Bone in coeliac disease

Abstract: Patients with untreated and treated coeliac disease were examined regarding bone mineral density (BMD) and biochemical factors of importance for bone metabolism. The occurrence of disturbances and their correction during treatment with a gluten-free diet were studied. BMD was measured in the forearm using single photon absorptiometry and in the hip and spine using dual-energy X-ray absorptiometry.Among the 288 adult patients with known coeliac disease in our catchment area, 13 patients with persistent villous atrophy of the proximal small bowel mucosa despite dietary recommendation were identified and compared with matched control-patients whose intestinal mucosa had normalised at least 4 years earlier. BMD was reduced in patients with persistent villous atrophy but within normal limits in patients responsive to the diet.In 105 adult patients with untreated coeliac disease, HN.ID was reduced compared to a local healthy control group. During the first year on a gluten-free diet the BMD increased rapidly (by a median of 3 %in the spine) even in patients with minor symptoms and in older patients. Secondary hyperparathyroidism was found in 27% of untreated patients and these patients had more severely reduced BMD compared to those with normal initial parathyroid hormone. Twenty-three % of the untreated patients also had low serum calcidiol (25-hydroxyvitarnin D) levels. BMD continued to increase in the second and third follow-up years, but only became normal within three years in the group of patients without initial secondary hyperparathyroidism.In 29 consecutive adult patients with untreated coeliac disease, serum insulin-like growth factor I and BMD were lower than in matched controls. In 14 untreated patients with normal parathyroid hormone values the increase in insulin-like growth factor I correlated positively to the increase in BMD during the first year after starting a gluten-free diet.In 46 adult patients with coeliac disease trt;atedfor 8-12 years in routine care, median BMD was normal but five patients who did not follow strict gluten-free diet had a lower BMD in the femoral neck than the group of 41 patients who claimed strict adherence.TI1ese studies show that untreated coeliac disease is associated with a low B:MD. BMD inereases rapidly when a gluten-free diet is followed, even in older patients. Circulating insulin-like growth factor I may reflect some changes in hone metabolism but its pathogenetic role behind the low BMD seen in adults with coeliac disease is unclear. Secondary hyperparathyroidism is common and vitamin D deficiency also seems to be an important underlying mechanism. These findings underline the importance of a gluten-free diet for all patients with coeliac disease.