Endocrine Abstracts

Background: Calcium and vitamin D malabsorption in celiac disease (CD) predispose to high bone turnover and skeletal demineralization. Osteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, and ligand of receptor activator of NFkB (RANKL) inhibits osteoclast formation and activity.

The aim of this study was to evaluate the relationship between bone mineral density (BMD), bone-turnover markers and osteprotegerin in adult patients with CD and assess whether a gluten-free diet (GFD), calcium and vitamin D supplementation are sufficiently effective for BMD restoration.

Methods: BMD, calcemia, calciuria, and serum osteoprotegerin, Vitamin D, parathormone (PTH) and bone-turnover markers (ALP, osteocalcin, ICTP (C-terminal telopeptide of type I collagen)) concentrations were measured in 27adult CD patients and in 26 controls. Then the CD patients were treated with a GFD and calcium plus alfacalcidol for one year.

Results: Reduced BMD was diagnosed in 57–77% of the patients. Mean calcemia, calciuria, and 25(OH) Vitamin D were lower, but serum PTH and bone-turnover markers were significantly higher in CD patients than in controls. After one year of treatment, the biochemical abnormalities were considerably reduced, and BMD significantly increased (P<0.05), mostly in the lumbar spine.

Serum osteoprotegerin concentration was higher in CD patients than in controls before (P=0.001) and after (P=0.009) treatment. There was no correlation between OPG, PTH and bone turnover markers in CD patients. The negative correlation was observed only between OPG and osteocalcin in controls and in a group of CD patients after treatment. The slight negative correlation was found between OPG and spine BMD in whole examined group (P<0.05).

Conclusions: The OPG is involved in the process of bone turnover in celiac disease, but the mechanism is not clear. The elevation of OPG might be a compensatory mechanism against other factors that promote bone damage, but perhaps it is a part of inflammatory process in CD.