Data from more than 37k patients in the UK Biobank study suggests hypertension in midlife was linked to an increased risk of white matter hyperintensities later in life.
Karolina Wartolowska, MD, DPhil
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Data published from researchers at the Wolfson Centre for Prevention of Stroke and Dementia at Oxford University suggests high blood pressure in midlife was linked to an increased risk of brain damage later in life.
Results of the study, which examined both systolic and diastolic blood pressure before the age of 50 and brain damage later in life, revealed patients with higher blood pressure were more likely to have a higher volume of white matter hyperintensities as they grow older.
“The study showed that diastolic blood pressure in people in their 40s and 50s is associated with more extensive brain damage years later. This means that it is not just the systolic blood pressure, the first, higher number, but the diastolic blood pressure, the second, lower number, that is important to prevent brain tissue damage,” said Karolina Wartolowska, a clinical research fellow at the Centre for Prevention of Stroke and Dementia, University of Oxford, in a statement. “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.”
With an interest in the effect of blood pressure control on potential brain damage, Wartolowska and colleagues from Oxford University designed their analysis as a community-based cohort study using data from more than 35,000 patients in the UK Biobank Study. Patients included in the study were between 40-69 years of age, had data collected between March 2006 to October 2010, and underwent magnetic resonance imaging between August 2014 and October 2019.
Of note, patients were not eligible for inclusion if they had missing blood pressure data at baseline or missing MRI data. Patients were also deemed ineligible if they had previous diagnoses of conditions such as conditions, such as multiple sclerosis or other demyelinating disorders, cerebral infarction, encephalitis or brain abscess, brain tumor, or systemic lupus erythematosus.
For the purpose of analysis, investigators hoped to assess associations between white matter hyperintensities load and concurrent versus past blood pressure using models adjusted for factors including age, sex, cardiovascular risk factors, blood pressure source, assessment center, and time since baseline. Investigators pointed out associations adjusted for regression dilution bass were determined between median white matter hyperintensities and usual systolic or diastolic blood pressure, stratified by age and baseline blood pressure readings.
In total, 37,041 patients were deemed eligible for inclusion in the study and these patients had a median time between visits of 9.07 (4.28-13.49) years. Investigators noted these patients were similar to those in the overall UK Biobank population but did contain more active smokers and fewer people with a history of diabetes, angina, myocardial infarction, or antihypertensive medication use.
Upon analysis, results indicated white matter hyperintensities were more strongly associated with concurrent systolic blood pressure(DBP: ß=.064; 95% CI, 0.050–0.078; SBP: ß=.076; 95% CI, 0.062–0.090) but revealed the strongest association was for past diastolic blood pressure (DBP: ß=.087; 95% CI, 0.064-0.109; SBP: ß=.045; 95% CI, 0.022–0.069), especially those under 50 year of age (DBP: ß=.103; 95% CI, 0.055-0.152; SBP: ß=.012; 95% CI ,-0.044 to 0.069).
Additionally, because of the higher prevalence of elevated systolic blood pressure, investigators determined median white matter hyperintensities increased 1.126 (95% CI, 1.107–1.146) per 10 mmHg increase in usual systolic blood pressure and 1.106 (95% CI 1.090–1.122) per 5 mmHg increase in diastolic blood pressure. Results also suggested the population attributable fraction of white matter hyperintensities in the top decile was greater for elevated systolic blood pressure—19.1% for concurrent and 24.4% for past systolic blood pressure). Furthermore, results indicated any increase in blood pressure, even among patients with systolic blood pressure below 140 mmHg and diastolic blood pressure below 90 mmHg or those on antihypertensive medications, was associated with increased white matter intensities.
"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,” Wartolowska added.