Caption

X-ray (blue tint) of the knee in osteoporosis, showing patchy loss of bone density in the femur (thigh bone). A reduction in bone mass leads to increased brittleness & a risk of fractures, particularly of the vertebrae, hip or arm. The condition arises through an imbalance between formation & resorption of bone, most commonly occurring with increasing age. The incidence is greater in women than in men and is attributed to a decline in hormone production following the menopause. Oestrogens (sex hormones) may be used to prevent & treat age-related disease, although their use is controversial.