Bone remodeling is a process in which old, brittle bone tissue is resorbed or removed by osteoclasts and replaced by new, healthier bone tissue by osteoblasts. Bone remodeling helps adjust bone architecture and maintain structural integrity of the skeleton during the growth phase. Metabolically it contributes to the balance of calcium and phosphorus in the body. When peak bone mass is attained, bone remodeling remains stable for about one or two decades, after which bone loss starts. With increasing age, resorptive activity increases and bone formation decreases, leading to characteristic bone loss in aging individuals.