[Incidence, air pollution and risk factors of acute otitis media in the first year of life: a prospective study]

Abstract

Background: Epidemiological studies of acute otitis media (AOM) are scarce and no prospective studies have been performed in Spain.

Objectives: To describe the incidence of AOM in the first year of life and its associated risk factors, with special focus on air pollution.

Methods: We performed a prospective cohort study of 229 newborn infants during the first year of life stratified by pollution zones, and followed-up by their pediatricians in their health center. AOM was defined on clinical grounds. A questionnaire on risk/protective factors included items on the following: sex, older siblings, smoking, breastfeeding, socioeconomic status, parental education and the mother's occupational status.

Results: The incidence of AOM episodes during the first year of life was 45 % and the proportion of children who experienced at least one episode was 32 %. Independent risk factors were male gender (aOR: 2.03; 95 % CI: 1.09-3.7) and living in a polluted area (aOR: 2.01; 95 % CI: 1.05-3.84). Independent protective factors were being born in spring (aOR: 0.41; 95 % CI: 0.19-0.88) and having a mother with at least primary school education (aOR: 0,53; 95 % CI: 0.24-1.15). Socioeconomic markers indicated a lower mean level among families whose children had at least one AOM episode.

Conclusions: Air pollution and low socioeconomic status are greater risk factors for AOM than having siblings or parents who smoke. A minimum educational level reduces the risk of AOM. The incidence of AOM could be reduced by modifying certain environmental factors.