En español | Two new studies out this week indicate that having high blood pressure at midlife has a long-term impact on brain health.
The first report, from the European Heart Journal, published June 12, says that even "mild" high blood pressure — systolic blood pressure of 130 mmHg — at age 50 is associated with a significantly increased risk of dementia.
That’s eyebrow-raising news, because many medical experts, such as the UK’s National Institute for Health and Care Excellence and the European Society of Cardiology, recommend blood pressure medication only when systolic blood pressure is over 140. The American Heart Association and American College of Cardiology recently lowered the stage 1 hypertension threshold to 130.
But even 130 may not be good enough. “Our results show high blood pressure (over 130) at age 50 increases risk of dementia later in life,” says Archana Singh-Manoux of the French National Institute of Health and Medical Research in Paris,a senior author of the new study.
“There’s some evidence that 120 or below should be the target for people in midlife,” says Alzheimer’s Association Global Science Initiatives Director James A. Hendrix.
Of the 8,639 people in the study, whose blood pressure was measured in 1985 when they were ages 35 to 55 and again in 1991, 1997 and 2003, 385 had dementia by 2017. The average age of dementia onset was 75. People with systolic blood pressure of 130 or more at 50 had a 45 percent greater risk of developing dementia than those with a lower systolic blood pressure at 50. Even those with no heart or blood-vessel disease — long known to be associated with high blood pressure — showed major increased dementia risk.
The second study, published June 13 in Cardiovascular Research, also says that high blood pressure puts people at higher risk of dementia, and shows for the first time that an MRI can detect very early signatures of neurological damage from hypertension before any dementia symptoms occur. "Being diagnosed with high blood pressure in, say, your 50s may predict a dementia risk in your 70s and 80s," says neuropsychiatrist Constantine Lyketsos of the Johns Hopkins University School of Medicine. "The mechanism is not clear, but it's probably because moderately ... elevated blood pressure in midlife slowly erodes the blood vessels in the brain and affects the blood supply to the deeper tissues of the brain over the years."
Says Singh-Manoux, "High blood pressure damages small blood vessels, affecting parts of the brain responsible for thinking and memory."
But in the European Heart Journal study, those with high blood pressure first measured at 60 and 70 did not show increased dementia risk. "At older ages there is no robust association between high blood pressure and dementia," notes Singh-Manoux. This squares with a 2017 study in Alzheimer's & Dementia: The Journal of the Alzheimer’s Association, which found that systolic blood pressure between 140 and 159 actually lowered dementia risk for those past midlife. People who developed high blood pressure between ages 80 and 89 were 42 percent less apt to get dementia in their 90s compared with the normal-blood-pressure group. Those who got hypertension in their 90s had 63 percent less dementia risk than non-hypertensives the same age.
"Hypertension in the very old is not detrimental for mental health," said the 2017 study's lead researcher, Maria Corrada, a professor of epidemiology and neurology at the University of California, Irvine School of Medicine. "It's a matter of creating enough pressure to get blood to oxygenate the brain adequately,"
Says Hendrix, "You can get away with a little higher blood pressure when you're older. If you have low blood pressure when you're older, you may be categorized as frail, which can lead to fainting spells and falls. Older people with higher blood pressure seem to do better overall."
“The takeaway here is, people in midlife really need to look at their blood pressure," adds Hendrix, "and it’s not just a risk for heart disease; it’s also a risk for dementia as we age. It’s particularly important in your 40s and 50s, because we really start to set ourselves up for dementia risk later in life. The brain starts to change 10 to 20 years before symptoms begin, so it’s important to recognize that and start making lifestyle changes long before symptoms occur.”
To improve your odds of a healthy second half of life, consider following AARP’s five lifestyle tweaks to help ward off dementia.