Age-and Sex-related Differences Of Bone Microarchitecture In Chinese Population: A Cross-sectional High-resolution Peripheral Computed Tomographic Study

Objective:High-resolution peripheral quantitative computed tomography(HR-p QCT)is an advanced 3D imaging modality able to measure cortical and trabecular bone mineral density(BMD),geometry,and microarchitecture in vivo at the peripheral skeletal sites(distal radius and tibia).Furthermore,micro-finite element(?FE)models can be constructed using the image dataset to estimate bone strength.The aim of this study is to summarize results for each decade from 20-80 years old for both male and female to establish age-and sex-specific population-based normative values for HR-pQCT parameters.And to investigate the effcct of age,sex and menopausal status on bone compartmental density,geometry and microarchitecture.Methods:Images of the nondominant distal radius and tibia from a large cohort of Chinese men and women(n=641)aged 20-80 years were obtained using HR-pQCT(Xtreme CT?,Scanco Medical AG,Bruttisellen,Switzerland)with an istropic image voxel size of 61?m.HR-pQCT parameters: total area(Tt.Ar),trabecular area(Tb.Ar),cortical area(Ct.Ar),total volume bone mineral density(Tt.v BMD),trabecular v BMD(Tb.vBMD),cortical vBMD(Ct.vBMD),trabecular bone volume fraction(Tb.BV/TV),trabecular number(Tb.N),trabecular thickness(Tb.Th),trabecular separation(Tb.Sp),inhomogeneity of network(Tb.1/N.SD),cortical thickness(Ct.Th),cortical porosity(Ct.Po)were obtained.Age-and sex-related normative values were eatablished.Then we analyzed age-related patterns of all parameters and compare them between men and women.The effect of age,sex and menopause status on these parameters were also evaluated.Results:1.In the radius,young men compared to young women had larger total and cortical areas(p<0.001),higher Tb.vBMD(p<0.001)and lower Ct.v BMD(p<0.001),larger Tb.BV/TV(p<0.001),Tb.N(p=0.031),Tb.Th(p<0.001)and Ct.Po(p <0.001),smaller Tb.Sp(p=0.012),while there was no difference in Tt.v BMD and Ct.Th between men and women.The results of distal tibia were similar to radius,while young men had larger Tt.vBMD and Ct.Th.2.In both men and women,indices of trabecular parameters peaked at the age of 20 years.In women,indices of cortical parameters in radius and tibia peaked around age 40 and 30 respectively.In men,indices of cortical parameters in radius and tibia peaked around age 45 and 40 respectively.3.With age women was further disadvantaged compared to men by greater decrements in Tt.vBMD(-47.4%),Tb.N(-30%),Ct.Ar(-32.4%),Ct.vBMD(-14.5%),Ct.Th(-38.2%)and increase in Ct.Po(+357%),Tb.Sp(+61.6%),Tb.1/N.SD(+112%)at the radius and decrements Tt.vBMD(-46.4%),Ct.vBMD(-24.4%),Ct.Th(-35.9%)and increase in Ct.Po(+374%)at the tibia.4.Furthermore,cortical bone loss: Ct.Ar(-0.685mm2/y),Ct.vBMD(-4.552mgHA/ccm/y),Ct.Th(-0.013mm/y)occurred significantly after postmenopause compared to that in premenopause,while not trabecular bone.Conclusions:1.This study established age-and sex-specific population-based normative values for HR-p QCT parameters in Chinese men and women.HR-pQCT parameters was affected by age,sex,site and menopausal status.2.Loss of trabecular bone has already occurred at the age of 20 years,while the loss of cortical bone occurred after midlife.The peak age of cortical bone differed by sex and site.3.Young women had inferior microarchitecture compared to men.And with age women are further disadvantaged by greater decrements in cortical and trabecular architecture in the radius and cortical architecture in the tibia.4.The loss of cortical bone was affected by menopausal status.Significant cortical bone loss occurred after postmenopause.