青少年女性骨量随年龄和人体测量学指标累积的种族差异

Differences in bone density of acquisition with age and anthropometric indices in two races healthy adolescents females

目的了解中国长沙和墨西哥两个种族的青少年女性骨量随年龄和人体测量学指标累积的差异。方法采用双能X线吸收法(DXA)骨密度仪测量718例,年龄9～24岁的中国长沙健康青少年女性腰椎和股骨近端骨密度(BMD)。结果在15岁之前,中国长沙青少年女性的BMD累积率显著低于墨西哥女性。中国长沙青少年女性腰椎和股骨近端BMD比墨西哥女性分别低4.1%和7.8%(均P=0.000)。在体重<44kg和身高<150cm时,中国长沙青少年女性的腰椎BMD显著高于墨西哥女性,但股骨近端BMD始终显著低于墨西哥女性。经身高调整后(BMD/身高),中国长沙青少年女性的腰椎和股骨近端BMD仍然显著低于墨西哥女性。经体重或体重指数(BMI)调整后(BMD/体重或BMI),中国长沙青少年女性的腰椎BMD显著高于墨西哥女性,两者之间股骨近端BMD的差异消失。结论两种族青少年女性的BMD存在种族差异,这种差异主要来自于体重或BMI,而非身高。中国长沙青少年女性如果适当增加体重,这种差异有可能消失。

Objective In this study we examined racial differences in BMD acquisition with age and anthropometric indices in healthy adolescent Chinese and Mexican females, Methods We measured the BMD of the posteroanterior （PA） lumbar spine, and proximal femur using dual-energy X-ray absorptiometry （DXA） in a total of 718 healthy adolescent Chinese females, aged 9 - 24 years. Results Before age 15, the cumulative rates of BMD acquisition in Chinese adolescents weresignificantly lower than those of Mexican individuals. The BMDs of Chinese adolescents in the PA spine and femur were 4, 1% and 7.8% lower than those of Mexican adolescents, respectively （ P = 0.000）. The spine BMDs of Chinese adolescents was markedly higher than that of Mexican adolescents when weight was less than 44 kg and height was less than 150 cm, while the femoral BMD was always lower. After BMD values were adjusted for height （ BMD/height）, the spine and femoral BMDs of Chinese females were still significantly lower than those of Mexican females. After BMD values were adjusted for weight or BMI （BMD/weight or BMI）, the PA spine BMDs of Chinese females were significantly higher than that of Mexican females, and the difference in femur BMD between two groups was no longer significant. Conclusion These results indicate racial differences in BMD between healthy Chinese and Mexican female adolescents. These differences are mainly due to weight and BMI, rather than height.