Genetic background and the risk of otitis media.

Objective: Otitis media is a multifactorial disease where genetic background may have an important role. For genome-wide association studies, it is important to understand the degree of heritability. The objective of this study was to estimate the heritability of recurrent acute otitis media and chronic otitis media with effusion.

Methods: Children operated because of recurrent or chronic otitis media at the Helsinki University Central Hospital, Finland, as well as their families were recruited during 2008-2009. A cohort of 2436 subjects was enrolled consisting of 1279 children and their parents. The study subjects answered a questionnaire concerning their otitis media history and treatment, as well as tobacco exposure, allergy and asthma history. Heritability estimates were calculated for recurrent acute, chronic and any episodes of otitis media using software especially designed for estimating heritability in family cohorts.

Results: Altogether 901 subjects suffered from recurrent otitis media and 559 from chronic otitis media with effusion. The heritability estimates in our cohort were 38.5% for recurrent (P=7.3 × 10(-9)), 22.1% for chronic (P=4.6 × 10(-3)) and 47.8% for any otitis media (P=1.5 × 10(-11)).

Conclusions: Our results demonstrate a moderately strong and statistically significant genetic component for both recurrent acute otitis media and chronic otitis media with effusion. These results highlight the importance of unraveling the genetic factors for otitis media that are still poorly known.