Predisposing factors for acute otitis media in infancy

Summary background: Factors predisposing to acute otitis media (AOM) are not thoroughly understood.

Objectives: In this study we prospectively investigated incidence rates and risk factors of AOM in a systematic sample of infants in a well-defined population.

Design and subjects: Following interview soon after delivery in a representative sample of 1049 mother-infant pairs, information was collected 1, 3, 6, 9 and 12 months after birth. Episodes of AOM were recorded as by parental reports of diagnosis made by a physician. AOM frequency was further analyzed against 21 social, maternal, paternal, prenatal, perinatal and infantile factors.

Results: Successful 12-month follow-up was achieved for 926/1049 infants (88.3%), of whom 265 (28.6%) were reported with episodes of AOM; 153 with a single, 55 with two, and 57 with three to six episodes (16.5%, 5.94%, and 6.16% respectively). Factors founded by multivariate analysis to predispose to AOM included presence of siblings (P<0.001), out-of-home daycare (P<0.001), ill health in pregnancy (P<0.01), and suboptimal breastfeeding (P<0.01). Multiple (3 or more) episodes were related to presence of siblings (P<0.0001), out-of-home daycare (P<0.001), ill health in pregnancy (P<0.001), and low parental education (P<0.001). 28 infants were hospitalized (10.6% of infants with AOM, 3.02% of the total cohort). Hospitalization was related to young maternal age (P<0.05).

Conclusions: Our findings confirm the high morbidity of AOM during infancy and point to several infant- and family-related predisposing factors, some of which are liable to intervention.