北京城区10?12岁女孩骨密度的研究

目的 观察10－12岁女孩骨密度（BMD）的变化。方法 对375例健康女孩行全身扫描和左前臂扫描，按首位（10岁）平均体重指数（BMI）分组为超重组（BMMI＞19．6）、正常组（BMI＝14．2－19．6）、偏轻组（BMI＜14．2）。1年和2年后，利用同台双能X线骨密度仪再次扫描，连续3年追踪观察该年龄段女孩每年BMD的变化。结果 全身各部位的BMD值和全身总的骨矿含量（BMC）值第2年明显高于第1年（P＜0．01－0．001）。第3年（12岁）与第2年（11岁）相比：仅前臂远端1／10处BMD值有明显增加（P＜0．001），前臂远端1／3处BMD值和全身总的BMD值无增加，且全身总的BMD值略有下降（P＞0．05）；但全身总的BMC值有明显增加（P＜0．001）。BMD、BMC值均以超重组最高，正常组次之，偏轻组最低。结论 青春期女孩不同部位的BMD值年增长率快慢不一，但全身总的BMC值总是随着年龄增长而增加。

Bone mineral density measurement in 10-12 year-old girls in Beijing

Objective\ To observe the change of bone mineral density (BMD) in Beijing girls aged 10 12 years. Methods\ 375 healthy girls undergoing whole body and left forearm scanning for BMD were divided into three groups according to the body mass index of the first measurement; overweight group (BMI>19.6),normal group (BMI=14.2-19.6) and underweight group (BMI<14.2).The second and the third measurement were done by the same dual energy X\|ray densitometer after one and two years. Results\ The value of second measurements were higher than those of first measurements in BMD of the different sites and in bone mineral content (BMC) of total body ( P <0.01-0.001). Compared with the second measurement (11 years), the third (12 years) measurement results showed that BMD of distal 1/10 left forearm increased significantly with age ( P<0.001) ,BMD in 1/3 of left forearm and BMD of total body were not significantly different,but BMD of total body declined slightly ( P>0.05 ).However,BMC of total body in third measurement was higher than that in the second measurement ( P< 0.001).BMD and BMC were highest in the overweight group,the second in the normal group, and lowest in the underweight group. Conclusion\ BMD of different sites are different in annual growths rate in pubertal girls,but BMC of total body always increase with their age.