THURSDAY, March 15, 2007 (HealthDay News) -- Some people with a moderate to severe form of the nighttime breathing disorder sleep apnea may be at an increased risk of stroke, a Japanese study finds.
Treating their sleep apnea might help lower that risk, however.
Specifically, sleep apnea sufferers who also have lesions caused by "silent brain infarction" and elevated levels of inflammatory markers associated with coronary artery disease may be at heightened stroke risk, the researchers said.
Silent brain infarction, also called subclinical cerebrovascular disease, is brain tissue death caused by lack of blood supply. Stroke in patients with sleep apnea is likely preceded by a silent brain infarction, which can be detected on MRI brain scans, the researchers said.
They looked for silent brain infarction in 50 men with obstructive sleep apnea.
"The percentage of silent brain infarction in patients with moderate to severe obstructive sleep apnea, at 25 percent, was higher than that for obese control subjects at 6.7 percent, or even patients with mild obstructive sleep apnea, who had 7.7 percent," study author Dr. Kenji Minoguchi, of Showa University School of Medicine in Tokyo, said in a prepared statement.
The researchers also found that elevated levels of inflammatory markers associated with cardiovascular disease can increase the risk of silent brain infarction.
In the study, they also examined the effects of three months of treatment with nasal continuous positive airway pressure (nCPAP) -- a device which reduces the number of episodes where a person stops breathing while sleeping. They tested the therapy on 24 men with moderate to severe obstructive sleep apnea.
The use of nCPAP significantly lowered levels of proteins associated with cardiovascular disease.
This shows that "nCPAP may be an important treatment intervention for decreasing the cerebrovascular risk in this susceptible population of obstructive sleep apnea patients," Minoguchi said.
The study is published in the second issue for March of the American Journal of Respiratory and Critical Care Medicine.
More information
The U.S. National Heart, Lung, and Blood Institute has more about sleep apnea.
