[AnriXuinriZ]

Extra intake of calcium aint gonna do shit if you have a medical condition preventing the absorption of Ca. Menopausal medcation is a little weird but i can see the logic in that brittle fractures are (arguably) the most common in post-menopausal ladies as osteoporosis becomes very common among this demographic. Osteoporosis is a condition whereby there is "less bone" than in a healthy patient; this is easily observed in cross sections of trabecular bone of patients; osteoporotic patients having significantly reduced number of trabeculae.
The brittleness also comes from a reduction in the amount of organic component in bone: collagen. Collagen gives bone its toughness and flexibility, whereas the mineral component gives it strength. Over the years our bones mineralise changing the ratios of organic : mineral in the bone. Young people have high organic content in their bone which is why youngsters seem to bounce off everything (or suffer bone deformation from over loading) whereas the old people (with stronger, more mineralised bone) are more likely to sustain a fracture / break of some kind.