title: The genetic component of middle ear disease in the first 5 years of life.
abstract: OBJECTIVE
  To determine the genetic component of time with middle ear effusion (MEE) and episodes of MEE and acute otitis media.
  
  
  METHODS
  Prospective twin/triplet cohort.
  
  
  METHODS
  Research center at a tertiary pediatric hospital.
  
  
  METHODS
  A total of 168 healthy same-sex twin and 7 same-sex triplet sets were recruited by age 2 months.
  
  
  METHODS
  Longitudinal assessment of middle ear status by pneumatic otoscopy and tympanometry at monthly evaluations, and at examinations during upper respiratory tract infections or symptoms of middle ear disease.
  
  
  METHODS
  Proportion of time with MEE and episodes of acute otitis media and MEE.
  
  
  RESULTS
  Of the 140 sets for which zygosity was obtained, 114 were followed up to age 3 years and 83 sets to age 5 years. The heritability estimate for proportion of time with MEE in the first 5 years of life was 0.72 (P<.001). The correlation of proportion of time with MEE between children within a set was significantly higher in monozygotic sets (0.65-0.77) than in dizygotic sets (0.31-0.39) for each year to age 3 years. In the fourth and fifth years of life, the correlations decreased in both monozygotic and dizygotic twin sets.
  
  
  CONCLUSIONS
  Findings for the first 2 years of follow-up have been previously published and indicate a strong genetic component to the proportion of time with MEE. In the present report, which details the entire 5-year follow-up, the effect of this component appears to attenuate after the third year but its cumulative effect remains significant after 5 years.
authors.affiliation: Department of Otolaryngology, University of Pittsburgh School of Medicine, PA 15213, USA. margaretha.casselbrant@chp.edu
authors.forename: Margaretha L
authors.initials: ML
authors.lastname: Casselbrant
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Mandel
authors.forename: Howard E
authors.initials: HE
authors.lastname: Rockette
authors.forename: Marcia
authors.initials: M
authors.lastname: Kurs-Lasky
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Fall
authors.forename: Charles D
authors.initials: CD
authors.lastname: Bluestone
authors.forename: Robert E
authors.initials: RE
authors.lastname: Ferrell
mesh_terms: D000158:Acoustic Impedance Tests; D000208:Acute Disease; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D010033:Otitis Media / Q000235:genetics*; D010034:Otitis Media with Effusion / Q000235:genetics*; D038781:Otoscopy; D011446:Prospective Studies; D013997:Time Factors; D014310:Triplets; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic