title: Seasonal variations in onset and exacerbation of inflammatory bowel diseases in children.
abstract: BACKGROUND
  Studies have suggested that inflammatory bowel diseases (IBD) follow a seasonal pattern with regard to their onset and exacerbations. The aim of this study is to determine if there is any seasonal pattern to the onset and exacerbation of IBD in the pediatric population and if the birth of children diagnosed with IBD follows a seasonal pattern.
  
  
  METHODS
  Patients between the ages of 1 and 21 years and with a diagnosis of IBD established between July 1992 and July 2012 were included. Their onset and exacerbations of IBD (year and season) were recorded. The birth dates of the patients were aggregated to determine whether a seasonal birth pattern existed amongst them.
  
  
  RESULTS
  A total of 170 children were included in this study; 34% of patients had their onset in the fall and 19% of them had their onset in the summer. The total number of documented exacerbations was 358 and the median number of exacerbations was two, with a range of 1-11. IBD exacerbations were generally uniformly distributed throughout the year. We did not observe any specific season where children with IBD tended to be born.
  
  
  CONCLUSIONS
  Our data suggests that the onset of symptoms of IBD tends to have a seasonal trend with the highest incidence in the fall. However, we did not observe any association between seasonality and exacerbations in the pediatric population. Moreover, there was no specific season in which children with IBD tended to be born in greater numbers.
authors.affiliation: Department of Pediatrics, St. John Providence Children's Hospital, Detroit, MI, 48236, USA. drrajmohan.d@gmail.com.
authors.forename: Rajmohan
authors.initials: R
authors.lastname: Dharmaraj
authors.affiliation: Department of Pediatrics, St. John Providence Children's Hospital, Detroit, MI, 48236, USA. ajaber@gmail.com.
authors.forename: Anas
authors.initials: A
authors.lastname: Jaber
authors.affiliation: Department of Pediatrics, St. John Providence Children's Hospital, Detroit, MI, 48236, USA. rarora@dmc.org.
authors.forename: Rajan
authors.initials: R
authors.lastname: Arora
authors.affiliation: Department of Biostatistics, St. John Providence Children's Hospital, Detroit, MI, 48236, USA. karen.hagglund@stjohn.org.
authors.forename: Karen
authors.initials: K
authors.lastname: Hagglund
authors.affiliation: Department of Pediatric Gastroenterology, St. John Providence Children's Hospital, Wayne State University School of Medicine, Detroit, MI, 48236, USA. hernando.lyons@stjohn.org.
authors.forename: Hernando
authors.initials: H
authors.lastname: Lyons
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology*; D008297:Male; D012621:Seasons; D055815:Young Adult