Higher than normal blood pressure is linked to more extensive brain damage in elderly people, according to a new study published in the European Heart Journal.
In particular, the study found that there was a strong association between diastolic blood pressure (DBP) before the age of 50 years and brain damage in later life, even if DBP was within normal considered range.
The findings come from a study of 37,041 participants enrolled in UK Biobank, aged 40-69 years, and for whom medical information including magnetic resonance imaging (MRI) brain scans was available.
Researchers from the Centre for Prevention of Stroke and Dementia at the University of Oxford examined MRIs for white matter hyperintensities (WMHs), which are known to be associated with an increased risk of stroke, dementia, refractory depression and functional decline in older age.
They found WMHs were more strongly associated with concurrent systolic blood pressure (SBP) (DBP: b=0.064; 95% CI, 0.050-0.078 vs SBP: b=0.076; 95% CI, 0.062-0.090), but the strongest association was for past DBP (DBP: b=0.087; 95% CI, 0.064-0.109 vs SBP: b=0.045; 95% CI, 0.022-0.069), particularly below the age of 50 years (DBP: b=0.103; 95% CI, 0.055-0.152 vs SBP: b=0.012; 95% CI, −0.044 to 0.069).
Due to the higher prevalence of elevated SBP, median WMH increased 1.126 per 10 mmHg usual SBP and 1.106 per 5 mmHg usual DBP. The population attributable fraction of WMH in the top decile was greater for elevated SBP (19.1% for concurrent SBP vs 24.4% for past SBP).
Any increase in BP, even <140 mmHg for SBP and <90 mmHg for DBP, and especially if requiring antihypertensive medication, was associated with increased WMH.
Lead author, Dr Karolina Wartolowska said: “Not all people develop these changes as they age, but they are present in more than 50 per cent 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.”
She said: “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.”
As MRI scans were only available at one time point, the researchers could not quantify the progression of WMH directly.
