Is Hypertension Associated With an Accelerated Aging of the Brain?

Abstract

One of the first studies to examine the question of a potential negative impact of hypertension on the brain was published in 1971 in Science .1 Subsequently, many studies have been published, mainly on the relationship of blood pressure (BP) with cognitive performance, cognitive decline, and dementia.2 Their results were sometimes contradictory, some studies even suggesting that high BP could protect against the risk of dementia. This apparent contradiction created some confusion and a sense that this issue should not deserve much attention. The accumulation of data from high-quality population-based studies has helped us to decipher this riddle. Indeed, they have shown that the impact of hypertension on the brain strongly depends on when BP is measured in life. High BP in middle age is a risk factor for dementia, but not when measured at an old age. This age-dependent effect of exposure and the fact that, to fully evaluate its impact, hypertension should be assessed several decades before the onset of dementia have made it remarkably more complex to study the role of hypertension on the brain. Because of global aging, the number of dementia cases is skyrocketing around the world. The last World Health Organization report estimates that in 2010, 7.7 million persons have developed dementia, 1 new case every 4 seconds.3 The total number of people with dementia worldwide was estimated at 35.6 million in 2010 and is projected to reach 115.4 million in 2050. This ongoing epidemic of dementia and the absence of any preventive or curative treatment revived interest in studying modifiable risk factors of dementia, even if this relationship is complex as for hypertension. Indeed, simulation studies have shown that delaying by just a few months the entry into the clinical phase of the disease could enable, at the population level, …