Elevated bone phosphorus/hydroxyproline ratio following jejunoileal bypass surgery.

The degree of bone mineralization, estimated as the bone phosphorus/hydroxyproline ratio (P/Hypro), was studied in 33 patients who had undergone jejunoileal bypass surgery for massive obesity. Low values of bone P/Hypro are expected in osteomalacia. We found an elevated mean bone P/Hypro (p < 0.001) with the highest values in patients with the longest postoperative periods (rS = 0.65, p < 0.001). The study indicates that bypass surgery, in spite of vitamin D deficiency, is associated with an increased average degree of bone mineralization or a defect in bone collagen synthesis.