Normal parathyroid function with decreased bone mineral density in treated celiac disease

The Effect of a Gluten-Free Diet on Vitamin D Metabolism in Celiac Disease: The State of the Art

Celiac disease is a chronic autoimmune disorder involving the small intestine, characterized by villous atrophy, crypt hyperplasia and an increase in intraepithelial lymphocytes. Due to both calcium malabsorption and immune activation, a high prevalence of bone mass derangement is evident in this condition, regardless of the presence of overt malabsorption. Alterations of mineral metabolism are also frequently described, and in this review, the modifications of serum levels of vitamin D are analyzed, according to the available literature on this topic. In untreated patients, secondary hyperparathyroidism is responsible for the hyperconversion of 25-vitamin D into 1,25-vitamin D making mandatory the determination of serum levels of both vitamin metabolites to avoid a wrong diagnosis of vitamin D deficit. A gluten-free diet allows for a normalization of bone and mineral metabolism, reverting these abnormalities and raising some doubts on the need for vitamin supplementation in all the patients. Data available do not support this wide indication, and a complete evaluation of bone and mineral metabolism should be performed to select patients who need this therapeutic approach.

The value and significance of 25(OH) and 1,25(OH) vitamin D serum levels in adult coeliac patients: A review of the literature

Within the wide spectrum of symptoms and alteration of systems that characterizes CeD, several studies indicate a low-level of vitamin D, therefore recent guidelines suggest its evaluation at the time of diagnosis. This review examines the data from existing studies in which vitamin D has been assessed in CeD patients. Our review indicates that most of the studies on vitamin D in adult CeD report a 25 (OH) vitamin D deficiency at diagnosis that disappears when the patient goes on a gluten-free diet, independently of any supplementation. Instead, when the calcitriol, the active 1,25 (OH) vitamin D form, was evaluated, it resulted in the normal range at the time of CeD diagnosis. A strict and lifelong gluten-free diet can help recover vitamin D level without any supplementation.

Normal Bone Mineral Density Associates with Duodenal Mucosa Healing in Adult Patients with Celiac Disease on a Gluten-Free Diet

Impairment of bone mineral density (BMD) is frequent in celiac disease (CD) patients on a gluten-free diet (GFD). The normalization of intestinal mucosa is still difficult to predict. We aim to investigate the relationship between BMD and duodenal mucosa healing (DMH) in CD patients on a GFD. Sixty-four consecutive CD patients on a GFD were recruited. After a median period of a 6-year GFD (range 2–33 years), patients underwent repeat duodenal biopsy and dual-energy X-ray absorptiometry (DXA) scan. Twenty-four patients (38%) displayed normal and 40 (62%) low BMD, 47 (73%) DMH, and 17 (27%) duodenal mucosa lesions. All patients but one with normal BMD (23 of 24, 96%) showed DMH, while, among those with low BMD, 24 (60%) did and 16 (40%) did not. At multivariate analysis, being older (odds ratio (OR) 1.1, 95% confidence interval (CI) 1.03–1.18) and having diagnosis at an older age (OR 1.09, 95% CI 1.03–1.16) were associated with low BMD; in turn, having normal BMD was the only variable independently associated with DMH (OR 17.5, 95% CI 1.6–192). In older CD patients and with late onset disease, BMD recovery is not guaranteed, despite a GFD. A normal DXA scan identified CD patients with DMH; thus, it is a potential tool in planning endoscopic resampling.

Lower Limb Metaphyseal Bone Is Lost in Men with Coeliac Disease and Does Not Relate to Parathyroid Status

Aims. To investigate regional lower limb bone density and associations with weight, PTH, and bone breakdown in coeliac men. Methods. From whole body DXA scans bone mineral density (BMD) was measured in 28 coeliac men, in the lower limb (subdivided into 6 regions, 3 being metaphyseal (mainly trabecular) and 2 diaphyseal (mainly cortical)). BMD at femoral neck (FN) and lumbar spine L2-4, body weight, height, serum calcium, alkaline phosphatase, parathyroid hormone (PTH), and urinary calcium and NTx/Cr, a measure of bone breakdown, were also measured. Age matched healthy men provided values for BMD calculation of z and T scores and for biochemical measurements. Results. Low BMD z scores were found at metaphyseal regions in the leg (p < 0.001) and in the FN (p < 0.05). The distal metaphyseal region BMD in the leg was lower than spine or FN (p < 0.05). PTH, urinary calcium/creatinine, and urinary NTx/Cr were similar to controls. Both metaphyseal and diaphyseal BMD z scores were associated with body weight (p < 0.02), but not with either PTH or urinary NTx/Cr. Conclusions. Low BMD lower limb regions comprising mostly trabecular bone occur early in CD and in the absence of elevated PTH or increased bone resorption. Low BMD is associated with low body weight.

