title: Global patterns of seasonal variation in gastrointestinal diseases.
abstract: OBJECTIVE
  This study reviewed previous studies to explore the global patterns of seasonal variation in gastrointestinal diseases.
  
  
  METHODS
  A series of systematic literature reviews were undertaken to identify studies reporting seasonal and monthly data on clinical onset or relapse of gastrointestinal diseases (Acute pancreatitis, inflammatory bowel disease, Peptic ulcer diseases (PUD), gastroesophageal reflux disease, colon cancer and colonic diverticulitis). Thirty-two primary studies (published 1970-2012) from 17 countries were identified.
  
  
  RESULTS
  Upon review of the evidence, it appears that the seasonal peaks of PUD are most prominent in colder months while the peak of incidence rate of Crohn diseases in most of the countries subjects were found during the spring and summer seasons. Seasonal trend in the onset of acute pancreatitis exhibits a summer peak in some countries. There were no clearly seasonal peaks noted for the ulcerative colitis.
  
  
  CONCLUSIONS
  Future experimental and observational studies should consider how the environmental factors (infection, cold, air pollution etc.) or other triggers (dietary habit, alcohol consumption) promotes or hinders such diseases.
authors.affiliation: Department of Medicine, Knappschafts Krankenhaus, Ruhr-University, Bochum, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Fares
mesh_terms: D003110:Colonic Neoplasms / Q000453:epidemiology; D004066:Digestive System Diseases / Q000453:epidemiology*; D004239:Diverticulitis, Colonic / Q000453:epidemiology; D005764:Gastroesophageal Reflux / Q000453:epidemiology; D014943:Global Health; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology; D010195:Pancreatitis / Q000453:epidemiology; D010437:Peptic Ulcer / Q000453:epidemiology; D012621:Seasons