Background/Purpose:  Bone mineral density(BMD) by dual X-ray absorptiometry(DXA) is currently standard clinical tool for predicting osteoporotic fracture. However, DXA doesn’t allow studying abnormalities that predict different fracture risks independent of areal BMD, such as trabecular and cortical bone compartments and bone microarchitecture. High-resolution peripheral quantitative computed tomography(HR-pQCT) is non-invasive method to assess cortical and trabecular microarchitecture and bone mechanical competence in clinical studies on postmenopausal women with low bone mass. However, there are no studies on HR-pQCT in general elderly population. Thus, we sought to verify the association between fragility fractures and bone microarchitecture and strength using HR-pQCT and markers of bone turnover in older adults.

Methods:  276 older adults were assessed by questionnaire. Lateral scans of spine obtained from Vertebral Fracture Assessment (VFA) by DXA were done to assess vertebral fractures (semiquantitative method). HR-pQCT was performed at the distal radius and tibia and following parameters were analyzed: volumetric bone mineral density(vBMD) – total(Tt), trabecular(Tb) and cortical(Ct), structural parameters – trabecular number(Tb.N), trabecular thickness(Tb.Th.), trabecular separation(Tb.Sp), cortical thickness(Ct.Th) and strength variables – Stiffness(S), Estimated ultimate failure load(Fult) and Apparent modulus(Epp). Serum levels of aminoterminal propeptide of procollagen type I(PINP) and C-terminal telopeptide of type I collagen (CTX) were evaluated.

Results:  The mean age was 79.4± 4.1 years. According to DXA, osteopenia and osteoporosis were observed in 44.2% and 38.9%, respectively. At least one vertebral fracture was observed in 56.2% of subjects. At distal tibia, individuals with vertebral fractures had lower vBMD(Tt.vBMD, p=0.001; Tb.vBMD, p<0.001), lower Tb.N, p<0.001, higher Tb.Sp, p<0.001 and lower strength parameters(S, p=0.002; F.ult, p=0.002; E.app, p=0.034). At distal radius, subjects with vertebral fractures had lower volumetric density(Tt.BMD,p<0.001; Tb.BMD,p<0.001; Ct.BMD,p=0.021), lower structural parameters(Tb.N,p<0.001; Tb.Th, p=0.030; Ct.Th,p=0.013), higher Tb.Sp,p<0.001; and lower bone strength(S, F.ult, E.app). Bone turnover markers were significantly different between fracture and non fracture groups: CTX (0.25 ± 0.16 vs. 0.30 ± 0.18 ng/mL, p=0.004) and P1NP(38.2 ± 29.2 vs. 40.6 ± 19.5 ng/mL, p=0.035). After adjusting for potential confounding variables, logistic regression model revealed that Tb.vBMD at distal tibia (OR 0.98, 95%CI 0.98–0.99, p<0.001)) and CTX (OR 0.821, 95%CI 0.697–0.966, p=0.017) were independently associated with vertebral fractures

Conclusion:  HR-pQCT detected marked differences on bone microstructure between older adults with vertebral fractures and those without fractures independent of areal BMD by DXA. Lower trabecular volumetric BMD was independently associated with vertebral fracture in community-dwelling elderly. Moreover, lower CTX was also linked to vertebral fracture and could indicate low bone turnover as risk factor for fractures in advanced-aged population.

« Back to 2016 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/assessment-of-high-resolution-peripheral-quantitative-computed-tomography-parameters-and-markers-of-bone-metabolism-in-community-dwelling-elderly-with-and-without-vertebral-fractures-the-sao-paulo-a/