After the age of 75 hormonal influences are often overshadowed by other risks. Fractures represent submaximal accumulation of bone as a young adult or accelerated bone loss. During puberty, the growth spurts signal hormonal increases as well as bone remodeling. The growth plates begin to close and within 3 years of menarche, bone mass is nearly complete. Fifty to eighty percent of peek bone mass is genetically determined.
Bone loss occurs as a result of an imbalance between osteoblasts and osteoclasts.
This is a consistent process, where bone resorption is always followed by bone formation. This is called coupling. In postmenopausal women, the process is not balanced. There is an increase in the rate of new bone remodeling cycles and new bone formation cannot keep pace. Postmenopausal bone loss occurs in two phases.