Analysis of the bone mineral density and bone mineral content among primary and middle school students in Yinchuan

Objective To explore the change of bone mineral density and changing tendency of bone mineral content among children and adolescents,and to provide a scientific basis for the promotion of healthy bone development among children and adolescents in Yinchuan.Methods Present situation research and stratified cluster sampling method were used to select 1 614 children and adolescents aged 7-18 years from Yinchuan.All of them were investigated with questionnaire,physical measurement and DXA measurement.Results The average BMD was (0.89±0.12)g/cm2 and the BMC was (1 548.40±477.04)g.With the growing of age,the levels of BMD and BMC of both boys and girls were on the rise.The BMD and BMC between boys and girls demonstrated "twice intersections" during growth period.The first crossover of BMD was found at the age of 11,then the second one was at 15 years old.The first crossover of BMC was found at the age of 10,and the second one was at the age of 14.The BMD and BMC of boys were higher than girls before the first crossover and after the second cross(P<0.05).There was no statistical difference in the level of BMD and BMC between Han ethic group and Hui ethic group (t =-1.876,-1.838,P>0.05).Conclusion The BMD and BMC of children and adolescents in Yinchuan increased with age and were correlated with gender.It is suggested that the BMD and BMC should be measured periodically to prevent the occurrence of osteoporosis among children and adolescents.