Familial and microbiological contribution to the otitis-prone condition

Abstract

Objective: Our group has an ongoing clinical research project investigating the immunology of the otitis-prone (OP) phenotype. In light of evidence that this condition arises from underlying immunological defects, we examined our sample population of stringently defined OP (sOP) children suffering 3 episodes of acute otitis media within 6 months or 4 within a year for a familial association with the sOP phenotype.

Methods: We analyzed the frequency of sOP within and between families and the nasopharyngeal (NP) otopathogen colonization patterns within and between families.

Results: The presence of sOP siblings significantly predicted that additional children in the same family would likewise become sOP, with an odds ratio of 3.7 (95% CI 0.77-15.2, 95% lower bound 0.95). We further present evidence for an environmental contribution to this effect by means of prolonged exposure to otopathogens within family units.

Conclusion: sOP children have a significant familial association. The tendency of siblings to share similar patterns of microbial NP colonization contributes to this association. Further research is necessary to determine whether and to what extent genetics are involved.

Keywords: Heritability; Microbiome; Otitis; Statistics.

Figure 1

Comparison of similarity of microbiological isolates between siblings and between unrelated children. Similarity index represents the fraction of bacterial species shared between children according to the number of days between clinic visits. Figure also compares duration of colonization in individual subjects with and without siblings. Solid lines depict means, dashed lines show 95% confidence intervals.