Mechanism of Gastroesophageal Reflux in Obstructive Sleep Apnea: Airway Obstruction or Obesity?

Abstract

Study Objectives: This is the first study to compare reflux events during wake and sleep in obese and non-obese individuals with obstructive sleep apnea (OSA) and obese individuals without OSA. The primary aim of the study was to investigate any additive effect of OSA on gastroesophageal reflux (GER) above that of obesity. Methods: Twenty obese individuals (body mass index, BMI > 30 kg/m 2 ), 9 non-obese individuals (BMI < 30 kg/m 2 ) with moderate-to-severe OSA, and 17 obese control subjects (BMI > 30 kg/m 2 ) underwent high-resolution esophageal manometry, 24-h esophageal pH-impedance monitoring, and in-laboratory polysomnography. Results: Mean body mass index was 40 ± 6 and 27 ± 4 kg/m 2 for the obese and non-obese OSA groups, respectively, and 34 ± 5 kg/m 2 for the obese control group. Apnea-hypopnea index (AHI) was 50 ± 30 and 30 ± 25 per hour for the obese and non-obese OSA groups (p > 0.05), significantly higher than that of the obese control group (3 ± 3 per hour, p < 0.05). The two obese groups did not show any significant differences in the total number of acidic reflux events (41 ± 20 vs 28 ± 16); however, the obese OSA group had a greater number of acidic reflux events compared to the non-obese OSA group (22 ± 12 events, p < 0.05). In multivariate analysis, BMI significantly predicted number of acidic reflux events (r 2 = 0.16, p = 0.01) during the 24-h period; however, AHI showed no significant association with any measure of GER severity. Conclusions: This study confirms an important role for obesity, rather than OSA per se in the relationship between OSA and GER.

Effect of CPAP Therapy on Symptoms of Nocturnal Gastroesophageal Reflux among Patients with Obstructive Sleep Apnea

“…[16][17][18] The most recent study by Shepherd and Orr reported such fi nding by documenting the nGER by esophageal pH monitoring during polysomnography and suggested that obesity rather than AHI may have a greater role in the relationship between OSA and nGER. 17 This prompted us to perform further subgroup analyses, which revealed that the BMI of our patients with moderate-severe OSA (mean = 34.17 kg/m 2 ) was much higher than those with mild OSA (mean = 28.98 kg/m 2 ). The total AHI revealed a linear positive association with nGER score among patients with moderate to severe OSA (AHI ≥ 15), but not among those with mild OSA (AHI < 15).…”

Gastroesophageal reflux disease: recent advances and its association with sleep

“…Obesity has an important role in the relationship between OSA and GER. 33 There was no relationship between the presence of GERD, OSArelated variables, and BMI in a study in Korea that used PSG and a questionnaire. 14 Ethnic differences between Eastern and Western populations should be considered.…”

“…A study using high‐resolution esophageal manometry, 24‐h esophageal pH–impedance monitoring, and PSG showed that BMI significantly predicted the number of acidic reflux events; however, the apnea–hypopnea index (AHI) did not exhibit any significant association with any measure of GER severity. Obesity has an important role in the relationship between OSA and GER . There was no relationship between the presence of GERD, OSA‐related variables, and BMI in a study in Korea that used PSG and a questionnaire .…”

Effect of continuous positive airway pressure on gastroesophageal reflux in patients with obstructive sleep apnea: a meta-analysis

“…The frequent co-occurrence of OSA and GERD may be explained by the following mechanisms. Firstly, GERD and OSA patients had similar risk factors: age, obesity, smoking, and alcohol consumption [8,9]. In addition, strong protective mechanisms for swallowing and esophageal peristalsis decline during sleep, which may delay esophageal acid clearance, thereby increasing acidmucosal contact time [10].…”