title: Bottle-feeding and the Risk of Pyloric Stenosis.
abstract: OBJECTIVE
  Bottle-feeding has been suggested to increase the risk of pyloric stenosis (PS). However, large population-based studies are needed. We examined the effect of bottle-feeding during the first 4 months after birth, by using detailed data about the timing of first exposure to bottle-feeding and extensive confounder information.
  
  
  METHODS
  We performed a large population-based cohort study based on the Danish National Birth Cohort, which provided information on infants and feeding practice. Information about surgery for PS was obtained from the Danish National Patient Register. The association between bottle-feeding and the risk of PS was evaluated by hazard ratios (HRs) estimated in a Cox regression model, adjusting for possible confounders.
  
  
  RESULTS
  Among 70148 singleton infants, 65 infants had surgery for PS, of which 29 were bottle-fed before PS diagnosis. The overall HR of PS for bottle-fed infants compared with not bottle-fed infants was 4.62 (95% confidence interval [CI]: 2.78-7.65). Among bottle-fed infants, risk increases were similar for infants both breast and bottle-fed (HR: 3.36 [95% CI: 1.60-7.03]), formerly breastfed (HR: 5.38 [95% CI: 2.88-10.06]), and never breastfed (HR: 6.32 [95% CI: 2.45-16.26]) (P = .76). The increased risk of PS among bottle-fed infants was observed even after 30 days since first exposure to bottle-feeding and did not vary with age at first exposure to bottle-feeding.
  
  
  CONCLUSIONS
  Bottle-fed infants experienced a 4.6-fold higher risk of PS compared with infants who were not bottle-fed. The result adds to the evidence supporting the advantage of exclusive breastfeeding in the first months after birth.
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, 5 Ørestads Boulevard, DK-2300 Copenhagen S, Denmark. ckr@ssi.dk
authors.forename: Camilla
authors.initials: C
authors.lastname: Krogh
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Biggar
authors.forename: Thea K
authors.initials: TK
authors.lastname: Fischer
authors.forename: Morten
authors.initials: M
authors.lastname: Lindholm
authors.forename: Jan
authors.initials: J
authors.lastname: Wohlfahrt
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
mesh_terms: D001903:Bottle Feeding / Q000009:adverse effects* / Q000706:statistics & numerical data; D001942:Breast Feeding / Q000706:statistics & numerical data; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D006306:Health Surveys; D006801:Humans; D007223:Infant; D008297:Male; D016016:Proportional Hazards Models; D046248:Pyloric Stenosis, Hypertrophic / Q000209:etiology* / Q000601:surgery; D012042:Registries; D012307:Risk Factors