Effect of intermittent PTH treatment on plasma glucose in osteoporosis: A randomized trial

We investigated the effect of bone turnover on glucose homeostasis, fat distribution and adipokine production during anabolic treatment with PTH. This is a parallel, randomized controlled, open label, trial. The randomization was done by computer generated tables to allocate treatments. Forty-six postmenopausal osteoporotic non-diabetic women were assigned to treatment with calcium and colecalcipherol with (24) or without (22) PTH 1-84. Patients were recalled after 3, 6, 12 and 18 months of treatment and markers of bone turnover, glucose metabolism, adipokine secretion and fat distribution were analyzed. Markers of bone turnover and adipokines were measured by ELISA. Glucose metabolism was evaluated by an oral glucose load test and insulin resistance and secretion were calculated. Fat and lean mass were evaluated by anthropometric measures. The effect of treatment on measured variables was analyzed by repeated measure test, and its effect on glucose was also evaluated by mediation analysis after correction for possible confounders. Twenty patients in the calcium and vitamin D groups and 19 in the group treated with PTH 1-84 completed the study. There were no significance adverse events. Treatment with PTH increases osteocalcin, both total (OC) and undercarboxylated (uOC), and decreases blood glucose, without influence on insulin secretion, resistance and pancreatic β cell function. Treatment with PTH does not influence fat distribution and adipokine production. The results of the mediation analyses suggest a total effect of PTH on blood glucose, moderately mediated by OC and to a less extent by uOC. Here we suggest that treatment with PTH influences glucose metabolism partially through its effect on bone turnover, without influence on insulin secretion, resistance, pancreatic β cell function and fat mass.