How should relative risk estimates for acute otitis media in children aged less than 2 years be perceived?

To determine how the effects of certain risk factors for acute otitis media (AOM) vary according to the values of other risk determinants, and thus to obtain risk estimates more applicable to individual children, the medical records of a random sample of 2,512 children in northern Finland were monitored for the disease for up to an average age of 22 months. Information on determinants of AOM was obtained from parental questionnaires. The risk of the first AOM episode and that of later episodes were modelled separately by logistic regression using time dependent values for some determinants, The odds ratio (OR) estimates for the alterable risk factors varied markedly over categories of other determinants as follows: nursery day care versus home care (OR from 1.1 to 3.0), parental smoking (OR from 0.9 to 1.5), and breast-feeding (OR from 0.5 to 1.0), Hence, to assess the significance of each risk factor for an individual child, the values for other relevant factors must be considered concurrently.