How does oestrogen influence bone turnover? The precise mechanism whereby oestrogen prevents bone loss is still uncertain. It has also been suggested that oestrogen controls bone resorption indirectly by regulating the secretion of calcitonin . Women have lower values of calcitonin than men and there is also an age related decline in secretion. Calcitonin exerts a bone conserving effect on the skeleton by inhibiting osteoclastic activity. Postmenopausally, loss of ovarian function hastens the age-related decline in calcitonin secretion, resulting in an increase in bone resorption. What are the typical osteoprotic fractures? Wrist or colles" fracture Crush fracture of thoracic and lumbar vertebrae Femoral neck How many women suffer wrist fracture? In women, the incidence of wrist fracture begins to rise around age 50 years and increases approximately 10 fold during the postmenopause. About 15% of women reaching age 75 years will have suffered a wrist fracture. There is no corresponding increase in wrist fracture incidence in men. How comon are vertebral crush fractures? This is the most common osteoporotic fracture. Approximately 15% of women aged 75 years have clinical evidence of this fracture, and a further 10% have radiological evidence. Thus, some fractures appear to be silent clinically and may be picked up accidentally when an X-ray is done for some other purpose. What are the effects? Significant collapse of one vertebral body usually leads to severe pain. In addition to repeated pain, numerous crush fractures result in loss of height and often a marked kyphosis. | 1 | 2 | 3 | 4 | 5 | MAIN PAGE