The heritability of otitis media: a twin and triplet study.

CONTEXT Anatomical, physiological, and epidemiological data indicate that there may be a significant genetic component to prolonged time with and recurrent episodes of otitis media in children. OBJECTIVE To determine the genetic component of time with and episodes of middle ear effusion and acute otitis media (AOM) during the first 2 years of life. DESIGN Prospective twin and triplet cohort study with enrollment from 1982 through 1995. SETTING Otitis Media Research Center in the ear, nose, and throat clinic of Children's Hospital of Pittsburgh, Pittsburgh, Pa. PATIENTS A total of 168 healthy same-sex twin and 7 triplet sets were recruited within the first 2 months of life; zygosity results were available for 140 sets; 138 (99%) of these were followed up for 1 year and 126 (90%) for 2 years. MAIN OUTCOME MEASURES Proportion of time with middle ear effusion, episodes of middle ear effusion, and episodes of AOM by zygosity status. RESULTS At the 2-year end point, the estimate of heritability of time with middle ear effusion was 0.73 (P<.001). The estimates of discordance for 3 or more episodes of middle ear effusion were 0.04 for monozygotic twins and 0.37 for dizygotic twins (P = .01). The estimate of discordance of an episode of AOM in monozygotic twins was 0.04 compared with 0.49 in dizygotic twins (P = .005). CONCLUSIONS Our study suggests there is a strong genetic component to the amount of time with middle ear effusion and episodes of middle ear effusion and AOM in children.