Assessing bone mineral changes in response to vitamin D supplementation using natural variability in stable isotopes of Calcium in Urine.

Osteoporosis is a chronic disease of public health importance, particularly in low and middle income countries. Measuring the bone mineral balance (BMB) in a non-invasive manner, and its response to different interventions, is critical to the definition of optimal strategies for its prevention and management. In this study, we demonstrate the usefulness of natural variability in calcium isotopes (δCa) of urine and the derived BMB estimates as a biomarker of bone health and its responsiveness to interventions. Vitamin D is commonly used as a supplement for the prevention and treatment of osteoporosis, along with calcium supplements. We studied the effect of a short term vitamin D supplementation on changes in urine δCa and the derived BMB. δCa before and after the vitamin D supplementation yielded a statistically significant change (p = 0.050) with a positive δCa enrichment. The mean derived BMB was net positive (0.04 ± 0.05) in comparison to a net negative value for the control group (-0.03 ± 0.01). These results indicate the potential usefulness of urinary natural δCa and the derived BMB, which, along with bone mineral density could be used as a sensitive marker for precision in the prevention and treatment of osteoporosis.