Age-,Site-and Gender-Specific Reference Centile Curves And Normative Data For HRpQCT-derived Bone Structural Parameters In Chinese Mainland Population

Objective:This study aims to provide age-,site-and gender-specific population-based centile curves and normative data of HRpQCT parameters for reference population dwelling in Chinese mainland.Based on the curves,the change patterns of these bone parameters across different age periods would be investigated.We would also like to explore the additional or combined value of HRpQCT parameters with other traditional fracture assessment tools in evaluating vertebral fracture risk in postmenopausal women.Methods:With cross-sectional design,images of nondominant(and non-fracture)distal radius and tibia were obtained using HRpQCT(Xtreme CTⅡ)from 863 healthy participants(253 men,610 women)aged 20 to 80 years dwelling in Beijing.After images of lower quality were excluded,bone structural parameters including volume bone mineral density,bone geometry and bone microarchitecture were evaluated with standard software.Age-site-and gender-specific centile curves were established using generalized additive models for location,scale,and shape(GAMLSS)with age as the only explanatory variable.Peaking age,peak value and change patterns of all HRpQCT parameters were investigated according to different age periods.Then we analyzed data from 207 postmenopausal women in ChiVos study with logistic regression and areas under receiver operating characteristics(ROC)curves.We compared how well HRpQCT parameters,FRAX(for major or hip osteoporotic fractures,with and without femoral neck BMD adjusted),and height change alone or in combination to discriminate between those with or without radiographic vertebral fracture.The analyses were repeated in subgroups with osteopenia/normal BMD defined by Dual Energy X-ray Absorptiometry(DXA)and low fracture risk defined by Fraxture assessment tool(FRAX).Results:1.In women,cortical bone structure peaked during forth decade no matter it was measured at radius or tibia.However,in men cortical bone peaked before 20 at tibia but much later at radius(fifth decade).Most trabecular parameters have reached their peak values at 20 years old regardless of gender and site2.Trabecular bone loss started from early young adulthood in both genders.Cortical bone loss was significantly accelerated after 50 while trabeculae deteriorated at a steady speed or even decelerated.Compared to men,women suffered more of their bone loss after 50,particularly trabecular ones.Compared to tibia,more radial structure loss was completed after 50 years old.It was Ct.Po that changed most dramatically with ageing.3.For clinical application,we reported gender-,site-and age-specific reference data by centiles(1st,3rd,15th,25th,75th,85th,95th,97th,and 99th)and Z-scores(-3.0,-2.5,-2.0,-1.5,-1.0,0,1.0,1.5,2.0,2.5,3.0)for Chinese mainland population for HRpQCT bone parameters at distal radius and tibia.4.Generally,incorporating HRpQCT indices,especially trabecular parameters into traditional fracture assessment tool(aBMD and FRAX)had additional value in discriminating postmenopausal women with radiographic vertebral fracture from those healthy ones.Results were similar in subgroup analyses.Conclusions:The study established age-,site-and gender-specific centile curves of HRpQCT parameters for Chinese mainland population.The strict criteria to include "healthy participants" only guaranteed its validity in assessing the gap between someone’s bone microstructure and a desirable target.HRpQCT parameters might be useful in improving predictive ability of osteoporotic fracture risk but need more large-size longitudinal studies to confirm.The study would be meaningful in facilitating the understanding of bone microarchitecture of different ethnicities.It also provides basis for evaluating bone microstructural damage under a variety diseases for people with same genetic background.