When the non-osteoporotic, osteopenia and osteoporosis patient groups were divided into those with and without previous fractures, there was no significant difference in the level of cathepsin Z mRNA between those with or without fracture for the non-osteoporotic control subjects (Fig. 3d) (95% CI = −0.254 to 0.306, P = 0.851, post-hoc Bonferroni correction) or for the osteopenia patients (95% CI = −0.086 to 0.184, P = 0.474, post-hoc Bonferroni correction), suggesting that cathepsin Z mRNA levels were not, per se, a consequence of the occurrence of the fracture in these groups. This evidence concerns the gene CTSZ and osteoporosis.