Objective To investigate the association of estrogen receptor alpha(ER-α) PvuII polymorphisms with the effect of calcium supplementation on bone development in Chinese pubertal girls,and to study the importance of calcium supplementation by maximizing the peak bone mass at their pubertal stage for bone development and osteoporosis prevention and the role of estrogen in regulating bone mass.Methods Ninety-four pubertal girls were recruited in the study and divided into two groups and three sub-groups according to the ER-α PvuII polymorphisms.One year before and after calcium supplementation,bone mineral density(BMD) was measured by DEXA,while BGP,BAP,TRACP5b,and 25-OH-VitD3,as well as estrogen were detected by ELISA.Analysis of covariance was used to examine the effect of ER-α polymorphisms on bone development.Results The absolute increase and percentage change of BGP were significantly higher in the supplemented group than in the control group(P<0.05) .In the intervened group,The increase and percentage change of the total body and radio distal 1/3 BMD were higher in PP than in PP genotype(P<0.05) ,and the increase of BAP in Pp was also higher than PP in the same group(P<0.05) .Conclusion PP genotype shows a better response to calcium supplementation than the other PvuII polymorphisms. Objective To investigate the association of estrogen receptor alpha (ER-α) PvuII polymorphisms with the effect of calcium supplementation on bone development in Chinese pubertal girls, and to study the importance of calcium supplementation by maximizing the peak bone mass at their pubertal stage for bone development and osteoporosis prevention and the role of estrogen in regulating bone mass. Methods Ninety-four pubertal girls were recruited in the study and divided into two groups and three sub-groups according to the ER-α PvuII polymorphisms. One year before and after calcium supplementation, bone mineral density (BMD) was measured by DEXA, while BGP, BAP, TRACP5b, and 25-OH-VitD3, as well as estrogen were detected by ELISA. Analysis of covariance was used to examine the effect of ER-α polymorphisms on bone development. Results The absolute increase and percentage change of BGP were significantly higher in the supplemented group than in the control group (P <0.05) .In the intervened group, The in crease and percentage change of the total body and radio distal 1/3 BMD were higher in PP than in PP genotype (P <0.05), and the increase of BAP in Pp was also higher than PP in the same group (P <0.05) .Conclusion PP genotype shows a better response to calcium supplementation than the other PvuII polymorphisms.