In childhood and early adulthood, bones store calcium faster than they release it, which contributes to growth. Around age 30, bones achieve peak mass. The rate of calcium storage slows to the rate of calcium release. Peak bone mass is usually retained throughout reproductive life. Thereafter, roughly in parallel with decreasing levels of reproductive hormones, bones release calcium faster than they store it, resulting in demineralization, weakening, and increased risk of fracture.
Some people lose calcium faster than others, and progress to osteoporosis.
Although many factors may adversely affect the balance of calcium storage and release throughout the life cycle, loss of reproductive hormones is the most important. After age 40, women lose reproductive hormones faster than men. On average, the loss of reproductive hormones occurs much faster in women than in men. For this reason, women experience faster demineralization and weakening of bone. Osteoporosis can be prevented.