People with breathing problems during sleep may have a larger hippocampus, the brain region responsible for memory and thinking, according to a study published in the Dec. 18, 2024, online issue. Neurology®the medical journal of the American Academy of Neurology. The study, which mainly involved Latino people, also found that people with lower oxygen levels during sleep showed changes in the deep parts of the brain, the white matter, a common finding of impaired brain health that develops with the age.
Sleep-disordered breathing is a range of conditions that cause abnormal breathing during sleep, including snoring and obstructive sleep apnea. Obstructive sleep apnea occurs when a person stops breathing five or more times per hour. When breathing stops, oxygen levels can drop, affecting the brain.
Some studies have found that sleep problems and lower oxygen levels during sleep have been linked to brain shrinkage, while others have found a link to brain growth. Both brain shrinkage and brain growth can harm memory and thinking by disrupting normal brain functions, increasing the risk of cognitive decline and dementia. Our study looked at Latino people, who have a higher risk of dementia compared to non-Latino white people.”
Alberto R. Ramos, MD, study author from the University of Miami and Fellow of the American Academy of Neurology
The study involved 2,667 Latino people with an average age of 68.
At the start of the study, each participant was given a take-home sleep test that measured how often they stopped breathing, called apneas, and how often they had slow or shallow breathing, called hypopneas.
They were divided into three groups: those who had fewer than five sleep disturbances per hour, or had no sleep problems; those with five to fifteen disturbances, mild sleep problems; and those with more than 15, moderate to severe sleep problems. Of the total participants, 56% had no sleep problems, 28% had mild sleep problems, and 16% had moderate to severe sleep problems.
Researchers also measured oxygen levels in the bloodstream during sleep.
Ten years later, the participants were given brain scans to measure brain volume and white matter hyperintensity, areas in the white matter where brain tissue has been damaged.
After adjusting for factors such as age, gender, high blood pressure and whether a participant had insurance, they found that people in the group with the most sleep problems lost 0.24 cubic centimeters (cm3) greater brain volume in the hippocampus than those without sleep problems.
They also found that for every additional sleep disruption, there was 0.006 cm3 increase in brain volume in the hippocampus. Researchers found that lower oxygen levels during sleep were also associated with increased hippocampal volume and increased white matter hyperintensity.
“Our findings highlight the complex relationships between sleep health and brain aging and show the need for longer studies that follow people starting in middle age or earlier,” Ramos said. “A clear understanding of how brain volume is affected by sleep apnea and other sleep disorders is essential so that people can receive early and effective treatment, especially in those who may be at higher risk for dementia.”
A limitation of the study was that it included only Latino adults, so results may not be the same for other populations.
The study was supported by the National Institute on Aging.
Source:
Magazine reference:
Ramos, A.R., et al. (2024) Sleep-disordered breathing and subsequent neuroimaging markers of brain health in Hispanic/Latino adults. Neurology. doi.org/10.1212/WNL.0000000000210183.