Rupp T, et al. - Among 82 patients with osteoporosis (DXA T-score ≤ − 2.5 at the lumbar spine or total hip), researchers studied the relationships between c-terminal fibroblast growth factor 23 (FGF23) levels and laboratory markers of bone metabolism and bone microarchitecture. In patients with osteoporosis, high levels of FGF23 are associated with impaired trabecular (but not cortical) bone microarchitecture, and this association appears to occur after adjustment for confounding variables, including phosphate and vitamin D.