ROLE OF SEX STEROIDS IN AGE-RELATED BONE LOSS

据信，峰值骨量是骨代谢中的关键因素。 确定骨质疏松性骨折风险。在骨峰值的时候 骨量存在1 SD的黑白差异， 大大减少了50%的老年黑人中的骨质疏松性骨折， 这种峰值骨量的差异必须反映出 黑人和白色儿童骨骼生长过程的不同， 本研究建议的A部分的目的是调查： l）儿童骨量增加率的黑白差异 年龄5-14岁; 2）骨骼转换标志物与 黑人和白色儿童的骨量增加率， 差异解释骨骼生长的差异; 3）因素 这可能会通过影响骨骼， 在生长过程中建模和重塑，或通过其他机制， 包括性类固醇、生长激素和其他生长因子。部分 B我们还建议研究骨骼重建在骨量中的作用 以及黑人和白色成年人之间骨质流失的差异。我们将研究 老年人骨量和骨量变化率的差异 黑人和白色男性和女性，并调查是否变化率， 骨骼重塑与骨骼质量的变化率有关。 我们还将测试性类固醇是否存在差异， 与骨量、骨质流失、骨标记物的差异相关 重塑，或对骨骼质量的其他潜在影响（例如， 肌肉质量）。

It is believed that peak bone mass is a critical element in the determination of risk for osteoporotic fractures. At the time of peak bone there is a 1 SD black-white difference in bone mass which must contribute greatly to the 50% reduction in osteoporotic fractures among elderly black men and women in the U.S. This difference in peak bone mass must reflect processes which differ in black and white children during skeletal growth, and it is the purpose of Part A of this proposed research to investigate: l) the black-white differences in rates of gain in bone mass in children aged 5-14; 2) the relationship between markers of skeletal turnover and rates of gain in bone mass in black and white children, and whether such differences account for differences in skeletal growth; and 3) factors which might influence bone mass either through effects on skeletal modeling and remodeling during growth, or through other mechanisms, including sex steroids, growth hormone and other growth factors. In Part B we propose to also study the role of skeletal remodeling in bone mass and bone loss differences among black and white adults. We will examine both differences in bone mass and rates of change in bone mass in older black and white men and women, and investigate whether changes in rates of skeletal remodeling are associated with rates of change in skeletal mass. We will also test whether there are differences in sex steroids which are associated with differences in bone mass, bone loss, markers of remodeling, or other potential influences on the skeletal mass (e.g. muscle mass).