Osteomalacia and celiac disease: response to 25-hydroxyvitamin D

Bone pain and extremely low bone mineral density due to severe vitamin D deficiency in celiac disease

CASE REPORT

A 29-year-old wheelchair-bound woman was presented to us by the gastroenterologist with suspected osteomalacia. She had lived in the Netherlands all her life and was born of Moroccan parents. Her medical history revealed iron deficiency, growth retardation, and celiac disease, for which she was put on a gluten-free diet. She had progressive bone pain since 2 years, difficulty with walking, and about 15 kg weight loss. She had a short stature, scoliosis, and pronounced kyphosis of the spine and poor condition of her teeth. Laboratory results showed hypocalcemia, an immeasurable serum 25-hydroxyvitamin D level, and elevated parathyroid hormone and alkaline phosphatase levels. Spinal radiographs showed unsharp, low contrast vertebrae. Bone mineral density measurement at the lumbar spine and hip showed a T-score of -6.0 and -6.5, respectively. A bone scintigraphy showed multiple hotspots in ribs, sternum, mandible, and long bones. A duodenal biopsy revealed villous atrophy (Marsh 3C) and positive antibodies against endomysium, transglutaminase, and gliadin, compatible with active celiac disease. A bone biopsy showed severe osteomalacia but normal bone volume. She was treated with calcium intravenously and later orally. Furthermore, she was treated with high oral doses of vitamin D and a gluten-free diet. After a few weeks of treatment, her bone pain decreased, and her muscle strength improved.

DISCUSSION

In this article, the pathophysiology and occurrence of osteomalacia as a complication of celiac disease are discussed. Low bone mineral density can point to osteomalacia as well as osteoporosis.

Inflammatory bowel diseases, celiac disease, and bone

The article summarizes the current knowledge on the pathogenesis, clinical aspects and treatment of bone problems in the major inflammatory bowel diseases (Crohn's disease and ulcerative colitis) and celiac disease. It presents the physiological relationship between intestine and bone as well as the alterations determined by disease-disrupted intestinal integrity. Two hypotheses about the pathogenetic mechanisms of bone metabolism derangements and bone loss are discussed: the classical one, that indicates calcium malabsorption as the main culprit, and the new one, that emphasizes the role of inflammation. The article summarizes the available epidemiological data about osteopenia/osteoporosis and fragility fractures in these chronic intestinal diseases and presents the state-of-the-art treatment options.

Bone in celiac disease

Chronic inflammation and malabsorption in celiac disease (CD) can cause bone metabolism alterations and bone mineral loss in children and adults. Bone status before and after gluten-free diet, epidemiology of fractures, and possible treatment options for CD-related osteoporosis are presented. Controversial aspects of this complication of CD are discussed. The relationship between bone derangements and celiac disease (CD) was recognized almost 50 years ago, but many questions are still open. We are now aware that osteoporosis is a relatively frequent atypical presentation of CD, especially in adults, and that undiagnosed CD can be the cause of osteoporosis and related fractures. Chronic inflammatory intestinal diseases, including CD, can affect bone and mineral metabolism because of alterations in both systemic and local regulatory factors. The pathogenetic processes are still controversial, but two main mechanisms seem to be involved: intestinal malabsorption and the presence of chronic inflammation. This review analyzes the published data on bone involvement in children, adolescents, and adults either before or after a gluten-free diet. Special attention is paid to the epidemiology of fractures in celiac patients, considering that fractures are a major complication of osteoporosis and an important problem in the management of a chronic disease like CD. The usefulness of screening osteoporotic patients systematically for CD is still an open question, but some rules can be given. Finally, the current treatment options for children and adults are discussed. Recommendations for future clinical research are proposed.

