Blood Pressure Associated With Alzheimer’s Disease

In the past decade, researchers have studied the association between blood pressure, among older people, and Alzheimer’s disease. Recently, more studies with concordant results have shown that the elderly with hypertension ( high blood pressure ) are more likely to have biomarkers of Alzheimer’s.

Alzheimer’s is a chronic neurodegenerative disease which is a common type of 60-70% of dementia cases. Outside of the genetic makeup and other risk factors such as head injuries, depression, scientists strongly believe and postulate that the adequate control of blood pressure and its drugs may reduce Alzheimer’s risk.

“Hypertension indicates that the heart is working harder than normal to pump blood throughout the body which not only causes the heart to pump harder to move blood through the narrowed arterial pipes but can also result in reduced blood flow to body regions that need oxygen and glucose.” This leads to brain dysfunction such as cognitive function: memory and language. 

According to the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study, nearly 1,500 middle-aged participants were examined for over 20 years to identify who developed dementia (Kivipelto et al., 2005), middle-aged adults with hypertension had a threefold increased risk for dementia. Similarly, the Honolulu-Asia Aging longitudinal study, which included a 28-year follow-up on Japanese-American men, indicated that an increase in blood pressure from midlife (age: 40-64 years) was predictive of late-life dementia.

The age at diagnosis of elevated blood pressure could be a determinant of the relationship between hypertension and Alzheimer’s disease 10–20 years later. According to the Joint National Committee VII, the Honolulu-Asia Aging Study reported an increased risk for the development of late-age Alzheimer’s disease in untreated hypertensive men.

Researchers from the Honolulu-Asia Aging Study also showed that “autopsies were performed on 774 of the men after they died, most of whom had suffered from high blood pressure or were being treated for the disease. About 15 percent were taking a beta-blocker alone, while another 18 percent were taking a beta blocker along with another blood pressure medication.” Beta-blocker is the most common drug treatment for high blood pressure including acebutolol (Sectral), atenolol (Tenormin), bisoprolol (Zebeta), metoprolol, nadolol (Corgard), nebivolol (Bystolic) and propranolol (Inderal LA). These participants showed the least signs of brain abnormalities of Alzheimer’s such as: less brain shrinkage or fewer microinfarcts.

On the other hand, the Kungsholmen project indicated that hypotension (low blood pressure) may also be harmful as well because low blood pressure induces or accelerates cognitive decline by lowering cerebral blood flow. It has also been postulated that orthostatic hypotension predicts cognitive impairment in the elderly population.

Although more geropsychologists,  neurologists, and psychologists are drawn to investigate this issue to promote healthy aging of both body and brain, we cannot deny that adequate control of blood pressure has been underrecognized in the preservation of brain and cognitive functioning with increasing age.