Thus, it is possible that our relatively small sample size limited our ability to detect true differences and an additional study with larger sample size, preferably a prospective cohort study should be pursued to confirm our findings and establish any other distinct relationships between the bone remodeling proteins in the OPG/RANKL/RANK axis and bone density in subjects with nephrolithiasis. This evidence concerns the gene TNFRSF11A and nephrolithiasis.