The Bone Turnover Cycle

Abstract

The bone turnover cycle is responsible for the maintenance of skeletal health and bone repair throughout the lifecourse, and is defined by the work of osteoblasts, which are responsible for bone formation, and osteoclasts, which stimulate bone resorption. Disruptions to the bone turnover cycle in middle or later life can lead to bone diseases characterized by bone loss, such as osteoporosis. Disequilibrium in osteoclast proliferation can lead to osteoporosis, meaning many anti-osteoporosis medications target these cells, as slowing bone resorption has been shown to effectively preserve bone mineral density and protect against fractures. Bone turnover markers found in serum and urine allow for less invasive, repeated measurement of the bone turnover cycle. These repeated measurements within individuals can provide information about both bone health at baseline and response to treatment, making bone turnover markers key tools in monitoring osteoporosis.