Blood Pressure History May Affect Brain in Old Age
Age at which you develop hypertension is key to understanding risk for memory problems, study suggests
By Kathleen Doheny
WEDNESDAY, June 4, 2014 (HealthDay News) -- For years, doctors have preached that the lower the blood pressure, the better for preventing heart disease and stroke.
But a new study suggests that having low blood pressure in later years may be linked with worse memory, at least in those diagnosed with high blood pressure in middle age.
On the other hand, researchers linked high blood pressure in later life with greater risk of brain lesions for people who didn't have high blood pressure in their middle years. Brain lesions indicate damage and boost stroke risk.
"Our findings bring new insight into the relationship between a history of high blood pressure, blood pressure in old age, the effects of blood pressure on brain structure, and memory and thinking," said study researcher Lenore Launer, chief of neuroepidemiology at the U.S. National Institute on Aging.
History of high blood pressure appears to be the critical element in the link between blood pressure in old age and brain function, according to the study, published online June 4 in Neurology. It is also important to note that the research reveals links, not cause-and-effect relationships, between blood pressure levels, brain changes, and memory and thinking.
The research suggests two take-home points, said Dr. Gary Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City.
First, those who develop high blood pressure later in life can benefit from treatment, said Kennedy, who was not involved in the study. Second, those with high blood pressure in midlife who take medication to lower it should keep monitoring blood pressure in later life, he said. If the pressure becomes low, this study suggests it might put you at risk of dementia, he said.
The study didn't look at the mechanism, but Kennedy suspects the thinking and memory problems linked with lower blood pressure in old age may be linked with a decline in oxygen to the brain.
However, Kennedy cautioned against simply stopping your blood pressure medicine. "Check with your doctor," he said.
For the study, researchers measured the blood pressure of more than 4,000 adults in middle age, aged 50 on average. All were dementia-free at that time. The men and women had blood pressure measured again, at 76 years on average. At that time, MRIs assessed any damage to small blood vessels in the brain. The researchers also tested memory and thinking skills.
It's known that the relationship between blood pressure levels at middle age and later brain problems, including dementia, is complicated, Launer said.
Blood pressure levels tend to decline with age, and also decline when people experience dementia. Launer's team decided to look at midlife blood pressure and track the effects of both high and low blood pressure on the brain.