In a study of 60 pediatric peritoneal dialysis patients with secondary hyperparathyroidism, doxercalciferol was as effective as calcitriol in controlling serum parathyroid hormone levels and suppressing bone formation rates, with sevelamer allowing for higher vitamin D doses, while both phosphate binders equally controlled serum phosphate levels, but calcium carbonate increased serum calcium, and FGF-23 levels rose over fourfold with both vitamin D treatments (Wesseling-Perry, et al., 2011). Here, FGF23 is linked to secondary hyperparathyroidism.