title: Relationship between body mass index and length of hospital stay for gallbladder disease.
abstract: BACKGROUND
  Obesity increases the risk of hospital admission for gallbladder disease but its impact on the length of hospital stay is largely unknown.
  
  
  METHODS
  Prospective population-based study of 1.3 million women aged 56 years on average, recruited from 1996 to 2001 in England and Scotland and followed-up through NHS hospital admission record databases for gallbladder disease (cholelithiasis, cholecystitis, cholecystectomy) over a total of 7.8 million person-years.
  
  
  RESULTS
  During follow-up, 24 953 women were admitted with gallbladder disease, 87% who had a cholecystectomy. After adjusting for age, socioeconomic status and other factors, women with higher BMI at recruitment to the study were more likely to be admitted and spend more days in hospital. For 1000 person-years of follow-up, women in BMI categories of 18.5-24.9, 25-29.9, 30-39.9, 40+ kg/m(2) spent, respectively, 16.5[16.0-17.0], 28.6[28.3-28.8], 44.0[43.4-44.5] and 49.4[45.7-53.0] days in hospital for gallbladder disease.
  
  
  CONCLUSIONS
  On the basis of these estimates, over a quarter of all the days in hospital for gallbladder disease in middle-aged women can be attributed to obesity.
authors.affiliation: CRUK Epidemiology Unit, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford OX3 7LF, UK. bette.liu@ceu.ox.ac.uk
authors.forename: Bette
authors.initials: B
authors.lastname: Liu
authors.forename: Angela
authors.initials: A
authors.lastname: Balkwill
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Spencer
authors.forename: Valerie
authors.initials: V
authors.lastname: Beral
mesh_terms: D015992:Body Mass Index; D002763:Cholecystectomy; D004739:England / Q000453:epidemiology; D005260:Female; D005705:Gallbladder Diseases / Q000150:complications* / Q000453:epidemiology / Q000601:surgery*; D006801:Humans; D007902:Length of Stay; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010343:Patient Admission; D011159:Population Surveillance; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012606:Scotland / Q000453:epidemiology