Cognitive Decline and Blood Pressure: New Studies Shed Light on the Link

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Mounting research suggests that having high blood pressure in midlife may harm your brain down the line—and that taking aggressive measures to lower elevated blood pressure might help preserve cognition. Indeed, the National Institutes of Health (NIH) and several Alzheimer’s disease associations list keeping blood pressure at healthy levels as one of the steps to help maintain cognitive health. While there’s still much to learn about how blood pressure and brain health are linked, three studies published over the last few months have added important evidence:

  • In a study in Lancet Neurology, researchers analyzed data from 465 British people born in 1946. The participants had their blood pressure measured at five points between ages 36 and 69 and received a brain imaging test between ages 69 and 71. Higher systolic blood pressure (the upper number) and higher diastolic blood pressure (the lower number) at age 53, and higher diastolic pressure alone at age 43, were associated with more white matter lesions—a sign of cerebral small vessel disease, which increases the risk of cognitive decline—on the later-life brain scan. Blood pressure at ages 60 and older was not associated with white matter lesions. In addition, greater increases in blood pressure between ages 36 and 53 were linked with smaller brain volume in older age. Decreased brain volume is associated with increased cognitive impairment and dementia. The authors concluded that “blood pressure monitoring and interventions might need to start around 40 years of age to maximize late-life brain health.”
  • A study in the Journal of the American Medical Association (JAMA) included more than 4,700 U.S. adults who had their blood pressure measured at five medical visits over 24 years, starting at midlife (defined in the study as ages 44 to 66). They were screened for dementia at the fifth visit and at a subsequent visit about six years later. Overall, 516 people developed dementia between the fifth and sixth visits. Compared to participants who had normal blood pressure, those who had hypertension in midlife were 41 percent more likely to develop dementia, regardless of whether their late-life blood pressure was high, low, or normal. The risk was highest among those who had high blood pressure in middle age but low blood pressure (hypotension) in older age.
  • Another study in JAMA looked at data from 449 people with hypertension (average age 67) who were randomly assigned to receive either “intensive” blood pressure treatment (that is, to reduce their systolic blood pressure to a “normal” target of less than 120 mm Hg) or standard treatment (to reduce systolic blood pressure to 140 or lower). The participants were part of the SPRINT MIND study, an offshoot of the landmark NIH-funded SPRINT study, which looked at the effect of intensive versus standard blood-pressure control on cardiovascular disease and cancer. MRI scans showed that, compared to individuals in the standard blood pressure target group, those in the intensive-treatment group had smaller increases in white matter lesions (the study’s primary endpoint) over four years. (Unexpectedly, and for unclear reasons, men in the intensive-treatment group lost slightly more of their total brain volume, a secondary endpoint.)

The study helps confirm the results of a related analysis from SPRINT MIND published earlier this year in JAMA. It found that, among 8,560 people, intensive blood pressure treatment lowered the incidence of mild cognitive impairment (MCI), a condition that sometimes progresses to dementia—though it didn’t impact the incidence of actual dementia during the study period.

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