High blood pressure in middle age is associated with the development of more extensive brain damage when elderly, researchers report today.
Research published in the European Heart Journal shows a particularly strong link between having diastolic high blood pressure before the age of 50 and brain damage in later life, even if the diastolic blood pressure was within a healthy range.
Lead researcher Dr Karolina Wartolowska, a clinical research fellow at the Centre for Prevention of Stroke and Dementia, University of Oxford, UK, looked for white matter hyperintensities (WMH), which are associated with an increased risk of stroke, dementia, physical disabilities, depression and a decline in thinking abilities.
WMH is present in more than 50% of patients over the age of 65 and most people over the age of 80 even without high blood pressure, but it is more likely to develop with higher blood pressure and more likely to become severe.
For the study, Dr Wartolowska and her team used data from 37,041 participants, all aged between 40 and 69 years, who were enrolled in UK Biobank between March 2006 and October 2010, for whom medical information, including MRI brain scans, was available.
They then used follow-up data, including MRI scans, between August 2014 and October 2019.
The researchers found that a higher load of WMH was strongly associated with current systolic blood pressure, but the strongest association was for past diastolic blood pressure, particularly when the individual was under the age of 50.
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 increased WMH, especially when people were taking medication to treat high blood pressure.
For every 10mmHg increase in systolic blood pressure above the normal range, the proportion of WMH load increased by an average of 1.126-fold and by 1.106-fold for every 5mmHg increase in diastolic blood pressure.
Among the top 10% of people with the greatest WMH load, 24% of the load was attributed to having a systolic blood pressure above 120mmHg, while 7% was attributed to having diastolic blood pressure above 70mmHg.
Dr Wartolowska said: “We made two important findings. Firstly, the study showed that diastolic blood pressure in people in their 40s and 50s is associated with more extensive brain damage years later.
“Many people may think of hypertension and stroke as diseases of older people, but our results suggest that if we would like to keep a healthy brain well into our 60s and 70s, we may have to make sure our blood pressure, including the diastolic blood pressure, stays within a healthy range when we are in our 40s and 50s.
“The second important finding is that any increase in blood pressure beyond the normal range is associated with a higher amount of white matter hyperintensities. This suggests that even slightly elevated blood pressure before it meets the criteria for treating hypertension has a damaging effect on brain tissue.”
Because MRI scans were only available at one time point, the researchers say they were unable to quantify the progression of WMH directly and they add that further analysis is needed to identify differences in different regions of white matter.
Wartolowska KA, Webb AJS. Midlife blood pressure is associated with the severity of white matter hyperintensities: analysis of the UK Biobank cohort study. European Heart Journal 26 November 2020; doi:10.1093/eurheartj/ehaa756
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