title: Epidemiology of otitis media onset by six months of age.
abstract: OBJECTIVE
  Although early otitis media (OM) onset predicts later recurrent and chronic OM, little research has been directed at illuminating the role of prenatal exposures in early OM. This prospective study examined prenatal, innate, and early environmental exposures associated with acute otitis media (AOM) onset and recurrent OM (ROM) by age 6 months.
  
  
  METHODS
  Prospective study of 596 infants from a health maintenance organization followed from birth to 6 months. Mothers completed monthly forms on prenatal exposures (diet, medications, and illnesses) and infant risk factors (eg, smoke exposure and child care) during pregnancy and until infants were 6 months old. Urine samples were collected when infants were 2 months of age and analyzed for cotinine and creatinine. Physicians and nurse practitioners examined infants at each clinic visit and completed standard ear examination forms.
  
  
  RESULTS
  Thirty-nine percent had an episode of AOM and 20% had ROM by age 6 months. Using Cox's regression models to control for confounding, respiratory tract infection (relative risk [RR] 7.5), day care (RR 1. 7), >1 sibling (RR 1.4), maternal, paternal, and sibling OM history (RR 1.6, 1.5, and 1.7, respectively) were significantly related to early OM onset. ROM was related to respiratory tract infection (RR 9. 5), day care (RR 1.9), conjunctivitis (RR 2.0), maternal OM history (RR 1.9), and birth in the fall (RR 2.6). Among prenatal exposures, only high prenatal dietary vitamin C intake was significantly inversely related to early AOM with univariate but not multivariate analysis.
  
  
  CONCLUSIONS
  Prenatal factors were not linked to early AOM onset with multivariate analysis, but environmental and innate factors play an important role in early AOM onset. Strategies to reduce exposure to environmental variables could reduce rates of early AOM, which could potentially result in declining rates of ROM and chronic OME.
authors.affiliation: Otitis Media Research Center, University of Minnesota School of Medicine, Minneapolis, Minnesota, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Daly
authors.forename: J E
authors.initials: JE
authors.lastname: Brown
authors.forename: B R
authors.initials: BR
authors.lastname: Lindgren
authors.forename: M H
authors.initials: MH
authors.lastname: Meland
authors.forename: C T
authors.initials: CT
authors.lastname: Le
authors.forename: G S
authors.initials: GS
authors.lastname: Giebink
mesh_terms: D000208:Acute Disease; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002908:Chronic Disease; D003367:Cotinine / Q000652:urine; D003401:Creatine / Q000652:urine; D004777:Environment; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008423:Maternal Age; D018811:Maternal Exposure; D015999:Multivariate Analysis; D010033:Otitis Media / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D012008:Recurrence; D012141:Respiratory Tract Infections / Q000150:complications; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D000900:Anti-Bacterial Agents; D003367:Cotinine; D003401:Creatine