Sleep apnea linked to changes in brain including enlarged hippocampus, finds research

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 disruptions per hour, or no sleep problems; those with five to 15 disruptions, 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, participants had brain scans to measure brain volume and white matter hyperintensities, areas in the white matter where the brain tissue has been damaged.

After adjusting for factors such as age, sex, high blood pressure and whether a participant had insurance, they found that people in the group with the most sleep problems had 0.24 cubic centimeters (cm3) greater brain volume in the hippocampus than those with no sleep problems.

They also found that for each additional sleep disruption, there was a 0.006 cm3 increase of brain volume in the hippocampus. Researchers found lower oxygen during sleep was also associated with increased hippocampal volume as well as increased white matter hyperintensities.

“Our findings highlight the complex relationships between sleep health and brain aging and show there is a need for longer studies that follow people beginning 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 people can receive early and effective treatment, especially in people who may be at higher risk for dementia.”

A limitation of the study was that it only included Latino adults, so results may not be the same for other populations.

Reference:

Alberto R. Ramos, Christian Agudelo Sleep Disordered Breathing and Subsequent Neuroimaging Markers of Brain Health in Hispanic/Latino Adults, Neurology, https://doi.org/10.1212/WNL.0000000000210183