title: Respiratory symptoms and nocturnal gastroesophageal reflux: a population-based study of young adults in three European countries.
abstract: OBJECTIVE
  To estimate the possible association between reported symptoms of gastroesophageal reflux (GER) after bedtime, sleep-disordered breathing, respiratory symptoms, and asthma.
  
  
  METHODS
  Cross-sectional international population survey.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Lung Medicine, Vifilsstadir Hospital, Gardabaer, Iceland.
authors.forename: Thorarinn
authors.initials: T
authors.lastname: Gislason
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
authors.forename: Paul
authors.initials: P
authors.lastname: Vermeire
authors.forename: Peter
authors.initials: P
authors.lastname: Plaschke
authors.forename: Eythor
authors.initials: E
authors.lastname: Björnsson
authors.forename: David
authors.initials: D
authors.lastname: Gislason
authors.forename: Gunnar
authors.initials: G
authors.lastname: Boman
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D001530:Belgium; D015984:Causality; D015897:Comorbidity; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000453:epidemiology*; D006801:Humans; D007055:Iceland; D008297:Male; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000453:epidemiology* / Q000209:etiology; D013548:Sweden