Osteoporosis. Computer artwork of a human female skeleton degenerating due to osteoporosis. At left is a normal skeleton. The degeneration, seen from left to right over time, is the loss of height and the backwards curvature (kyphosis) of the spine. Osteoporosis is a condition where loss of bone mass causes a reduction in the bone density. It is most common in woman after the menopause because they no longer produce the hormone oestrogen that helps to retain bone mass. The loss of height and kyphosis occur due to the spinal bones (vertebrae) collapsing as they weaken due to the osteoporotic loss of bone mass. .