title: Seasonal variation in onset and relapse of IBD and a model to predict the frequency of onset, relapse, and severity of IBD based on artificial neural network.
abstract: BACKGROUND
  Previous research has yielded conflicting data as to whether the natural history of inflammatory bowel disease follows a seasonal pattern. The purpose of this study was (1) to determine whether the frequency of onset and relapse of inflammatory bowel disease follows a seasonal pattern and (2) to establish a model to predict the frequency of onset, relapse, and severity of inflammatory bowel disease (IBD) with meteorological data based on artificial neural network (ANN).
  
  
  METHODS
  Patients with diagnosis of ulcerative colitis (UC) or Crohn's disease (CD) between 2003 and 2011 were investigated according to the occurrence of onset and flares of symptoms. The expected onset or relapse was calculated on a monthly basis over the study period. For artificial neural network (ANN), patients from 2003 to 2010 were assigned as training cohort and patients in 2011 were assigned as validation cohort. Mean square error (MSE) and mean absolute percentage error (MAPE) were used to evaluate the predictive accuracy.
  
  
  RESULTS
  We found no seasonal pattern of onset (P = 0.248) and relapse (P = 0.394) among UC patients. But, the onset (P = 0.015) and relapse (P = 0.004) of CD were associated with seasonal pattern, with a peak in July and August. ANN had average accuracy to predict the frequency of onset (MSE = 0.076, MAPE = 37.58%) and severity of IBD (MSE = 0.065, MAPE = 42.15%) but high accuracy in predicting the frequency of relapse of IBD (MSE = 0.009, MAPE = 17.1%).
  
  
  CONCLUSIONS
  The frequency of onset and relapse in IBD showed seasonality only in CD, with a peak in July and August, but not in UC. ANN may have its value in predicting the frequency of relapse among patients with IBD.
authors.affiliation: State Key Laboratory for Oncogenes and Related Genes, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Division of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Cancer Institute, Shanghai Institute of Digestive Disease, Shanghai Jiao Tong University, 145 Middle Shandong Road, Shanghai, 200001, China.
authors.forename: Jiang Chen
authors.initials: JC
authors.lastname: Peng
authors.forename: Zhi Hua
authors.initials: ZH
authors.lastname: Ran
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
mesh_terms: D000328:Adult; D003093:Colitis, Ulcerative / Q000453:epidemiology*; D003424:Crohn Disease / Q000453:epidemiology*; D005260:Female; D005544:Forecasting / Q000379:methods; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016571:Neural Networks, Computer; D012008:Recurrence; D012621:Seasons; D012720:Severity of Illness Index; D014887:Weather