The survey of factors associated with the development of immune tolerance in children with cow’s milk allergy; a cross-sectional study in Gorgan, Iran

Introduction: Cow’s milk allergy (CMA) is a common complication and one of the most common food allergies in infants, and it is estimated that this disease affects 2-3% of children under five years old. Objectives: This study investigated the factors associated with developing immune tolerance in children with CMA in Gorgan. Patients and Methods: In this cross-sectional study, 50 children with CMA referred to the asthma and allergy clinic of Taleghani Hospital in Gorgan during 2019-2020 were investigated. Multiple logistic regression was applied to measure odds ratios (ORs) and 95% confidence intervals (CIs) of the associations between the selected factors and tolerance to cow’s milk. Results: The results suggested that factors including standard delivery (P=0.024, OR=4.03, 95% CI: 1.20-13.53) and breastfeeding in the first month of birth (P=0.003, OR=6.73, 95% CI:1.94-23.36), and gastrointestinal symptoms (P=0.026, OR=3.78, 95% CI: 1.17-12.19) were associated with immune tolerance to CMA. Younger age of starting complementary feeding (P<0.001, OR=0.070, 95% CI:0.02- 0.30), younger age of starting cow’s milk feeding (P=0.003, OR=0.520, 95% CI: 0.32-0.83), skin symptoms (P=0.012, OR=0.211, 95% CI: 0.06-0.71) and respiratory symptoms (P=0.013, OR=0.219, 95% CI:0.07- 0.72) were associated with allergy persistence. Conclusion: The findings of our study demonstrated natural childbirth, breastfeeding, and gastrointestinal symptoms, including bloody stools, are factors related to immune tolerance in children with CMA. The findings showed that decreasing the onset of complementary feeding, reducing the age of cow’s milk feeding, and clinical manifestations of respiratory and skin are associated with persistent CMA in children.