Many people develop hypertension (high blood pressure) with age, putting them at risk of cardiovascular disease, chronic kidney disease, retinal damage, and stroke. Hypertension is also a risk factor for Alzheimer’s disease and dementia, due to damage caused by years of vessel injury, microbleeds, and lesions. Authors of a recent study report that hypertension diagnosed in early or midlife, but not late life, is a predictor of dementia.
Because hypertension damages the delicate small blood vessels of the heart, kidneys, eyes, brain, and other organs, it is a risk factor for a wide range of chronic diseases. Previous research has shown that hypertension, by restricting blood flow, reduces brain volume in key areas associated with dementia, such as the prefrontal cortex and hippocampus. As the number of young adults with hypertension increases to an estimated 1.6 billion globally by 2025, research on the risks of hypertension in earlier life are needed.
The authors collected data from more than 135,000 participants with hypertension and 135,000 matched control participants without hypertension from the United Kingdom Biobank, a long-term study of United Kingdom citizens. The researchers categorized participants into four categories: younger than 35 years; 35 to 44 years; 45 to 54 years; and 55 to 64 years. They used magnetic resonance imaging data to measure brain volume, and hospital records, death records, and self-reports to assess dementia status. Participants in the study provided data at a baseline appointment between 2006 and 2010 and at a follow-up appointment between 2014 and 2021.
Participants diagnosed with hypertension at any age had smaller brain volume than their matched control participant without hypertension. Participants diagnosed earlier in life had the greatest reductions, with participants diagnosed between ages 35 and 44 exhibiting a 0.8 percent loss in volume and participants before age 35 exhibiting a 1.2 percent loss. Specifically, hypertension was associated with loss of peripheral cortical gray matter, brain tissue necessary for higher brain functions such as learning, memory, and attention. Participants diagnosed with hypertension between ages 35 and 44 were at a 61 percent higher risk of dementia than the matched control participants without hypertension.
The authors concluded that hypertension diagnosed in early mid life, but not late life, is associated with decreased brain volume and increased risk of dementia. Lifestyle strategies that reduce blood pressure, such as exercise, sauna use, dietary modification, and stress management, may reduce dementia risk.