Association of estrogen receptor-alpha gene XbaI polymorphisms and the effect of calcium supplementation on skeletal development in Chinese pubertal girls.

Objective To investigate the association of estrogen receptor-αXbaI polymorphisms concerned with the effect of calcium supplementation on bone mineral density(BMD) and bone turnover markers of Chinese pubertal girls.Method Eighty-eight pubertal girls aged 13-15 years were selected and divided into 2 groups: control and supplemented group.Each group included two subgroups according to the ER-αXbaI polymorphism.BMD,bone turnover markers(BGP,BAP,TRACP),25-OH-VitD3,E2 were measured at baseline and 12 months after calicum supplementation.Results Seventy-two girls completed 12-month study period.The absolute increase of BGP and BMD in distal 1/10 forearm of supplemented group was significantly higher than that in the control group.In the supplemented group,the increase of BAP in Xx genotype was higher than xx genotype and all detected sites BMD in Xx genotype were higher than xx,but were not statistically different.No difference was found in all above index between the two XbaI geontypes in the control group.Conclusion Xx genotype showed better response to calcium supple-mentation than xx,and this hereditory factor should be considered in calcium supplementation.