title: The relationship between the season of birth and early-onset food allergies in children.
abstract: BACKGROUND
  This study examined the relationship between the season of birth (SoB) and other factors with the development of FA.
  
  
  METHODS
  A multicenter, cross-sectional pilot study recruited 1197 patients with FA. The main study recruited 440 incident cases (FA group) definitively diagnosed as FA at 0-1 year of age. In both studies, the frequency of autumn-winter births (AWBs) in FA patients was compared to the regional control population. In the main study, we analyzed the differences in the SoB and other factors between patients in the FA group and those in the non-FA group (n = 332) in allergy clinics.
  
  
  RESULTS
  The pilot study showed that the frequency of AWB (57.6%) in the FA patients was significantly higher than that of the regional control population (50.4%, OR, 1.34; p < 0.001). The main study also showed the dominance of AWB (62.7%) in the FA group in comparison with that in the regional control population (50.2%, OR, 1.70; p < 0.001). Preterm birth (OR, 0.43; p = 0.027) and the presence of two or more elder siblings (OR, 0.27; p = 0.012) were significantly associated with a lower frequency of FA than those of non-FA. AWB (RR, 1.21; p = 0.020) and preterm birth (RR, 0.55; p = 0.017) were significantly associated with a number of trigger foods. The SoB effect was observed in FA patients irrespective of the presence of infantile eczema.
  
  
  CONCLUSIONS
  AWB was predominant in the patients with newly diagnosed food allergies.
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.|Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Kajiyo
authors.identifier: http://orcid.org/0000-0002-1079-1593
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.|Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Teruaki
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.|Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Sato
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Kemal
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Joon
authors.initials: J
authors.lastname: Nakata
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Sugiura
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kando
authors.affiliation: Department of Public Health, Aichi Medical University, Nagakute, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishiyama
authors.affiliation: Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Department of Allergy, Aichi Children's Health and Medical Center, Obu, Japan.
authors.forename: Komei
authors.initials: K
authors.lastname: Ito
mesh_terms: D017668:Age of Onset; D003430:Cross-Sectional Studies; D005260:Female; D005512:Food Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D010865:Pilot Projects; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons
keywords: food allergy; incident case; risk factor; season of birth