title: First evidence of a possible association between gastric acid suppression during pregnancy and childhood asthma: a population-based register study.
abstract: BACKGROUND
  Recent data in mice suggest that acid suppression during pregnancy yields offspring with type 2 T helper-dominant immunity, suggesting a predisposition for allergy.
  
  
  OBJECTIVE
  To determine the association of in utero exposure to acid-suppressive medications and the subsequent development of allergic diseases in children.
  
  
  METHODS
  We studied a population-based observational cohort formed by linking data from three Swedish national healthcare registers: the Medical Birth Register, the Hospital Discharge Register, and the Swedish Prescribed Drug Register. Main outcome measures included a hospital discharge diagnosis of an allergic disease or prescription for asthma medications, epinephrine auto-injectors, antihistamines or steroid ointments in children. Data were analysed using the Mantel-Haenszel procedure.
  
  
  RESULTS
  Twenty-nine thousand four hundred and ninety (5.03%) children had a discharge diagnosis of allergy or prescriptions for allergy medications. Five thousand six hundred and forty-five (0.96%) children had been exposed to acid suppression therapy during pregnancy; of these, 405 (0.07%) were treated for allergic diseases. Exposure to acid-suppressive medications in utero was associated with an increased odds ratio (OR) for developing allergy (OR 1.43, 95% confidence interval (95% CI) 1.29-1.59). We observed this association irrespective of the type of drug, time of exposure during pregnancy, and maternal history of allergy. The use of maternal acid-suppressive medication was associated with an increased OR for the development of childhood asthma (3.7% in the population at large vs. 5.6% in exposed children, OR 1.51, 95% CI 1.35-1.69), but not for other allergic diseases.
  
  
  CONCLUSIONS
  These data provide first evidence of a significant association between in utero exposure to acid-suppressive drugs and the risk of developing childhood asthma.
authors.affiliation: Division of Gastroenterology and Nutrition, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: E
authors.initials: E
authors.lastname: Dehlink
authors.forename: E
authors.initials: E
authors.lastname: Yen
authors.forename: A M
authors.initials: AM
authors.lastname: Leichtner
authors.forename: E J
authors.initials: EJ
authors.lastname: Hait
authors.forename: E
authors.initials: E
authors.lastname: Fiebiger
mesh_terms: D000863:Antacids / Q000009:adverse effects* / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D000897:Anti-Ulcer Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006635:Histamine H2 Antagonists / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D008499:Medical Records; D016017:Odds Ratio; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D054328:Proton Pump Inhibitors / Q000009:adverse effects / Q000627:therapeutic use; D012042:Registries; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology
chemical_list: D000863:Antacids; D018927:Anti-Asthmatic Agents; D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors