Although we observed differences in OPG/sRANKL ratio between the two groups (higher OPG/sRANKL ratio in breast-fed), but it was not statically meaningful.Known inducers of bone resorption and hypocalcaemia, such as IL1 and TNFα, act indirectly through the production of RANKL (19). This evidence concerns the gene TNFSF11 and Hypocalcemia.