High blood pressure may be potential risk factor for Alzheimer’s disease

Written by Peter Brown

A multidisciplinary panel of experts from the American Heart Association (Dallas, TX, USA) have potentially identified that chronic arterial hypertension in middle age may impair cognitive function and may act as a risk factor for Alzheimer’s disease.

The study, recently published in Hypertension, examined the impact of hypertension on cognition to assess the state of the knowledge, identify gaps and provide future directions.

Dementia affects approximately 30–40 million people worldwide, a number expected to triple by 2050 due to an aging population and other contributory factors. An estimated 80 million people in the USA have hypertension and the brain is commonly affected.  Apart from age, hypertension is a key risk factor for vascular problems in the brain that may result in stroke and dementia.

Previous research has established that chronic arterial hypertension is a risk factor for age-related dementia, such as Alzheimer’s or vascular dementia, with results indicating that high blood pressure disrupts the structure and function of cerebral blood vessels, leading to ischemic damage of white matter regions critical for cognitive function.

However, the link between hypertension, its treatment and cognition remains poorly understood, with some studies suggesting that it may improve cognition. This highlights “the complexities of recommending uniform levels of blood pressure across the life course,” wrote the expert panel.

Observational studies have demonstrated that high blood pressure causes atherosclerosis and other damage to the brain’s blood vessels, leading to reduced blood flow to brain cells. However evidence from clinical trials investigating anti-hypersensitive treatment improving cognition is not conclusive.

After carefully reviewing available literature, the panel concluded there are insufficient data to make evidence-based recommendations. However, judicious treatment of hypertension, taking into account goals of care and the patient’s individual characteristics, “seems justified to safeguard vascular health and, as a consequence, brain health,” concluded the panel.

Sources: Iadecola C, Yaffe K, Biller J et al. Impact of hypertension on cognitive function: a scientific statement from the American Heart Association. Hypertension. doi: 10.1161/HYP.0000000000000053 (2016) (Epub ahead of print);