title: Is delivery by cesarean section a risk factor for food allergy?
abstract: BACKGROUND
  Cesarean delivery might delay the colonization of the newborn intestine. A delayed or aberrant colonization process has been offered as an explanation for the increase in allergic diseases.
  
  
  OBJECTIVE
  The aim of this study was to examine whether cesarean delivery and the use of antibiotics were associated with subsequent food allergy.
  
  
  METHODS
  In a population-based birth cohort of 2803 children, information regarding mode of delivery, maternal or infant use of antibiotics, and information on potential confounders was obtained prospectively from parental reports and the Norwegian Birth Registry. Parentally perceived reactions to egg, fish, or nuts, as well as objectively confirmed reactions to egg at the age of 2 1/2 years, were chosen as outcomes.
  
  
  RESULTS
  Among children whose mothers were allergic, cesarean section was associated with a 7-fold increased risk of parentally perceived reactions to egg, fish, or nuts (odds ratio, 7.0; CI, 1.8-28; P =.005) and a 4-fold increased risk of confirmed egg allergy (odds ratio, 4.1; CI, 0.9-19; P =.08) in a logistic regression analysis, adjusting for pregnancy complications, birth weight, gestational length, and socioeconomic factors. Among children whose mothers were not allergic, the association was much weaker and not significant. Maternal or infant use of antibiotics was not associated with an increased risk of food allergy.
  
  
  CONCLUSIONS
  The results indicate that in predisposed children cesarean section might increase the risk of development of food allergy, which supports the theory that factors interfering with the colonization process might play a role in the development of food allergy.
authors.affiliation: Norwegian Institute of Public Health, Division of Epidemiology, Oslo, Norway.
authors.forename: Merete
authors.initials: M
authors.lastname: Eggesbø
authors.forename: Grete
authors.initials: G
authors.lastname: Botten
authors.forename: Hein
authors.initials: H
authors.lastname: Stigum
authors.forename: Per
authors.initials: P
authors.lastname: Nafstad
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000900:Anti-Bacterial Agents / Q000009:adverse effects; D002585:Cesarean Section / Q000009:adverse effects*; D015331:Cohort Studies; D004531:Eggs / Q000009:adverse effects; D005260:Female; D005399:Fishes; D005512:Food Hypersensitivity / Q000209:etiology* / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006801:Humans; D007231:Infant, Newborn; D009754:Nuts / Q000009:adverse effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012307:Risk Factors; D017747:Seafood / Q000009:adverse effects
chemical_list: D000900:Anti-Bacterial Agents