Sex-and Site-specific Normative Data Curves Of Bone Strength Parameters In Chinese Mainland Population Based On High-resolution Peripheral Computed Tomographic

Objective:1.The primary aim of this study was to use high resolution peripheral quantitative computed tomography to perform finite element analysis on the three-dimensional reconstructed bone to calculate bone strength and establish site-and sex-specific reference centile curves for bone strength parameters in Chinese mainland adults.3.We identified from the centile curves the peak or worst for each bone strength parameters and their age(age_peak)and SD(SD_peak).The populations with the peak value were then used as the reference population to calculate the T-score.Methods:This study used an age-stratified design to recruit 20 to 79 years old Chinese man and women in the form of advertising and education.All subjects underwent HR-pQCT scans after fully understanding the purpose of the study and signed informed consent.Bone strength parameters were obtained after the finite element analysis of scanned bone microstructure parameters.Bone Stiffness（S）、Bone Failure Load（F.ult）、Ratio of force applied on Trabecular bone,at the most distal slice（（Tb.F/TF）dist）、Ratio of force applied on Trabecular bone,at the most proximal slice（（Tb.F/TF）prox）、Apparent Young Modulus measured for the whole bone structure（E.app）、Average Von Mises stresses applied to trabecular bone（Tb.VM）、Average Von Mises stresses applied to cortical bone（C.VM）、Trabecular bone Estimated strain（TB.ES）、Cortical bone Estimated strain（C.ES）were estimated.We used the GAMLSS analysis method to construct the percentile curve of bone strength parameters（3rd,10th,25th,50th,75th,90th,and 97th）,describing the trends in bone strength parameters and the differences in gender distribution.Results:1.The final cohort included 628 participants（253 men and 375 women）.There were627 radii and 607 tibias.2.There were significant changes of distributions for bone strength parameters across the age range.Among them,18 models showed BCCG distribution,11 showed BCPE distribution,1 showed BCT distribution,and the remaining 6 models showed a normal distribution that did not require modeling of skewness or kurtosis.3.At the radius,the peak ages of male bone strength parameters S and F.ult were 20years old,with peak values of 93761.6 N/mm and 5092.7 N,respectively;women reached peak ages of 34 and 33,respectively,with peaks of 63156.1 N/mm and 3481.6N.At the tibia,the peak ages of both men and women are 20 years old,with peaks of274347.2 N/mm,14566.1N and 180320.5 N/mm,9883.7N.The age-related change rate of bone strength parameters（female vs.male）was-0.91%vs.-0.58%in the radius parameter S and-0.95%vs.-0.61%in the parameter F.ult.At the tibia,the parameter S was-0.68%vs.-0.57%and-0.67%vs.-0.54%in the parameter F.ult.4.Bone strength parameters S and F.ult showed different trends with age at the radius and the tibia.Both males and females have relatively stable bone strength before 40 years old and rapid loss after 40 years old.The decline trends of the whole-bone strength parameters S and F.ult at the radius and tibia were different.At the radius,these figures suggest clear declines after around age 50 years,but these trends were not observable at the tibia,while showed a slow and continuous decline at the tibia.Conclusion:1.This is the first study to produce age-,sex-and site-specific centile curves for bone strength parameters by using HR-pQCT.2.Young women had inferior bone strength compared to men,and with age women further disadvantaged by greater decrements.3.The advantages of bone strength in reflecting on bone microstructure and bone density make it possible to improve osteoporosis diagnosis and assessment of fracture risk.