,21,23,25,29–32 We therefore conducted a case–control study of youth with DMD on chronic GCs with and without osteoporosis to determine if there was an association between factors isolated from serum (PDGF-BB, VEGF, and angiogenin) and PBMC subpopulations (POCs, SPCs, and CD34+) cells) with subsequent fractures. Here, CD34 is linked to osteoporosis.