Blood pressure, dementia and Alzheimer’s disease
By Arvind M. Dhople, Ph.D., Professor Emeritus, Florida Tech
Dementia is a major health concern for which prevention and treatment strategies remain elusive. Lowering high blood pressure with specific antihypertensive medications (AHMs) could reduce the burden of disease. When mild cognitive impairment subjects are followed longitudinally, they tend to convert to cardiovascular health, but also can reduce their risk of dementia and Alzheimer’s disease. This comprehensive look extends the previous preliminary data of SPRINT (Systolic blood Pressure Intervention Trial) that showed lowering blood pressure levels reduce the risk for a combination of dementia and mild cognitive clinically probable Alzheimer’s disease at a rate of 10-15% per year. This is in contrast to normal elder subjects who will develop Alzheimer’s disease at a rate of 1-2% per year.
According to a recent study, thorough examination of long-term data from four countries (United States, France, Iceland and the Netherlands), treating high blood pressure with medication not only improves older adults’ impairment. In this current SPRINT study, the scientists teamed up to analyze data from six comprehensive, community-based health studies conducted between 1987 and 2008 in those four countries. They examined all five major types of blood pressure medications – ACE inhibitors, angiotensin II receptor blockers, beta-blockers, calcium channel blockers and diuretics – and found that the type of medication did not make a difference.
Participant data was divided into two groups – 15,537people with high blood pressure and 15,553 people with normal blood pressure. In all, 1,741 diagnoses of Alzheimer’s disease and 3,728 cases of other dementias developed over time. People who controlled their blood pressure with medicine were found to have the same risk for developing dementia as individuals with normal blood pressure who did not require medication.
This team of scientists cross-referenced data from six large, longitudinal studies that tracked the health of all the people in the study (over age 55) across over 20 years of follow-up. They found that treating high blood pressure – no matter with which type of antihypertensive drug – reduced dementia by 12% and the risk of developing Alzheimer’s disease by 16%.
The investigators were pleased to work with a deeper data pool, allowing them to look at specific medication types used to keep blood pressure at same levels. The study also gave them much longer-term follow-up data, which were helpful to observe the gradual onset of dementia and Alzheimer’s symptoms. The large group of people studied also factored in additional health conditions common to older adults, giving them a clearer picture of the multiple issues that come with aging that are typically seen by general physicians.
Together with the SPRINT trial, this latest data adds to the evidence base that treating and reducing high blood pressure can also help reduce the risk of dementia. The researchers hope their findings add urgency to the need for better hypertension awareness among the rapidly growing global population of older adults, many of whom are at risk for developing high blood pressure or already have it but are not managing it properly.