In the complex interaction between certain environmental factors and genetic disposition, the early allergen exposure plays a major role in the development of allergic diseases. In aiming to reduce the allergen burden for the infant at risk during early infancy, cow's milk protein hydrolysate infant formulas (hypoallergenic infant formulas) are appropriate alternatives to breastfeeding for primary allergy prevention. The German Infant Nutritional Intervention-Program (GINI) was supported for the first 3 years by the German Ministry for Education and Research (BMBF) (FKZ 01 EE 9401-4). It is a birth cohort which was primarily scheduled until the children were 3 years old. The aim of the prospective, randomized, double-blind intervention study was to investigate the impact of different cow's milk protein hydrolysate infant formulas in the first 4 - 6 months on the development of allergic diseases in children at risk due to at least one parent or biological sibling with a history of allergic disease. The allocation to one of the 4 intervention formulas (partial whey hydrolysate, extensive whey hydrolysate, extensive casein hydrolysate or standard cow's milk formula) was randomised and stratified by family history (single/biparental) and the respective obstetric clinic. Recruitment was carried out by the three clinical centers (Research Institute Marien-Hospital Wesel, Children's Department, Ludwigs-Maximilians-University Munich and Children's Department Technical University Munich) in 18 obstetric clinics between 01.09.1995 and 30.06.1998. Along with the intervention study a non-interventional, complementary observational cohort of children with or without allergy risk was recruited and followed by annual self-reporting parental questionnaires. The GINI intervention study (GINI-I, N = 2.252) and the non-interventional observation study (GINI-NI, N = 3.739) are combined in the population-based GINIplus study (see article J. Heinrich et al. in this journal). The results of the GINI intervention study confirm that, cow's milk protein hydrolysate infant formulas have a preventive effect on allergic manifestation compared with a standard cow's milk formula, until school age. However, the dimension of the effect is different between the formulas. This effect, which is mainly driven by the effect on atopic eczema, develops in the first months of life and persists without rebound. In the formula groups the cumulative incidence of atopic eczema until school age is reduced between 26% and 45% compared with standard cow's milk formula. A beneficial effect of the hydrolysate formulas on the respiratory manifestations asthma and rhinoconjunctivitis, however, could not be shown. By comparing the GINI intervention and non-intervention arm of the GINIplus study it was demonstrated, that a family history for allergy doubles the risk for eczema in the offspring. Early intervention with cow's milk protein hydrolysate infant formulas is able to substantially compensate this risk for eczema until the age of 6 years. In contrast, by randomization to standard cow's milk formula this risk showed a trend towards a higher incidence compared with children at risk from the non-intervention group. Thus, the results of the GINIplus study have contributed to answer some of the controversially discussed questions.
Keywords: birth cohort; double-blind, randomised intervention study; hypoallergenic infant formula; primary allergy prevention; prospective.