Nocturnal Gastroesophageal Reflux: Respiratory Symptoms and Obstructive Sleep Apnea

• Main Author: Emilsson, Össur Ingi
• Other Authors: Þórarinn Gíslason, Christer Janson, Læknadeild (HÍ), Faculty of Medicine (UI), Heilbrigðisvísindasvið (HÍ), School of Health Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Iceland, School of Health Sciences, Faculty of Medicine 2016
• Subjects: Vélindabakflæði; Kæfisvefn; Asma; Faraldsfræði; Nocturnal gastroesophageal reflux; Obstructive sleep apnea; Asthma; Epidemiology; Doktorsritgerðir; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/144

Introduction: Nocturnal gastroesophageal reflux (nGER) is associated with respiratory symptoms and sleep-disordered breathing (SDB), but a causal relationship has not been established. The aim of this project was to investigate the association between nGER and respiratory and SDB symptoms, as well as changes in lung function, sleep study and respiratory biomarkers. Methods: Participants in two European general population cohort studies were studied: The Burden of Obstructive Lung Disease (BOLD), and the European Community Respiratory Health Survey (ECRHS) parts one (I) and two (II). Additionally, participants with nGER in part three (III) of the ECRHS in Iceland were invited for further studies, and similarly as many paired controls. Subjects were identified as having nGER if they reported nocturnal heartburn or regurgitation. Respiratory and SDB symptoms were assessed by questionnaires, blood samples drawn and spirometries performed. Only the ECRHS III nGER subcohort underwent a home sleep study, and collected exhaled breath condensate (EBC) and particles in exhaled air (PEx) samples. A subgroup underwent a 24 hour esophageal impedance-pH measurement. Results: Asthma and bronchitis symptoms were more common among nGER subjects than controls, as were exacerbations of respiratory symptoms. SDB symptoms were more common among nGER subjects. Under a nine year follow-up, subjects with persistent nGER developed respiratory and SDB symptoms roughly twice as often as those without nGER. No consistent differences were found in lung function tests. Objectively measured snoring was more common among subjects with nGER. Pepsin, substance P and 8-isoprostane in EBC were higher among nGER subjects. Subjects with both nGER and nocturnal cough had increased substance P in EBC. Albumin and surfactant protein A in PEx were lower among nGER subjects. These findings were independent of BMI. Conclusion: In the general population, nGER is associated with respiratory and SDB symptoms. Having persistent nGER increases the risk of ...