Bone is an active, self-renewing tissue, constantly undergoing cycles of resorption to break down older bones, and building to add new bone tissue. With conditions associated with bone loss such as osteoporosis, bone resportption occurs to a greater extent compared to building, eventually leading to low bone mineral density and more fragile bones. A decrease in the ratio of biomarkers for bone builing relative to bone resorption in an indicator for conditions that favor bone loss.