Why is it considered important? Postmenopausal osteoporosis is a serious, yet preventable, clinical problem affecting large number of women and resulting in significant morbidity and mortality. By around age of 70 years (which is the mean female life expectancy), approximately 40-50% of women will have developed osteoporosis and will have sustained at least one fracture. By age 70 years, one woman in eight will have sustained a hip fracture. Does osteoporosis affect only women? As indicated previously, there is an age-related loss of bone in both sexes. However, throughout life women have a lower bone density than men and experience an accelerated rate of bone loss following menopause. By age 65 years, a woman may have lost 50% of her bone mass, while a man will have only lost 25% of bone mass by age 75 years. Because of postmenopausal osteoporosis, the fracture rate in postmenopausal women is greater than that in age-matched men. The female to male ratio for fracture at the femoral neck is 2 to 1 and for crush fracture vertebra is 10 to 1. What is the association between osteoporosis and the menopause? The rate of bone loss accelerates after the menopause because of the increase in bone resorption. While the relative loss of trabecular bone exceeds that of cortical bone , menopause has an adverse affect upon both spinal (predominantly trabecular) and hip (predominantly cortical) bone density. The rate of loss of spinal trabecular bone during the first 5 years after natural menopause may be as much as 5% per annum; after oophorectomy it may be 7-9% per annum. Trabecular bone is metabolically more active and is lost faster than cortical bone possibly because of its greater surface area. The rate of loss of bone begins to decrease approximately 8-10 years after menopause for reasons that are not fully understood. It has been reported that a woman will lose 50% of her trabecular bone density and 35% of her cortical bone density during her lifetime. When the bone density falls below a critical threshold, the risk of fracture correspondingly increases. | 1 | 2 | 3 | 4 | 5 | MAIN PAGE