title: The relationship between otitis media with effusion and contact with other children in a british cohort studied from 8 months to 3 1/2 years. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood.
abstract: OBJECTIVE
  It is generally acknowledged that otitis media with effusion is more prevalent among children attending grouped day care. This study aimed to refine this by determining the relationships with the numbers of children at the place of day care, the age of the child and the number of siblings he/she had.
  
  
  METHODS
  ALSPAC (the Avon Longitudinal Study of Pregnancy and Childhood) is a population based longitudinal study starting early in pregnancy and following the children throughout their lives. Nested within this study, a randomly selected group of 1590 children, the Children in Focus, were invited to attend a clinic for hands on examinations. Tympanometry was carried out at ages 8, 12, 18, 25, 31, 37 and 43 months of age. Bilateral otitis media with effusion (OME) was identified if both ears showed a flat trace. Multi-level modelling with logistic regression adjusted for a number of social and environmental influences.
  
  
  RESULTS
  Of the 1590 children invited to the 8-month clinic, 300 (19%) were excluded from the analysis because of failure to attend or because of missing data. The analyses were based on 1290 children. The prevalence of bilateral OME decreased with age, from 24.6% at 8 months to 11.9% at 43 months. Children with older siblings and those attending day care with four or more other children were at an increased risk of OME. The adjusted odds ratios (AOR) were 1.52 (95% confidence interval [CI] = 1.23, 1.88) and 1.36 (95% CI = 1.02, 1.82), respectively. The risk associated with older siblings declined with age and by 3 years these children were no longer more likely to have OME than children with no older siblings. No such interaction with age was found for children in group day care and these children continued to be at an increased risk over the entire age period of the study. There was no increased risk associated with day care when no other children attended (AOR = 1.18, 95% CI = 0.88, 1.58) or when one to three others were present (AOR = 1.10, 95% CI = 0.85, 1.42). Although there was no relationship with the number of hours spent in day care, children who had started attending group care with four or more other children before 9 months of age did have an increased risk compared with children starting later AOR = 1.88, 95% CI = 1.12, 3.14.
  
  
  CONCLUSIONS
  These results provide evidence that early contact with other children increases the risk of OME and that children attending day care with four or more other children remain at an increased risk of OME at least until 31/2 years.
authors.affiliation: Unit of Paediatric and Perinatal Epidemiology, University of Bristol, Bristol, UK. cdewey@AMGEN.COM
authors.forename: C
authors.initials: C
authors.lastname: Dewey
authors.forename: E
authors.initials: E
authors.lastname: Midgeley
authors.forename: R
authors.initials: R
authors.lastname: Maw
mesh_terms: D000158:Acoustic Impedance Tests; D017677:Age Distribution; D002656:Child Day Care Centers / Q000706:statistics & numerical data*; D002675:Child, Preschool; D015331:Cohort Studies; D016001:Confidence Intervals; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D009679:Nuclear Family; D016017:Odds Ratio; D010034:Otitis Media with Effusion / Q000175:diagnosis / Q000453:epidemiology*; D011247:Pregnancy; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012494:Sampling Studies; D017678:Sex Distribution; D006113:United Kingdom / Q000453:epidemiology