The researchers, who monitored 1,900 older African-American men and women for five years, found that the continuous use of medications to lower blood pressure reduced the risk of memory loss by more than a third.
"We have a lot of medications that keep people alive longer, but few to maintain their memories," says Michael D. Murray, PharmD, M.P.H., a research scientist at The Regenstrief Institute, professor of pharmacy at Purdue University, adjunct professor of medicine at the IU School of Medicine and first author of the study. "We have now shown that antihypertensive medications can decrease the risk of cognitive impairment as well as lower the risk of stroke, myocardial infarction and end-stage renal disease
This is the first study to find a relationship between medication taken to control high blood pressure and cognitive impairment in older African-Americans, although previous studies suggest that use of antihypertensive medication by Caucasian older adults with high blood pressure preserves cognition. Cognitive impairment is defined as a measurable change in cognitive function.
"Our study provides older African-Americans with yet another reason, in addition to preventing stroke, heart attacks and kidney problems, to take their blood pressure pills," says Dr. Murray.
All the participants were free of cognitive impairment at the beginning of the study and two thirds had high blood pressure. This is the largest longitudinal study to date on the cognitive effects of drugs in older adult African-Americans.
According to the National Center for Health Statistics approximately a quarter of Americans between the ages of 20 to 74 years are hypertensive. More than three-quarters of women age 75 and older in the U.S. have hypertension as do 64 percent of men in the same age range. The prevalence of hypertension is 60 percent greater in African-Americans, and their risk of stroke is 80 percent greater than Caucasians.
"This analysis is part of the ongoing Indianapolis-Ibadan dementia project, a study which is designed to identify potentially modifiable risk factors for Alzheimer disease by comparing the disease in two populations from a developed and developing country - African- Americans living in Indianapolis and Yoruba living in Ibadan, Nigeria," said Hugh Hendrie, MBChB, research scientist at the Regenstrief Institute and professor of psychiatry at the IU School of Medicine.
Drs. Murray, Hendrie, and colleagues recently began a four-year study sponsored by the National Heart, Lung, Blood Institute to determine whether minority and low-income patients with high blood pressure take their medications better when they are helped by a pharmacist and provided with special medication information aimed at persons with low health literacy. The trial will last four years and will determine whether this medication support improves the medication-taking and reduces blood pressures of these patients.
In addition to Dr. Murray and Dr. Hendrie, co-authors of the Archives of Internal Medicine study on antihypertensive medication and preservation of cognition in older African-Americans are Kathleen A. Lane, M.S., Sujuan Gao, Ph.D., Rebecca M. Evans, M.D., Frederick W. Unverzagt, Ph.D. and Kathleen S. Hall, Ph.D.
This study was supported by a grant from the National Institute on Aging.