Is there a link between blood pressure and Alzheimer’s?
According to a new study, blood pressure may be one of the risk factors that make the brain more vulnerable to dementia, including the formation of brain lesions typical of diseases like Alzheimer’s. Neurologist Dr Marcelle Smith, practising at Mediclinic Sandton, explains.
Dr Marcelle Smith, a neurologist at Mediclinic Sandton, explains that the association between high blood pressure and dementia has been anecdotal for many years – and the results of this study, published in July in the online issue of Neurology, has reinforced this link.
What is blood pressure?
Blood pressure is the pressure of circulating blood on the walls of blood vessels. It is regarded as one of the body’s vital signs, together with heart rate, respiratory rate, oxygen saturation and body temperature. It is usually expressed in terms of systolic pressure (maximum pressure during one heartbeat) over diastolic pressure (minimum pressure between two heartbeats). The ideal blood pressure is 120/80. Blood pressure is considered high once it exceeds 140/90.
How does blood pressure affect the brain?
High blood pressure leads to the stiffening and narrowing of blood vessels in the brain, making them susceptible to bleeding. It can also cause blockages in the vessels, which can result in infarcts, or lesions, on the brain, which is the most common cause of stroke.
“One or two brain lesions can go undetected, but as these lesions accumulate, they can affect the functioning of the brain. Deep in the white matter of the brain are the fibres responsible for integrating information for the brain’s higher functioning, such as memory, planning and processing. When there is damage along these pathways, these functions can no longer work properly, leading to memory impairment, cognitive decline and, in some cases, even personality changes,” explains Dr Smith.
What is dementia?
Dementia is an acquired condition that involves the progressive deterioration of a person’s higher functions, memory being the most common of those functions. Dementia can be caused by a range of factors, all of which have not been fully identified. Alzheimer’s is a type of dementia. The more risk factors a person has, the higher their chances of developing problems in the brain usually associated with vascular dementia.
Genes play a role
“We’re all at the mercy of our genetics, unfortunately. You’ll find that some people may have high blood pressure, and take no medication to control it, yet not develop problems with the brain, heart or kidneys, while the next person, in similar circumstances, might have serious health problems. There is definitely a genetic predisposition that makes some people more vulnerable than others, but maintaining a normal and healthy blood pressure is important in preventing those complications,” says Dr Smith.
“There are many risk factors to getting dementia, and the more of those factors a person has, the more likely he or she will develop dementia. Controlling high blood pressure, whether through diet, lifestyle changes like regular exercise, or medication, is one of the ways to avoid dementia.”