Background: Patients with sleep disturbances have gastrointestinal symptoms. Breath hydrogen (H2) and methane (CH4) indicating small intestinal bacterial overgrowth (SIBO) might be related with these symptoms. The study was conducted to assess the link between breath profiles and untreated obstructive sleep apnea (OSA).
Methods: : This prospective study enrolled consecutive patients with OSA using polysomnography. Heart rate variability (HRV) was used as a measurement for the balance of autonomic nervous system during polysomnography. Glucose breath test (GBT) to evaluate breath H2 and CH4 and bowel symptom questionnaire to investigate associated intestinal symptoms were performed.
Results: Among 52 patients with OSA, 16 (30.8%) showed positivity to GBT. Although no significant difference was shown in GBT positivity between patients with healthy controls and patients with OSA (13.3% vs 30.8%, P = 0.109), breath H2 and CH4 levels in the OSA group were significantly higher than those in controls (P < 0.05). Flatulence was significantly common in OSA groups with GBT positivity than those without GBT positivity. Multivariate analysis demonstrated that waist-to-hip ratio (odds ratio = 12.889; 95% confidence interval (CI): 1.257-132.200; P = 0.031) and low-to-high-frequency ratio of HRV (odds ratio = 1.476; 95% CI: 1.013-2.151, P = 0.042) are independently related to GBT positivity in patients with OSA.
Conclusion: : Elevated breath H2 or CH4 after glucose load might not be an uncommon finding in patients with untreated OSA. Abdominal obesity and autonomic imbalance dysfunction are significantly associated with GBT positivity in OSA patients. SIBO could be considered as target for therapeutic management in OSA patients.
Keywords: Glucose breath test; heart rate variability; obstructive sleep apnea; small intestinal bacterial overgrowth.