title: Chronic otitis media with effusion in infancy. How frequent is it? How does it develop?
abstract: OBJECTIVE
  To study the occurrence and development of chronic otitis media with effusion in infancy.
  
  
  METHODS
  A retrospective birth cohort with a 2-year follow-up. Infection data were gathered from medical records; background information came from questionnaires.
  
  
  METHODS
  Primary health care centers, hospitals, and private practices in 10 randomly selected local government districts in the two northernmost provinces of Finland.
  
  
  METHODS
  A random sample of 2512 children from the cohort.
  
  
  METHODS
  Chronic otitis media with effusion determined as a minimum of 2 months of asymptomatic middle ear effusion revealed by tympanocentesis and specific operative findings.
  
  
  RESULTS
  The periodic prevalence rate of chronic otitis media with effusion up to the age of 24 months was 4.4% (95% confidence interval, 3.5 to 5.3). The maximum risk was at age 16 months. The number of acute otitis media episodes among children who developed chronic otitis media with effusion was more than double that of normal healthy children before the onset of chronic inflammation and about five times as high during prolonged mucous middle ear effusion. Inadequate treatment of prior acute otitis media was not the reason for the chronic inflammation, which was a direct continuation of an acute episode in only half of the cases and was otherwise preceded by a latent period of varying duration.
  
  
  CONCLUSIONS
  Chronic otitis media with effusion, which may cause adverse developmental effects such as delayed language development, is a fairly common disease in infancy and is closely related to acute otitis media episodes.
authors.affiliation: Department of Otolaryngology, University of Oulu, Finland.
authors.forename: O P
authors.initials: OP
authors.lastname: Alho
authors.forename: H
authors.initials: H
authors.lastname: Oja
authors.forename: M
authors.initials: M
authors.lastname: Koivu
authors.forename: M
authors.initials: M
authors.lastname: Sorri
mesh_terms: D000208:Acute Disease; D017668:Age of Onset; D002908:Chronic Disease; D015331:Cohort Studies; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D010034:Otitis Media with Effusion / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D012189:Retrospective Studies; D012494:Sampling Studies