diastolic blood pressure, particularly in those under the age of 50. In patients who were taking high blood pressure medication, any increase in blood pressure, even below the usual treatment threshold of 140 mmHg for systolic and below 90 mmHg for diastolic, was linked to an increase in WMH.
The study concluded that there was a strong association between diastolic blood pressure before the age of 50 and brain damage in later life, even if the diastolic blood pressure was usually considered to be in a healthy range. This suggests that even slightly elevated blood pressure can have a damaging effect on brain tissue even before it meets the criteria for treating hypertension.
Researchers do caution that further analysis is needed to identify differences in white matter that may be associated with other conditions. These may include high cholesterol levels, obesity, and kidney problems.
Dr. Wartolowska concluded, “Our results suggest that to ensure the best prevention of white matter hyperintensities in later life, control of diastolic blood pressure, in particular, may be required in early midlife, even for diastolic blood pressure below 90mmHg, whilst control of systolic blood pressure may be more important in late life. The long time interval between the effects of blood pressure in midlife and the harms in late-life emphasizes how important it is to control blood pressure long-term, and that research has to adapt to consider the very long-term effects of often asymptomatic problems in midlife.”