补钙16个月对青春期男女生骨量的影响

目的探讨不同钙摄入量对我国青少年骨量的影响。方法对北京郊区337人(平均年龄为13.6岁)开展为期16个月的双盲对照干预研究,每天给予3次不同剂量碳酸钙片,每片含60IU维生素D,用双能X线吸收仪(DXA)测定全身、腰椎和前臂骨量。结果女生全身骨矿物密度的年增长率由低钙摄入组到高钙摄入组逐渐升高,调整混杂因素后差异消失。女生前臂远端1/3处和男生前臂远端1/10处的骨矿物含量年增长率和骨面积年增长率均以每天钙摄入900～1100mg/d的人群(平均钙摄入量984mg/d)最高,其中调整混杂因素后男生差异消失。结论青春期钙摄入量达到1000mg/d以上可促进青少年骨量增长,此结果有性别差异。

The Effect of 16-month Calcium Supplementation on Bone Mass Accrual of Adolescents

Objective To observe the effect of calcium supplementation on bone mass accrual in Chinese adolescents. Methods A sixteen-month double-blind randomized intervention trial. Total 337 healthy adolescents aged 11.4-16.1 years were supplied with calcium tablets with 60 IU vitamin D three times per day in four dose groups. The bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) of the total body, spine and non-dominant forearm were measured by dual energy X-ray absorptiometry (DEXA). Results The annual increase percentage of total body BMD in Group 4 for girls was significantly higher than that in other groups. In Group 3, the annual increase percentages of BMC and BA in proximal forearm of girls and in distal forearm of boys were significantly higher than that in Group 2 and Group1. However, all difference between groups disappeared after adjustment for potential confounders except proximal forearm BMC and BA annual accrual in girls. Conclusion When calcium intake was more than 1 000 mg/d, the bone mass annual increase percentage of adolescent were higher than those of lower calcium intake. The effect of calcium supplementation was different in adolescent boys and girls.