Three years' follow-up of bone density in adult coeliac disease: Significance of secondary hyperparathyroidism

Background: The mechanisms of disturbances in bone mineral density (BMD) in coeliac disease are not completely understood. The aim of this prospective study was to investigate the possible significance of secondary hyperparat hyroidism (SHPT) with regard to BMD in patients with untreated coeliac dise ase. Method: One hundred and five adult patients with untreated coeliac dis ease were examined for BMD and serum parathyroid hormone (PTH) concentratio n. BMD in the hip, lumbar spine, and forearm were examined up to 3 years af ter the introduction of a gluten-free diet. Results: SHPT was found in 27% (28 of 105) of the patients. In patients with SHPT serum levels of 25-hydro xy-vitamin D were lower and those of alkaline phosphatase higher than in pa tients with normal PTH, but ionized serum calcium did not differ between th e two groups. BMD was more severely reduced in patients with SHPT. Although the BMD increment was more rapid in patients with than in those without SP TH, only in the latter group did mean BMD became normal after 1-3 years on a gluten-free diet (GFD). After 3 years on a GFD more th:ln half of the pat ients with initial SHPT still had low BMD in both the hip and the forearm. Furthermore, in patients: with SHPT the intestinal mucosa more often remain ed atrophic at the I-year follow-up, despite good compliance with the diet. Conclusions: Low BMD in patients with untreated coeliac disease is often a ssociated with SHPT. After 3 years on a GFD the BMD remains low only in pat ients with initial SHPT. We therefore suggest that PTH should be measured w hen the diagnosis of coeliac disease is made, as an indicator of more serio us intestinal disorder and complicating bone disease.