Limitations and strenghts
It is difficult to avoid low follow-up rates in birth cohorts with long term follow-up. Yet in our study, the follow-up rate was considerably high at 85% for group A and 78% and 70% for group B, at 15 and 26 years, respectively. A limitation in our study was a small sample size. However, we have well defined sample of both infants with CMPA and a random sample of children from the same 1-year brth cohort. And all participants were followed closely and carefully in childhood up to 15 years of age and finally into adulthood at 26 years of age.
Participation in a cohort study may cause the participants to avoid possible risk factors due to increased awareness of allergic diseases, resulting in an underestimation of prevalence. Concurrently, an overestimation of prevalence amongst those with complete follow-up should be considered, since subjects with allergic diseases may be most motivated to participate in the study
We consider our data to have good validity and the results to be generalizable to the Danish population. All clinical investigations were performed or supervised by the same two pediatric allergologists (SH and AH) and included a rigorous methodology. We used predefined, generally accepted diagnostic criteria.
Conclusion
CMPA has a good prognosis regarding recovery rate. CMPA and sensitization in early childhood predict sensitization as well as development and often persistence of allergic diseases later in childhood and into adulthood. Children with CMPA exhibit a higher prevalence of asthma and rhinoconjunctivitis at 15 years of age, and at 26 years of age a higher prevalence of asthma and atopic dermatitis.