title: Otitis media incidence and risk factors in a population-based birth cohort.
abstract: BACKGROUND
  Otitis media is the main reason young children receive antibiotics and is the leading reason for physician visits.
  
  
  OBJECTIVE
  To characterize the incidence, recurrence and risk factors for otitis media in a population-based birth cohort.
  
  
  METHODS
  All children born in southwestern British Columbia during 1999 to 2000 were followed until the age of three years. Otitis media was defined using The International Classification of Diseases, Ninth Revision coding of physician visits, and linked with antibiotic prescription data. Information on sex, birth weight, gestational age, Aboriginal status, maternal age, older siblings, maternal smoking during pregnancy, breastfeeding initiation, neighbourhood income, female education and rural residence were obtained from vital statistics, birth hospitalizations, perinatal registry and census data.
  
  
  RESULTS
  Complete risk factor information was available for 50,474 children (86% of all births). Nearly one-half of the children (48.6%) had one or more physician visits for otitis media during follow-up, and 3952 children (7.8%) met the definition for recurrent otitis media. Of the children with at least three visits during follow-up (n=7571), 73% had their initial visit during the first year of life. Aboriginal status, maternal age younger than 20 years, male sex and older siblings were the strongest risk factors identified in the adjusted conditional logistic regression models.
  
  
  CONCLUSIONS
  The present study established a population-based birth cohort by linking multiple administrative databases to characterize the incidence of and risk factors for otitis media. Although the incidence of otitis media is generally low in southwestern British Columbia, important risk factors continue to be young maternal age, mothers who smoke during pregnancy and children with Aboriginal ancestry.
authors: School of Environmental Health, University of British Columbia, Vancouver, British Columbia;
authors: Elaina A
authors: EA
authors: Macintyre
authors: Catherine J
authors: CJ
authors: Karr
authors: Mieke
authors: M
authors: Koehoorn
authors: Paul
authors: P
authors: Demers
authors: Lillian
authors: L
authors: Tamburic
authors: Cornel
authors: C
authors: Lencar
authors: Michael
authors: M
authors: Brauer