The impact of caesarean delivery and type of feeding on cow's milk allergy in infants and subsequent development of allergic march in childhood

The incidence of IgE-mediated cow's milk allergy (CMA) has increased over the last few years. There are several genetic and environmental risk factors that may be related to this allergy and the subsequent allergic march (AM). A prospective, cohort study was conducted in patients recruited into the study between 1998 and 2002. Information on clinical variables and complementary tests, perinatal and obstetric factors and the type of hydrolysed formula used was recorded. A cross sectional study on the prevalence of allergic diseases in this cohort was performed in 2004. We compared IgE-mediated CMA patients with non-IgE-mediated CMA patients and found that IgE-mediated CMA is associated with caesarean delivery (OR = 2.14 95% CI: 1.02-4.49), duration of breast feeding (> 2 months, OR = 4.14; 95% CI: 2.17-7.89) and the use of supplementary artificial formula whilst breast feeding (OR = 2.86; 95% CI: 1.33-6.13). The factors associated with AM in IgE-mediated CMA patients were caesarean delivery (OR = 0.42; 95% CI: 0.19-0.92) and the use of more extensively hydrolysed high grade hydrolysates (+EH/HGH) (OR = 0.44; 95% CI: 0.20-0.98), both as protective factors. Caesarean delivery is demonstrated as being a risk factor for IgE-mediated CMA, but it does not increase the risk of AM in these infants. The use of +EH/HGH appears to protect IgE-mediated CMA patients from eventually developing AM.