To Learn How Bone Structure and Bone Mass Change After Long-term PPI Use

Proton pump inhibitors (PPIs) are among the most widely used medications. It is becoming increasingly common for patients to take these potent acid suppressants on a long-term and continuous basis for erosive esophagitis, Barrett's esophagus and protection against nonsteroidal anti-inflammatory drug-related gastropathy. PPI therapy leads to elevated serum gastrin levels and may impair the absorption of calcium and food-bound vitamin B12. PPI-induced hypergastrinemia has a direct trophic effect on the parathyroid glands, leading to parathyroid hyperplasia, increased parathyroid hormone secretion and bone loss. Furthermore, both calcium malabsorption and vitamin B12 deficiency are associated with reduced bone mineral density (BMD) and increased osteoporotic fracture risk. Consistent with these data, recent studies revealed a positive association between PPI therapy and the risk of osteoporotic fractures. Peripheral quantitative computed tomography (pQCT) can provide a three-dimensional structural analysis of trabecular and cortical volumetric BMD (vBMD) and dimensions. These data are imperative for a valid assessment of the effect of chronic PPI therapy on bone strength. The investigators hypothesize that PPI therapy leads to decreased cortical and trabecular vBMD, cortical dimensions and bone strength.