Bone mass and mineral metabolism alterations in adult celiac disease: pathophysiology and clinical approach

Osteoporosis affects many patients with celiac disease (CD), representing the consequence of calcium malabsorption and persistent activation of mucosal inflammation. A slight increase of fracture risk is evident in this condition, particularly in those with overt malabsorption and in postmenopausal state. The adoption of a correct gluten-free diet (GFD) improves bone derangement, but is not able to normalize bone mass in all the patients. Biomarkers effective in the prediction of bone response to gluten-free diet are not yet available and the indications of guidelines are still imperfect and debated. In this review, the pathophysiology of bone loss is correlated to clinical aspects, defining an alternative proposal of management for this condition.

Bone mineralization in celiac disease

Evidence indicates a well-established relationship between low bone mineral density (BMD) and celiac disease (CD), but data on the pathogenesis of bone derangement in this setting are still inconclusive. In patients with symptomatic CD, low BMD appears to be directly related to the intestinal malabsorption. Adherence to a strict gluten-free diet (GFD) will reverse the histological changes in the intestine and also the biochemical evidence of calcium malabsorption, resulting in rapid increase of BMD. Nevertheless, GFD improves BMD but does not normalize it in all patients, even after the recovery of intestinal mucosa. Other mechanisms of bone injury than calcium and vitamin D malabsorption are thought to be involved, such as proinflammatory cytokines, parathyroid function abnormalities, and misbalanced bone remodeling factors, most of all represented by the receptor activator of nuclear factor B/receptor activator of nuclear factor B-ligand/osteoprotegerin system. By means of dual-energy X-ray absorptiometry (DXA), it is now rapid and easy to obtain semiquantitative values of BMD. However, the question is still open about who and when submit to DXA evaluation in CD, in order to estimate risk of fractures. Furthermore, additional information on the role of nutritional supplements and alternative therapies is needed.

Role of Alendronate in Managing Osteoporosis in Celiac Disease - Illustrative Case Report

Management of bone density loss, as the result of calcium malabsorption in celiac disease, is critical in preventing premature bone fracture. As many of these patients need follow-up with primary care providers, internists are expected to be aware of screening and prompt management of osteopenia or osteoporosis in celiac disease. We present a case of a 32-year-old man with celiac disease who was diagnosed with osteoporosis. He was treated with calcium, vitamin D and alendronate which improved bone mineral density. This case illustrates the importance of using bisphosphonate in treating osteoporosis in celiac disease.

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.

Tissue transglutaminase antibodies in individuals with celiac disease bind to thyroid follicles and extracellular matrix and may contribute to thyroid dysfunction

BACKGROUND

Individuals with active celiac disease (CD+) have an increased incidence of thyroid dysfunction, which improves on a gluten-free diet (CD-). We investigated whether tissue transglutaminase-2 IgA antibodies (anti-TGase II) present in sera of patients with celiac disease react with thyroid tissue and possibly contribute to thyroid disease.

METHODS

Serum from 40 active celiac patients taken before a gluten-free diet (CD+), 46 patients on a gluten-free diet (CD-), 40 normal controls (NC), and 25 with Crohn's disease (CROHN) was used. All sera were screened for antithyroperoxidase antibodies (TPO-AB) and thyroglobulin antibodies (TG-AB), and indirect immunofluorescence (IIF) was performed on primate thyroid tissue sections using TPO-AB- and TG-AB-negative sera.

RESULTS

IIF with thyroid seronegative, anti-TGase II-positive CD+ sera (n = 23) demonstrated staining of thyroid follicular cells and extracellular matrix, in an identical pattern with monoclonal anti-human TGase II antibody. Evidence of TGase II as the antigen in thyroid tissue was supported by elimination of the IIF pattern when sera were depleted of anti-TGase II by pretreatment with human recombinant TGase II. No staining of thyroid tissue was observed when sera from CD+ patients that were negative for TGase II antibodies, or sera from NC subjects were used. Thyroid antibodies were found in 43% of CD+ patients, significantly higher than NC and CROHN patients (p < 0.0001). In addition, a positive correlation was observed between anti-TGase II and TPO-AB titers (p = 0.0001; r = 0.63).

CONCLUSIONS

Anti-TGase II antibodies bind to TGase II in thyroid tissue, and titers correlate with TPO antibody titers. These findings suggest that anti-TGase II antibodies could contribute to the development of thyroid disease in celiac disease.

Osteoporosis in celiac disease and in endocrine and reproductive disorders

As the increase in lifespan brings to light diseases that were previously not clinically detectable, osteoporosis has become an issue of worldwide significance. The disease is marked by a loss of bone mass; the bones become less dense, fragile and more prone to fracturing. Because it is regulated by endocrine and environmental factors, osteoporosis presents a multifactorial etiopathogenesis, with the genetic component accounting for 70% of an individual variation in bone mass density (BMD), the principal determinant, with age, of fracture risk. Pathological conditions such as celiac disease (CD) exacerbate the process of bone loss, so that the occurrence of osteoporosis in celiac subjects is of particular note: indeed, the screening of osteoporosis patients for this disease is advisable, since it may be the only sign of undiagnosed CD. An increase in interleukin IL-1β, of the IL-1 system, in the relatives of celiac patients confirms the genetic predisposition to osteoporosis and its presence is evidence of an association between the two conditions. The direct effect on the bones of CD is secondary to poor absorption of calcium and vitamin D. In women osteoporosis is indirectly associated with early menopause and amenorrhea, and it may follow prolonged breast-feeding and frequent pregnancies, while in men it is associated with hypogonadism and GH deficit. These endocrine and non-endocrine factors exert their effects on bones by modulating the RANK/RANK-L/OPG system. An appropriate lifestyle from adolescence onwards, together with early diagnosis of and treatment for CD and primary and secondary endocrine pathologies are important for the prevention of damage to the bones.

Case-finding for adult celiac disease in patients with reduced bone mineral density

The aim of this study was to assess the value of case-finding for unrecognized adult celiac disease (CD) in patients with reduced bone mineral density (BMD), verified by dual-energy X-ray absorptiometry (DXA). Patients attending for a DXA scan were investigated for CD using immunoglobulins, IgG/IgA antigliadin antibodies (AGA), and endomysial antibodies (EMA). All patients with a positive IgA AGA, EMA, or only IgG AGA in the presence of IgA deficiency had a small bowel biopsy. There were 12 cases of CD (12/978), a prevalence of 1.2% for the whole cohort. The prevalence of CD was 0.7% (2/304) for those with a normal BMD, 1.2% (5/431) for patients with osteopenia, and 2.1% (5/243) for patients with osteoporosis. Direct questioning revealed that all patients with unrecognized CD had subtle gastrointestinal symptoms or a history of anemia. Excluding patients without these symptoms would give a prevalence of 3.9% for osteoporosis (5/127) and 2.6% for osteopenia (5/191 ). This study suggests that there is no value of unselected case-finding for CD in patients with a reduced BMD. However, a targeted case-finding approach may be more valid and cost-effective with the initial selection of patients who should be investigated for CD based on questioning about gastrointestinal symptoms or anemia.

Management of osteoporosis in patients with gastrointestinal diseases

Osteoporosis is a frequent complication in the course of various gastrointestinal disorders. Since its pathogenesis is complex, and incompletely understood in comparison to the well-known pathomechanism of postmenopausal osteoporosis, adequate management is difficult. We first summarize those therapeutic options which have strong evidence in postmenopausal osteoporosis and, thereafter, we review those in the context of different gastrointestinal diseases. Treatment of the underlying intestinal disorder seems to be most important to normalise altered bone metabolism and to prevent osteoporosis in patients with coeliac disease. In patients with osteoporosis associated with Crohn's disease, various treatment strategies (such as vitamin D, sodium fluoride, bisphosphonates) are discussed. In contrast to postmenopausal osteoporosis, interventional studies in secondary osteoporosis are often limited by the small study population and data about the efficacy of any treatment in prevention of fractures are therefore lacking. Well-conducted, controlled studies with the endpoint of preventing fractures are therefore required to optimise the treatment of osteoporosis in these patients.