A new study from the University of Wisconsin School of Medicine and Public Health shows people at risk for Alzheimer’s disease who have high blood pressure or are overweight experience declines in memory and thinking skills at double the rate compared to those without hypertension or obesity. In this study hypertension in participants was both treated and untreated.
While these are subtle cognitive changes year-to-year, the research suggests adults who have increased Alzheimer’s disease-related brain changes and are also hypertensive or obese would be expected to cross from normal memory to mild cognitive impairment earlier than if they maintained healthy blood pressure and weight during middle age.
The study, “Hypertension and Obesity Moderate the Relationship between Beta-amyloid and Cognitive Decline in Midlife,” was recently published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. Lindsay R. Clark, PhD, a neuropsychologist and assistant professor of medicine in the University of Wisconsin School of Medicine and Public Health, is lead author.
“There is no cure for Alzheimer’s disease, and current treatments offer limited effectiveness in delaying or changing the course of the disease,” said Clark. “By studying modifiable risk factors, we hope to find ways people can maintain or improve brain health. This current research is exciting because while we can’t control Alzheimer’s disease-related brain changes, we can control blood pressure and weight.”
Clark and her team studied 207 cognitively-unimpaired participants from the Wisconsin Registry for Alzheimer’s Prevention (WRAP), the largest family history study of Alzheimer’s disease in the world. Participants were between the ages of 40 and 70, and 73 percent had at a minimum of one parent with Alzheimer’s disease. Over a period of eight or more years, participants completed a minimum of three study visits that included verbal learning and memory testing, as well as at least one brain imaging scan or cerebral spinal fluid collection through a lumbar puncture to measure levels of amyloid protein in the brain. The presence of increased amyloid in the brain is a known risk factor for Alzheimer’s disease, but not all older adults with elevated levels of amyloid in their brains experience cognitive declines by late life.
Dr. Clark and her co-authors found participants who had elevated levels of amyloid in their brains, and either high blood pressure or obesity, experienced twice as fast cognitive declines than participants with elevated amyloid and healthy weight and blood pressure. Participants with normal levels of amyloid who were obese or had high blood pressure did not show faster rates of change on their cognitive tests. In this study, researchers defined high blood pressure as systolic readings over 140 and diastolic readings over 90, and obesity was defined as a waist circumference measurement greater than 88 cm/ 35 inches for women and greater than 102 cm/ 40 inches for men.
“This study showed the presence of some modifiable risk factors in people with elevated levels of amyloid in their brains changed the rate of memory decline,” said Clark. “Our next step will be to follow up with more studies to see if treating hypertension or obesity in midlife slows the rate of memory loss in those with amyloid buildup and delays the onset of clinical symptoms of dementia in later life.”
This research supports a growing number of findings that suggest lifestyle changes can prevent, delay, or lessen the severity of the onset of dementia due to Alzheimer’s disease.
In recent years, scientists have shown amyloid buildup in the brain can occur more than a decade before people begin to experience the clinical changes of Alzheimer’s disease, such as declines in memory and thinking abilities, and personality changes. Alzheimer’s disease researchers at the University of Wisconsin focus on improving early detection of Alzheimer’s disease, identifying risk and protective factors, and finding ways to delay onset and progression.
Dr. Clark’s University of Wisconsin co-authors include Rebecca L. Koscik, PhD, Samantha L. Allison, PhD, Sara E. Berman, PhD, Derek Norton, MS, Cynthia M. Carlsson, MD, Tobey Betthauser, PhD, Barbara B. Bendlin, PhD, Bradley T. Christian, PhD, Nathaniel Chin, MD, Sanjay Asthana, MD, and Sterling C. Johnson, PhD.