title: Physical Activity and the Risk of Gallbladder Disease: A Systematic Review and Meta-Analysis of Cohort Studies.
abstract: Physical activity has been hypothesized to reduce the risk of gallbladder disease (gallstones, cholecystitis, cholecystectomy); however, results from epidemiological studies have not always shown statistically significant associations. We conducted a systematic review and meta-analysis to clarify the presence and strength of an association between physical activity and gallbladder disease risk.
  
  
  
  PubMed and Embase databases were searched for studies of physical activity and gallbladder disease up to 9th of January 2015. Prospective studies reporting relative risk (RR) estimates and 95% confidence intervals (CIs) of gallbladder disease associated with physical activity were included. Summary RRs were estimated using a random effects model.
  
  
  
  Eight studies including 6958 cases and 218,204 participants were included. The summary RR for the highest versus the lowest level of physical activity was 0.75 (95% CI: 0.69-0.81, n = 8) and there was no evidence of heterogeneity, I2 = 0%). In the dose-response analysis the summary relative risk per 20 MET-hours of activity was 0.85 (95% CI: 0.80-0.90, I2 = 0%, n = 2) for leisure-time physical activity, 0.83 (95% CI: 0.76-0.90, I2 = 0%, n = 2) for vigorous physical activity, and 0.86 (95% CI: 0.76-0.98, I2 = 0%, n = 2) for nonvigorous physical activity.
  
  
  
  Our analysis confirms a protective effect of physical activity on risk of gallbladder disease.
authors.affiliation: Dept of Epidemiology and Biostatistics, Imperial College, St. Mary's Campus, London, UK.
authors.forename: Dagfinn
authors.initials: D
authors.lastname: Aune
authors.forename: Michael
authors.initials: M
authors.lastname: Leitzmann
authors.forename: Lars Johan
authors.initials: LJ
authors.lastname: Vatten
mesh_terms: D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D005705:Gallbladder Diseases / Q000209:etiology*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors