title: Lack of seasonal variation in the incidence of eosinophilic oesophagitis in adolescent and adult non-PPI-responsive oesophageal eosinophilia midwestern US populations.
abstract: BACKGROUND
  Eosinophilic oesophagitis (EoO) has been associated with allergic disorders as well as aeroallergens. The current literature has shown a possible association between seasonal variation, mainly in the spring, and the incidence of EoO. However, this data was based on small population studies that did not exclude proton-pump inhibitor (PPI)-responsive oesophageal eosinophilia (PPI-ROE) in their cohort.
  
  
  OBJECTIVE
  The aim of this study was to determine if there is a seasonal variation associated with the diagnosis of EoO in patients that had been treated with high-dose PPI prior to diagnosis.
  
  
  METHODS
  Oesophageal biopsies were obtained from a cohort of patients who presented with symptoms of dysphagia, odynophagia, and heartburn during a 10-year period. Symptomatic patients who had biopsies from the mid and distal oesophagus with ≥20 eosinophils per high-power field (hpf) while on high-dose PPI treatment for at least 5 weeks were diagnosed as having EoO. The monthly and seasonal incidences were determined (winter, January-March; spring, April-June; summer, July-September; Autumn, October-December).
  
  
  RESULTS
  A total of 20,718 patients were identified and their records evaluated. From this cohort, 193 (0.93%) symptomatic patients had biopsy-proven oesophageal eosinophilia (≥20 eosinophils/hpf) and no seasonal variation was seen in this group. However, only 57 (0.28%) had been adequately treated with PPI prior to diagnosis (i.e. non-PPI-ROE biopsy-proven EoO; ≥20 eosinophils/hpf: 39 males, 18 females; age 29.5 years). The most common medical history components included asthma (12.3%) and food allergies (3.5%), and the most common presenting symptoms included dysphagia (50.9%) and heartburn (26.3%). The monthly and seasonal incidences in our cohort were with no apparent trend (p = 0.713 and 0.703, respectively).
  
  
  CONCLUSIONS
  The incidence of EoO was consistent across all 12 months as well as during the four seasons. Our data does not support a seasonal variation in relation to the incidence of EoO in the US midwestern non-PPI-ROE population.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Frederickson
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Levent
authors.initials: L
authors.lastname: Bayman
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Valestin
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Redd
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Ye-Jin
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Soubra
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Schey
keywords: Annual; PPI-responsive oesophageal eosinophilia; incidence; seasonal variation