Systematic literature review of modifiable risk factors for recurrent acute otitis media in childhood.

OBJECTIVE Review evidence about modifiable risk factors for recurrent acute otitis media. SOURCE OF DATA MEDLINE with no language restriction, from January 1966 to July 2005, using descriptors "acute otitis media/risk factors". Two hundred and fifty-seven articles were obtained. These included randomized clinical trials, cohorts, case-control and cross-sectional studies that contained analyses of modifiable risk factors for the development of recurrent acute otitis media as the main objective and with samples of individuals up to the age of 18 years. Except when relevant, the following were excluded: non-systematic reviews, reports of cases, series of cases, and medical society guidelines. SUMMARY OF DATA Nine risk factors linked to the host and eight linked to the environment were identified. Of the first group, allergy, craniofacial abnormalities, gastroesophageal reflux and the presence of adenoids were classified as modifiable. In the second category, upper airway infections, day care center attendance, presence of siblings/family size, passive smoking, breastfeeding and use of pacifiers were included. Afterwards, the risk factors were classified in accordance with levels of evidence. CONCLUSIONS The risk factors established for recurrent acute otitis media and capable of being modified were the use of pacifiers and care in daycare centers. The probable risk factors were privation of mother's milk, presence of siblings, craniofacial abnormalities, passive smoking and presence of adenoids. No modifiable factor was classified as unlikely. Among those that need further study are allergy, gastroesophageal reflux and passive smoking during gestation.