Study objective: To estimate the possible association between reported symptoms of gastroesophageal reflux (GER) after bedtime, sleep-disordered breathing, respiratory symptoms, and asthma.
Design: Cross-sectional international population survey.
Participants: Participants consisted of 2,661 subjects (age range, 20 to 48 years) from three countries (Iceland, Belgium, and Sweden), of whom 2,202 were randomly selected from the general population and 459 were added because of reported asthma.
Measurements: The investigation included a structured interview, spirometry, methacholine challenge, peak flow diary, skin-prick tests, and a questionnaire on sleep disturbances.
Results: In the random population sample, 101 subjects (4.6%) reported GER, which was defined as the occurrence of heartburn or belching after going to bed at least once per week. Subjects with nocturnal GER more often were overweight and had symptoms of sleep-disordered breathing than participants not reporting GER. Participants with GER were more likely to report wheezing (adjusted odds ratio [OR], 2.5), breathlessness at rest (adjusted OR, 2.8), and nocturnal breathlessness (adjusted OR, 2.9), and they had increased peak flow variability compared to the subjects without GER. Physician-diagnosed current asthma was reported by 9% of subjects with GER compared to 4% of those not reporting GER (p < 0.05). Subjects with the combination of asthma and GER had a higher prevalence of nocturnal cough, morning phlegm, sleep-related symptoms, and higher peak flow variability than subjects with asthma alone.
Conclusion: The occurrence of GER after bedtime is strongly associated with both asthma and respiratory symptoms, as well as symptoms of obstructive sleep apnea syndrome. The partial narrowing or occlusion of the upper airway during sleep, followed by an increase in intrathoracic pressure, might predispose the patient to nocturnal GER and, consequently, to respiratory symptoms.