Megan Marples wrote this article in CNN:

High blood pressure in young adults is linked to smaller brain size and increased risk of dementia, a new study has found.

Adults who were diagnosed with hypertension between ages 35 to 44 had smaller brain sizes and were more likely to be diagnosed with dementia compared to adults their age with normal blood pressure, according to a study published Monday in Hypertension, a journal of the American Heart Association.

Adults under age 35 had the largest reductions in brain volume compared to adults their age without high blood pressure, which could come with adverse health effects, said Dr. James Galvin, professor of neurology at the University of Miami's Miller School of Medicine in Florida. He was not involved in the study.

"The smaller brain volumes in younger aged individuals as a consequence of their high blood pressure may put them at higher risk of dementia as they age," he said.

Researchers used magnetic resonance imaging (MRI) scans of 11,399 people ages 55 years and younger who were diagnosed with high blood pressure as well as 11,399 people without hypertension. The participants information came from the UK Biobank, a database of anonymous health information from around half a million people. The study authors did follow ups with participants over an average of 11.9 years later to see if they actually were diagnosed with dementia.

Hypertension is common in adults ages 45 to 64 and is associated with brain health and dementia later in life, but little is known about how the age of when high blood pressure is diagnosed affects these associations, said senior study author Dr. Mingguang He, professor of ophthalmic epidemiology at the University of Melbourne in Australia, in a statement.

"If this is proven, it would provide some important evidence to suggest earlier intervention to delay the onset of hypertension, which may, in turn, be beneficial in preventing dementia," he said.

Having a smaller brain volume means there is a loss of neurons and the connections they have with each other, said Donna Arnett, dean of the University of Kentucky College of Public Health in Lexington, who was not involved in the study.

Larger brain volumes are associated with better cognitive function while loss of brain volume is associate with the development of dementia, Galvin said. Hypertension over time impacts blood flow to the brain and can potentially damage the brain structure, he explained. If left untreated, it affects brain function, Galvin added.

Over time, young people may be impacted more because they face a longer lifetime duration of blood pressure on the brain, Arnett said.