Decreased blood flow and destruction of blood vessels in the brain have been linked to aging and age-related dementia. Using a large-scale brain imaging study that looked at cerebral blood flow, researchers have identified several conditions that cause the brain to age faster.
In one of the largest studies of its kind, scientists used single photon emission computed tomography (SPECT) to scan the brains of 31,227 individuals aged 9 months to 105 years. they performed the scans twice: one at rest and the other during a task that involved concentration.
The team—made up of scientists from Amen Clinics, Google, John’s Hopkins University, University of California, Los Angeles and the University of California, San Francisco—studied blood flow in 128 brain regions to predict the age of each individual, and to identify lifestyle and disease factors that might accelerate the loss of cerebral blood flow.
They found that several brain disorders and behaviors could accelerate aging. Schizophrenia was the worst contributor, adding an average of four years of premature aging. Cannabis abuse, bipolar disorder, attention deficit hyperactivity disorder (ADHD) and alcohol abuse each contributed 2.8 years, 1.6 years, 1.4 years and 0.6 years, respectively, according to the team’s analysis, published in the Journal of Alzheimer’s Disease.
“Better treatment of these disorders can slow or even halt the process of brain aging," said the study’s lead author Daniel Amen, a psychiatrist and founder of Amen Clinics, in a statement.
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Many previous studies have shown that decreased cerebral blood flow is related to aging, as well as Alzheimer’s. A 2014 study in Nature Communications, for example, found that certain amyloid-beta mechanisms would change endothelial cells that form blood vessels. That would lead to a reductions in cerebral blood flow, and hence insufficient delivery of oxygen and glucose to brain cells, causing neuronal damage seen in Alzheimer’s dementia.
A recent study by scientists from the University of Virginia and Virginia Tech connected Alzheimer’s and age-related dementia to the brain’s lymphatic vessels, which are structured like blood vessels. Once believed to be nonexistent, meningeal lymphatic vessels drain waste like amyloid-beta from the central nervous system, and decreased flow would lead to harmful protein buildup in the brain, according to the team’s findings.
Amen and his colleagues suggest that SPECT scan can help indicate if a patient’s brain is aging too fast so that they can start prevention or management of symptomatic cognitive problems. Moreover, understanding the contributing factors of brain aging could provide guidance to slow the process and maintain cognitive function.