钙摄入量对青春前期女童骨量增长的影响—两年随机干预实验

目的研究不同钙摄入量对于青春前期女童骨量增长的影响,为该人群钙适宜摄入量的修订提供科学依据。方法以年龄10.0±0.7岁的241名青春前期健康女童为对象,设计普通膳食组、牛奶补充组和钙剂补充组三组,总钙摄入量分别为600、900和1200mg/d,进行2年干预,采用多次称量及3d膳食询问法获得2年间日均膳食钙摄入量,使用双能X线骨密度仪测量干预前后全身、腰椎及近端股骨骨矿物密度和骨矿物含量。结果2年间三组的平均钙摄入量分别为552±61、864±139和1166±207mg/d;日均钙摄入量与全身、多位点骨矿物含量和骨矿物密度显著正相关;当日均钙摄入量达到864mg/d时,全身骨矿物含量增加值显著高于钙摄入量为552mg/d膳食组;当日均钙摄入量达到1166mg/d时,股骨颈骨矿物含量及骨矿物密度和腰椎骨矿物密度的增加值显著高于未达到1166mg/d的干预组。结论9～11.5岁的青春前期女童钙摄入量达到1166mg/d,全身特别是负重部位能获得较高骨矿物含量和骨矿物密度增长,提示青春前期钙适宜摄入量可能为1200mg/d。

EFFECT OF CALCIUM INTAKES ON BONE MASS ACCRETION OF PREPUBERTY GIRLS-A TWO-YEAR RANDONMIZED CONTROLLED TRIAL

Objective To observe the effect of different calcium intakes on bone mass accretion of prepuberty girls. Method The trial was a 2-year randomized trial of calcium supplementation on 241 healthy prepuberty girls aged 10.0±0.7 years randomly to three groups: dietary group, milk supplementation group and calcium supplementation group, in which calcium intakes reached 600, 900 and 1200 mg/d respertively. Dietary calcium intakes were estimated by 3 d investigation. The bone mineral content (BMC) and bone mineral density (BMD) of the total body, lumbar spine and proximal femur were measured by dual energy X-ray absorptiometry (DEXA). Results Average calcium intakes of three groups were 552±161, 864±139 and 1166±207 mg/d in two years respectively. There were significantly positive correlation between daily average calcium intakes and BMC or BMD of total body. When calcium intakes reached 864mg/d, the accrual of total body BMC was higher than that below 864mg/d. When calcium intakes reached 1166mg/d, the accrual of femoral neck BMC and BMD and lumber spine BMD were higher than that below 1166mg/d. Conclusion The adequate calcium intakes of prepuberty girls should be 1200 mg/d.