In a study of 163 nondrinking patients evaluated in a sleep disorder clinic, researchers found that approximately 33% of those with severe obstructive sleep apnea (OSA) had elevated liver enzymes. Dr. Lawrence Serfaty of Hopital Saint-Antoine (Paris) who led the team stated that this finding suggested "a role for obstructive sleep disorder in liver injury independent of BMI (body mass index)."
The study also suggests that patients with elevated liver enzymes should be tested for OSA if no other causes for the liver problems are present. Insulin and insulin-resistance were also more frequent in patients with severe OSA as compared to those with moderate or no sleep apnea.
This study supports prior research which suggested that apnea may be an independent risk factor for liver problems notwithstanding the fact that the majority of patients with apnea were overweight and therefore already at increased risk of fatty liver disease. The data from these studies support the theory that liver damage may be due to the hypoxia induced by apnea and the apnea may be causing increased insulin resistance in patients with non-alcoholic steatohepatitis. It also means that apnea should always be investigated in patients who do not display other causes for their liver disease.