High blood pressure is the leading risk factor for stroke. Hypertension is perhaps the most controllable of the various risk factors and, with many effective medications available, it is frequently possible to get a patient’s blood pressure into the normal range with few side effects. Now comes a study from the medical journal, Neurology, suggesting that high blood pressure may have serious effects on the brain even in the absence of a stroke. I do not know whether hyperbaric oxygen can prevent or treat this kind of injury, but I want to call my readers’ attention to this valuable information.
Dr. Georgios Tsivgoulis of the University of Alabama at Birmingham, and colleagues studied nearly 20,000 patients who never had a stroke or TIA but who had elevated blood pressure. About half of the patients were already on some anti-hypertensive medications. Overall, nearly 8% of these patients had cognitive impairment identified using a six-item screener derived from the Mini-Mental State Examination. In patients 45 and older, elevated diastolic blood pressure was associated with cognitive impairment. Each 10 point increase over 90 mm Hg was associated with a statistically increased risk of cognitive impairment.
According to Dr. Tsivgoulis, experimental and pathological studies have shown that elevated diastolic blood pressure accelerates the normal atrophy of cerebral arterioles with age, which leads to ischemic white matter brain lesions. Presumably, these lesions account for the cognitive impairment.
Although Dr. Tsivgoulis’ study was subject to some potential confounding factors, I understand that NIH is planning a much larger study to determine whether aggressively treating blood pressure will have a beneficial effect on several outcomes, including cognitive impairment. In the meantime, Dr. Tsivgoulis points out that it is possible that treatment of hypertension could prevent at least some cognitive impairment as we age and I think, based on his study, that is a very reasonable conclusion.