High Blood Pressure or Irregular Heartbeat Linked to Alzheimer's Disease Progression
Alzheimer’s disease (AD) may progress more rapidly in people with high blood pressure or a form of irregular heartbeat, atrial fibrillation, according to results of a Johns Hopkins study published in the Nov. 6, 2007, issue of Neurology. The findings suggest that treating these conditions may also slow memory loss in people with AD.
While current medications for Alzheimer’s disease are effective for some patients in slowing the rate of AD progression, many patients do not benefit from the treatments or cannot tolerate them, says lead researcher Michelle M. Mielke, Ph.D., of the Department of Psychiatry and Behavioral Sciences at The Johns Hopkins University School of Medicine.
"The possibility that specific vascular conditions may affect how fast a person with AD declines," Mielke says, "provides new opportunities for slowing the rate of AD progression. Treatments for atrial fibrillation and high blood pressure are relatively inexpensive and safe and may reduce memory decline in AD patients with these conditions."
The study examined 135 men and women over 65 who were newly diagnosed with AD. All had undergone annual memory tests for an average of three years.
Results showed that 10 with high blood pressure (systolic pressure over 160) at the time of AD diagnosis showed a rate of memory loss roughly 100 percent faster than those with normal blood pressure.
In addition, 10 with atrial fibrillation at the time of the diagnosis showed a rate of memory decline that was 75 percent faster than those with normal heartbeats.
The study participants were part of the Cache County Study on Memory Health and Aging, which has been following a group of 5,092 people 65 or older living in Cache County, Utah, since 1995.
"What makes this group and study unique is that we have been following these participants in the community for over a decade, even before they were first diagnosed with AD, so we know a good deal about their medical history," says Mielke. "Studies that enroll AD patients only from clinics may miss key factors, such as date of onset and history of cardiovascular disease and treatment."
Mielke says she is currently working on similar studies using larger sample sizes to better understand the potential role that vascular factors play before AD diagnosis and their role over the course of the disease’s progression.
Mielke also recently contributed to a study by Johns Hopkins psychiatrist Paul Rosenberg, M.D., that examined drugs that modify high blood pressure and high cholesterol, such as beta-blockers, diuretics, calcium-channel blockers and statins, and their effects on cognitive and functional decline. Results from that study are expected to be released this year.
Constantine Lyketsos, M.D., Paul Rosenberg, M.D., and Peter Rabins, M.D., M.P.H. of the Department of Psychiatry and Behavioral Sciences at The Johns Hopkins University School of Medicine also contributed to this study. Additional researchers include JoAnn Tschanz, Ph.D., Maria Norton, Ph.D., Ron Munger, Ph.D., Larry Cook, and Chris Corcoran, Ph.D., of Utah State University in Logan, Utah; Kathleen Hayden, Ph.D., and Kathleen Welsh-Bohmer, Ph.D., of Duke University in Durham, N.C.; Robert Green, M.D., of Boston University; and John Brietner, M.D., of the University of Washington in Seattle.
This study was supported by grants from the National Institute on Aging.