title: Risk factors in the aetiology of hiatus hernia: a meta-analysis.
abstract: OBJECTIVE
  Hiatus hernia (HH) is commonly associated with gastro-oesophageal reflux disease, particularly reflux oesophagitis and Barrett's oesophagus. HH may increase with age as a result of fibromuscular degeneration. Obesity increases intra-abdominal pressure and may increase the risk of HH. A meta-analysis was undertaken to assess the influence of risk factors for HH.
  
  
  METHODS
  Studies that included HH and potential aetiological factors (e.g. age, sex and BMI) as keywords were extracted from Medline. Studies and were required to define HH endoscopically and include unselected study populations. Data on a number of HH in relation to aetiological factors were extracted and a meta-analysis was performed, provided at least two suitable studies for each factor were available.
  
  
  RESULTS
  From 2953 abstracts, 29 studies contained information on HH in relation to age, sex and BMI. Seven studies provided data for meta-analysis of the effect of age and HH was associated with age above 50 years [odds ratio 2.17, 95% confidence interval (CI): 1.35-3.51, P=0.001, I2=97.3]. Four studies provided data for meta-analysis of the effect of obesity and HH was associated with BMI above 25 kg/m2 (odds ratio 1.93, 95% CI: 1.10-3.39, P=0.002, I2=80.5). Eighteen studies provided data for meta-analysis of the effect of sex and HH was more common among men (odds ratio 1.36, 95% CI: 1.10-1.68, P=0.005, I2=89.5). Publication bias was assessed by the Classic fail-safe N test and no significant evidence of publication bias was noted.
  
  
  CONCLUSIONS
  The prevalence of HH increases with age and increasing BMI and HH is more common among men.
authors.affiliation: Department of Gastroenterology, Sandwell General Hospital, West Bromwich, UK.
authors.forename: Shyam
authors.initials: S
authors.lastname: Menon
authors.forename: Nigel
authors.initials: N
authors.lastname: Trudgill
mesh_terms: D001471:Barrett Esophagus / Q000150:complications / Q000453:epidemiology; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000453:epidemiology*; D006551:Hernia, Hiatal / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015995:Prevalence; D012307:Risk Factors