Effect of acute oral calcium load on serum PTH and bone resorption in young healthy subjects: an overnight study

摘要

Objective: To investigate the effects of a 400 mg acute oral calcium dose on PTH and bone resorption markers in a young, healthy population. Design: Fasting serum parathyroid hormone (PTH), C-telopeptides (CTX), total calcium (Ca), albumin and urinary calcium/ creatinine ratio (uCa/Cr) were measured on two separate days: one before and the other 10 h after oral administration of 400 mg calcium. Serum 25-hydroxy vitamin D (25-OHD) status was assessed at baseline. Dietary calcium intake was assessed using a food frequency questionnaire (FFQ). Subjects: A total of 32 healthy, young adults (17 female, 15 male; mean +/- s.e.m. age: 21 +/- 1 y) took part in this study. Their mean (s.e.m.) calcium intake was 1125 (+/- 56) mg/day. Intervention: Effervescent Sandocal(R) 400 tablets dissolved in water. Results: After the calcium challenge, mean Ca and uCa/Cr ratio increased significantly, and both PTH and CTX concentrations were significantly lower. Multiple regression analysis showed no relationship between the response to the 400mg load and previous dietary calcium intake ( as assessed by FFQ) or serum 25-OHD. Conclusion: We have shown that in a young, healthy population, 400mg oral calcium can inhibit bone resorption ( as measured by serum CTX) and PTH, and this appears to be independent of previous dietary calcium intake and vitamin D status. Sponsorship: None.