Prospective cohort studies using hydrolysed formulas for allergy prevention in atopy-prone newborns: a systematic review

The aim of this study is to give a systematic overview on publications havi ng investigated the allergy preventive effect of extensively and/or partial ly hydrolysed infant formulas. Publications were searched by several strate gies. Inclusion criteria were: prospective cohort study, randomisation, fam ily history of atopy of the subjects, follow-up for at least the 1st year o f life. Studies were described systematically as to methods, study particip ants, interventions and co-interventions, and study outcomes. The methodolo gical quality was judged according to an instrument assessing the reduction of bias (score between 0 and 7 points). Data of studies having examined pa rtial hydrolysates are presented as odds ratios. Of 16 studies found, 10 fu lfilled the inclusion criteria. Study designs showed considerable differenc es as to methods, intervention and co-intervention procedures and definitio n of outcomes. Methodological quality varied between 0 and 6 points. The co mparison of exclusively test- and control formula-fed groups showed a unifo rm tendency towards allergy protection in studies with partial hydrolysates . Study results on the effect of extensive hydrolysates were not comparable because of major differences in study designs. Conclusion More well-designed studies with an adequate statistical power ar e needed to compare the allergy preventive effect of partially and extensiv ely hydrolysed formulas with a standard infant formula.