Propeptide of type I procollagen is predictive of posttreatment bone mass gain in adult celiac disease

Background & Aims: Adult celiac disease is associated with osteopenia, which is not always reversible after gluten-free diet (GFD). A prospective study was conducted to evaluate whether pretreatment indices of bone and mineral metabolism are predictive of the extent of bone mass gain after diet. Methods: Lumbar and femoral bone mineral density (z-score) and serum levels of parathyroid hormone, 1,25-dihydroxycholecalciferol, COOH-tevminal propeptide of type I procollagen (PICP), and COOH-terminal telopeptide of type I collagen (ICTP) were measured in 20 celiac patients at diagnosis and after 2 years of GFD. Results: All patients showed a posttreatment improvement in bone mass and in serum levels of indices of bone and mineral metabolism. Nevertheless, only in 12 of 20 patients was this improvement at least equal to half the SD of the z-score, which equals a gain of at least 5% in bone mass. Pretreatment levels of PICP strictly correlated with the increase in lumbar (r(s) = 0.92; P < 0.001) and femoral z-scores (r(s) = 0.89; P < 0.001). Only in patients with basal PICP above the normal range did the z-score increase after GFD by at least half the SD. Conclusions: In adult celiac disease, a high rate of osteosynthetic activity before treatment is predictive of the satisfactory recovery of bone mass after GFD.