title: Gastro-oesophageal reflux and respiratory symptoms in Busselton adults: the effects of bodyweight and sleep apnoea.
abstract: OBJECTIVE
  Respiratory symptoms and gastro-oesophageal reflux disease (GORD) are common within the general population. Although a number of epidemiological studies have addressed their relationship, none has investigated the confounding effects of body mass index (BMI) and obstructive sleep apnoea (OSA), both of which are associated with reflux.
  
  
  METHODS
  Men and women (2700) from the 2005-2007 cross-sectional Busselton health survey were included. Questionnaire data included demography, information on general health, asthma, cough, wheeze, dyspnoea and reflux symptoms (never, monthly or less often and weekly or more often). BMI, risk of OSA (Berlin questionnaire definition), spirometry and airway hyperresponsiveness (AHR) were recorded. The effects of BMI and OSA on the relationship between respiratory and reflux symptoms were examined using logistic regression models, expressed as adjusted odds ratios for risk of respiratory symptoms by reflux symptom category.
  
  
  RESULTS
  Fifty per cent had reflux symptoms (5-10% weekly or more often). Reflux symptoms had strong positive, dose-related associations with cough/phlegm, breathlessness, chest tightness and wheeze in the last 12 months (P < 0.001), but were not related to diagnosed asthma or AHR. Twenty-three per cent were at high risk of OSA and 63% had a BMI of >25 (22% > 30). Increased weight or high risk of OSA did not affect the relationship between respiratory symptoms and reflux symptoms.
  
  
  CONCLUSIONS
  The relationship between reflux and respiratory symptoms was independent of BMI, high risk of OSA or AHR. These findings suggest that reflux contributes directly to respiratory symptoms.
authors.affiliation: Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia. siobhain.mulrennan@health.wa.gov.au
authors.forename: S A
authors.initials: SA
authors.lastname: Mulrennan
authors.forename: M W
authors.initials: MW
authors.lastname: Knuiman
authors.forename: M L
authors.initials: ML
authors.lastname: Divitini
authors.forename: D J
authors.initials: DJ
authors.lastname: Cullen
authors.forename: M
authors.initials: M
authors.lastname: Hunter
authors.forename: J
authors.initials: J
authors.lastname: Hui
authors.forename: A W
authors.initials: AW
authors.lastname: Musk
authors.forename: A L
authors.initials: AL
authors.lastname: James
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012135:Respiratory Sounds / Q000503:physiopathology; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D014904:Western Australia / Q000453:epidemiology