FGF23 and adrenal gland hyperfunction: Previous studies have shown that bone of patients using glucocorticoids is characterized by osteocyte apoptosis.19, 20 Also, in mice, glucocorticoid exposure induced osteocyte apoptosis.20, 21 This underlying mechanism is supported by the finding that in patients with endogenous hypercortisolism after treatment, an increased serum FGF23 was found, which is considered as an independent marker of well‐functioning osteocytes.22 Unfortunately, we were not able to measure FGF23 concentrations in our study samples.