Bone health is determined by genetics and the environment. Throughout life, both internal (e.g., genetics and hormones) and external (e.g., exercise and diet) factors are continually modeling and remodeling bones. The remodeling occurs via a complex and carefully orchestrated interplay between bone resorption (bone breakdown) and bone deposition (bone formation). Bone mass, i. e., the amount of minerals in the bone, reflects the interplay between these two processes.
Most bone mass is accrued early in life, with peak bone mass achieved by the age of 30. In later life, bone remodeling continues, but more bone is generally lost than gained. However, this doesn’t mean bone health can’t improve at any age. In fact, it is estimated that most of the adult skeleton is replaced every ten years, and lifestyle choices can modify the strength and health of these “new” bones.