Sleep apnea is known to wreak havoc with the body, contributing to heart problems, diabetes and liver disease.

The sleep disorder also appears to have direct effects on brain health, a new study shows.

People with sleep apnea appear to experience accelerated aging of the brain’s white matter, which serves to connect the various regions of the brain, researchers reported Dec. 18 in the journal Neurology.

Sleep apnea also is associated with an increase in the size of the hippocampus, the part of the brain responsible for memory and thinking, researchers said.

“Both brain shrinkage and brain growth can harm memory and thinking by disrupting normal brain functions, increasing the risk of cognitive decline and dementia,” lead researcher Dr. Alberto Ramos, a neurologist and sleep medicine specialist with the University of Miami, said in a news release from the school.

People with sleep apnea stop breathing while asleep. This causes their brain to jolt them to wakefulness, at least enough for them to resume breathing.

Over time, untreated sleep apnea can increase a person’s risk of developing heart disease, Type 2 diabetes, fatty liver disease and mood disorders, according to the Sleep Foundation.

But researchers suspected that sleep apnea might do damage to the brain as well, Ramos said.

“Some studies have found sleep problems and lower oxygen levels during sleep have been linked to brain shrinkage while others have found a link to brain growth," he noted.

For this study, researchers tracked the health of nearly 2,700 Hispanic seniors with an average age of 68.

“Our study looked at Latino people, who have a higher risk of dementia when compared to non-Latino white people,” Ramos said.

The participants all had a take-home sleep test that measured the number of sleep disruptions they experienced.

About 56% of the people had no sleep problems, compared to 28% who had mild sleep problems and 16% who had moderate to severe sleep problems.

Brain scans taken 10 years after the sleep test showed that those with the most sleep problems had greater brain volume in the hippocampus, results show.

In fact, the size of the hippocampus increased with the number of sleep disruptions a person experienced, researchers said.

Lower oxygen levels during sleep were also associated with increase hippocampal volume, as well as changes in white matter.

“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,” Ramos concluded.