Influence of pattern of clinical presentation and of gluten-free diet on bone mass and metabolism in adult coeliac disease

Since no information is available on bone derangements in subclinical coeliac disease (CD), we evaluated bone mineral density (BMD, expressed as z score) at lumbar spine, by X-ray dual-photon absorptiometry, and serum indices of bone metabolism and remodeling in 14 subclinical or silent patients, 10 classical patients, and 15 healthy volunteers all on a gluten-containing diet. In the subclinical group, BMD at lumbar spine was significantly higher than in the classical group (-1.3 +/- 0.8, 73% vs. -2.6 +/- 0.6, 88%, respectively; p < 0.001), but significantly lower than in volunteers (+0.4 +/- 1.1, 104%; p < 0.001). Similar changes were observed in serum calcium, whereas, as regards parathyroid hormone, no significant difference was found between subclinical and classical patients. 25-vitamin D was significantly lower, and 1,25-vitamin D was significantly higher in subclinical and classical patients than in healthy volunteers. Indices of bone remodeling were higher in the subclinical and classical groups than in the volunteers, but lower in the subclinical than in classical patients. Eight subclinical and 8 classical patients were reexamined after a period of gluten-free diet (GFD), and in both groups BMD had significantly improved. Our results show that osteopenia is a frequent feature also in subclinical CD, although the extent of bone and mineral metabolism derangements is lower than in classical CD. GFD is able to normalize BMD in subclinical and to significantly improve it in classical patients.

Reversal of osteopenia with diet in adult coeliac disease

To evaluate the effects of a gluten free diet on bone mineral density in untreated adult patients with coeliac disease, 63 patients (17-79 years, 35 women) were examined at diagnosis and after one year taking a gluten free diet. Bone mineral density was measured in the forearm using single photo absorptiometry and in the lumbar spine, femoral neck, and trochanter using dual energy x ray absorptiometry. The values for each patient were compared with those of 25 healthy controls, matched for sex, age, and menopausal state. Before being given a gluten free diet bone mineral density in the total group was reduced at all sites (p < 0.001). Age adjusted bone mineral density was inversely correlated with age. During the first year taking a gluten free diet bone mineral density increased at all sites (p < 0.01). This was seen in patients of all ages and in patients who were without symptoms of malabsorption (weight loss or diarrhoea) before treatment. Low bone mineral density in patients with untreated coeliac disease increases rapidly when treatment with a gluten free diet is followed. These findings emphasise the importance of early diagnosis and treatment in all patients with coeliac disease.

Body composition and bone mineral density in untreated and treated patients with celiac disease

Body composition and bone mineral density (BMD) were studied by X-ray absorptiometry in 20 untreated and 12 treated women with celiac disease, as well as in 85 age-matched control women. Untreated patients had a significantly lower body weight, fat mass, lean tissue mass and BMD at the lumbar spine and total skeleton compared to controls (p < 0.001 for all parameters). Treated patients had also a significantly lower body weight (p < 0.01) fat mass (p < 0.05) and bone mineral density at lumbar spine and total skeleton (p < 0.05) compared with controls, but lean tissue mass was not diminished. However, treated patients had a significantly higher body weight, fat mass and BMD of the total skeleton compared with untreated celiac patients (p < 0.01 for all parameters). Serum alkaline phosphatase levels were increased in untreated patients but serum 250HD was normal. In conclusion, celiac disease causes a global and almost universal reduction of fat mass and BMD. The results of this cross-sectional study suggest that osteopenia does not seem to be completely restored by adequate treatment. Alteration of vitamin D metabolism was not the cause of osteopenia in the majority of patients.

Bone mineral density in coeliac disease

Patients with coeliac disease may have osteomalacia or osteoporosis, even in the absence of abdominal symptoms. Little is known about the effects of a gluten-free diet and villous restitution on the bone mineral density in adult patients with coeliac disease. Of the 288 patients with coeliac disease in our unit, 13 (5%) had persistent villous atrophy of the small bowel despite dietary recommendations over at least the previous 4 years. For each of these 13 patients, 1 or 2 controls with coeliac disease, matched for age, gender, menopausal state, and dermatitis herpetiformis, whose intestinal mucosa had normalized at least 4 years earlier, were identified (n = 17). Bone mineral density was measured in the forearm using single-photon absorptiometry and in the femoral neck and trochanter using dual-energy X-ray absorptiometry. Bone mineral density was reduced at all sites in patients with persistent villous atrophy compared with patients responsive to diet and healthy controls. Bone mineral density in patients responsive to diet did not differ from that in healthy controls. Persistent villous atrophy is associated with low bone mineral density, underlining the importance of keeping to a proper diet.