title: Determinants for gallstone formation - a new data cohort study and a systematic review with meta-analysis.
abstract: OBJECTIVE
  Only few determinants of gallstone formation have been identified in cohort studies. The aim was to identify further determinants for gallstones in a Danish cohort and to perform a meta-analysis of results from existing cohorts.
  
  
  METHODS
  Data from a cohort study was used. Gallstone incidence was assessed through repeated ultrasound examinations. Body mass index (BMI), blood pressure, self-rated health, lifestyle variables, blood lipids, and use of female sex hormones were measured at the baseline examination. Statistical analyses included logistic regression. Based on a prospective protocol, a systematic review of the literature was performed identifying all articles dealing with determinants of incident gallstones. Meta-analyses of comparable determinants were performed through fixed effect models.
  
  
  RESULTS
  Participants with no gallstones at baseline and with at least one re-examination were followed-up completely (mean 11.6 years, N = 2848). The overall cumulative incidence of gallstones was 0.60% per year. Independent positive determinants for incident gallstones were age, female sex, non-high density lipoprotein (non-HDL) cholesterol, and gallbladder polyps. In addition, BMI was positively associated in men. The systematic review additionally identified associations for comorbidities, parity, and dietary factors. Meta-analysis confirmed the significant associations for incident gallstones and age, female sex, BMI, and non-HDL cholesterol. No significant associations were found for blood pressure, smoking, alcohol consumption, HDL cholesterol, or triglycerides in meta-analyses.
  
  
  CONCLUSIONS
  Age, female sex, BMI, non-HDL cholesterol, and polyps are independent determinants for gallstone formation. Incident gallstones and the metabolic syndrome share common risk factors. More studies are needed for further exploration.
authors.affiliation: a Digestive Disease Center , Bispebjerg University Hospital , Copenhagen , Denmark ;|b Research Centre for Prevention and Health , Centre for Health , Capital Region , Denmark ;
authors.forename: Daniel Mønsted
authors.initials: DM
authors.lastname: Shabanzadeh
authors.affiliation: a Digestive Disease Center , Bispebjerg University Hospital , Copenhagen , Denmark ;|c Institute for Clinical Medicine, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark ;
authors.forename: Lars Tue
authors.initials: LT
authors.lastname: Sørensen
authors.affiliation: b Research Centre for Prevention and Health , Centre for Health , Capital Region , Denmark ;|d Department of Public Health, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark ;|e The Faculty of Medicine , Aalborg University , Aalborg , Denmark.
authors.forename: Torben
authors.initials: T
authors.lastname: Jørgensen
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002763:Cholecystectomy; D008076:Cholesterol, HDL / Q000097:blood; D003718:Denmark; D005260:Female; D042882:Gallstones / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008019:Life Style; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood; D014463:Ultrasonography
chemical_list: D008076:Cholesterol, HDL; D014280:Triglycerides
keywords: Cholelithiasis; cohort studies; epidemiology; follow-up studies; gallbladder diseases; longitudinal studies; ultrasonography