Late Calcium Metabolic Consequences of Jejuno-ileal Bypass.

Seventeen patients with previous jejuno-ileal bypass operation (JIB) for obesity were included in a follow-up study 11 to 19 years after JIB. Evaluation of calcium-parathyroid hormone axis was performed by a highly sensitive two-site IRMA assay for serum intact parathyroid hormone and serum ionized calcium. Evidence of a varying degree of secondary hyperparathyroidism was found. The observed hyperparathyroidism was of clinical significance in a subpopulation characterized by increased bone turnover and reduced bone mineral content. As a consequence, the calcium metabolism with special attention to the parathyroid function must be carefully monitored in JIB patients. Serum ionized calcium alone and vitamin D metabolites do not identify patients at risk of bone loss.