Systolic blood pressures above 130 millimeters of mercury in middle age were associated with an increased risk of dementia later on, according to a longitudinal study published June 12 in the European Heart Journal.
Notably, these blood pressure levels were only predictive of later dementia when measured in 50-year-olds as part of the Whitehall II cohort study. When the same group had BPs taken at ages 60 and 70, those readings weren’t significantly associated with dementia—suggesting long-term exposure is an important factor in this development.
“The findings of this longitudinal observational study of over 8,000 men and women support the hypothesis that hypertension in mid-life but not late life is associated with increased risk of dementia,” wrote lead author Jessica G. Abell, PhD, with the French Institute of Health and Medical Research, and colleagues. “We show that high SBP at age 50 was associated with increased risk of dementia, much under the conventional 140 mm Hg threshold used to define hypertension.”
The American Heart Association/American College of Cardiology opted to lower the bar for hypertension to 130/80 mm Hg in guidelines released in November, but European guidelines still use the 140/90 cutoff.
Abell et al. found a systolic BP above 130 at age 50 was associated with 38 percent increased odds of dementia, even after adjustment for other risk factors. Dementia was diagnosed at an average age of 75.2 years old.
“Our results show excess risk of dementia is also present in those free of cardiovascular disease,” the authors wrote. “These results suggest that subclinical or ‘silent’ vascular brain lesions (i.e. infarcts, microbleeds, white matter changes), which are common in those with hypertension, may be involved in increased dementia risk in those with high blood pressure who do not have clinical cardiovascular disease. Thus, cerebral small vessel disease is likely to be an important mechanism underlying the association of high blood pressure and cognitive dysfunction.”
The researchers said larger studies are needed to confirm the link between elevated mid-life blood pressure and dementia, and to begin investigating preventive treatments for this relationship.