Statistics
Data management and statistical analyses were performed using IBM SPSS Statistics version 26 for macOS. For comparison of groups the chi-square test (χ²) was used. The p-value of significance was <0.05.
Results
The follow-up rate of group A was 85% at 15 and 26 years. The follow-up rate of group B was 78% at 15 years and 70% at 26 years. Nissen et al. has tested the differences in distribution, to examine whether the group with incomplete follow-up differed from the group with complete follow-up of the subjects in group B (7). The only significant difference (p < 0.05) was found in a higher prevalence of eczema (17%) amongst the infants with full follow-up compared to the group with incomplete follow-up (7%) (7).
During the first year of life, 117 infants (6.7%) of the birth cohort of 1,749 infants had symptoms suggestive of CMPA. Based on strict elimination/milk-challenge procedures in a hospital setting, the diagnosis of CMPA was confirmed in 39 infants, giving a 1-year incidence of 2.2% (95% CI: 1.5-2.9). Of the 39 infants with CMPA, 21 had IgE-mediated CMPA (positive skin-prick test and/or radioallergosorbent test (RAST) of 􏰀class 2 to cow’s milk protein) and 18 non-IgE-mediated CMPA. Symptoms of CMPA consisted of cutaneous symptoms (64%), gastrointestinal symptoms (59%) and respiratory symptoms (33%). 36/39 (92%) had more than one symptom (3, 6).
Table 1 presents the total recovery rates of CMPA from 1 to 26 years of age. There was full follow-up of the subject with persisting CMPA at 15 and 26 years.
At 15 years of age the prevalence of AA and RC was significantly higher (p = 0.017 and 0.002, respectively) amongst children with IgE-mediated CMPA compared to children with non-IgE-mediated CMPA. At 26 years of age, children with IgE-mediated CMPA had a significantly higher prevalence of AA (p = 0.002) compared to children with non-IgE-mediated CMPA. There was not observed any significant difference between children with IgE-mediated CMPA and children with non-IgE-mediated CMPA at either age regarding AD.
The prevalence of atopic diseases at 15 and 26 years amongst children diagnosed with CMPA during their first year of life (group A) and children from the unselected group of infants (group B) are presented in table 2.
The development of AA, RC and adverse reactions to other foods until 10 years of age has previously been reported in full (1, 6).
Discussion
This study describes the recovery rate of CMPA until 26 years of age and the prevalence of atopic diseases at 15 and 26 years of age in a birth cohort from 1985. Furthermore, it highlights the significant (p<0.05) differences in development of atopic diseases in a group of children with CMPA compared to a sample of unselected children from the same birth cohort.