Tibial or hip BMD predict clinical fracture risk equally well: results from a prospective study in 700 elderly Swiss women

Abstract

Summary In a randomly selected cohort of Swiss communitydwelling elderly women prospectively followed up for 2.8± 0.6 years, clinical fractures were assessed twice yearly. Bone mineral density (BMD) measured at tibial diaphysis (T-DIA) and tibial epiphysis (T-EPI) using dual-energy X-ray absorptiometry (DXA) was shown to be a valid alternative to lumbar spine or hip BMD in predicting fractures. Introduction A study was carried out to determine whether BMD measurement at the distal tibia sites of T-EPI and T-DIA is predictive of clinical fracture risk. Methods In a predefined representative cohort of Swiss community-dwelling elderly women aged 70-80 years included in the prospective, multi-centre Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture risk (SEMOF) study, fracture risk profile was assessed and BMD measured at the lumbar spine (LS), hip (HIP) and tibia (T-DIA and T-EPI) using DXA. Thereafter, clinical fractures were reported in a bi-yearly questionnaire. Results During 1,786 women-years of follow-up, 68 clinical fragility fractures occurred in 61 women. Older age and previous fracture were identified as risk factors for the present fractures. A decrease of 1 standard deviation in BMD values yielded a 1.5-fold (HIP) to 1.8-fold (T-EPI) significant increase in clinical fragility fracture hazard ratio (adjusted for age and previous fracture). All measured sites had comparable performance for fracture prediction (area under the curve range from 0.63 [LS] to 0.68 [T-EPI]).Conclusion Fracture risk prediction with BMD measurements at T-DIA and T-EPI is a valid alternative to BMD measurements at LS or HIP for patients in whom these sites cannot be accessed for clinical, technical or practical reasons.

Microstructural Parameters of Bone Evaluated Using HR-pQCT Correlate with the DXA-Derived Cortical Index and the Trabecular Bone Score in a Cohort of Randomly Selected Premenopausal Women

“…Whereas the tibial epiphysis (T-EPI) consists predominantly of trabecular bone, the tibial diaphysis (T-DIA) is predominantly composed of cortical bone. The authors previously showed that, in a cohort of randomly selected postmenopausal women, aBMD measured by DXA at both tibial subregions was predictive for non-vertebral fracture risk [17]. T-scores were generally higher at the T-DIA than at the T-EPI suggesting that the T-DIA might be suitable for identifying other contributors of an individual’s fracture risk, including parameters related to the shape and size.…”

Cortical parameters predict bone strength at the tibial diaphysis, but are underestimated by HR‐pQCT and μCT compared to histomorphometry

“…The T ‐scores were calculated as the number of standard deviations from the mean peak bone mass of a female reference population of 400 healthy Caucasians living in the area of Bern, Switzerland. Peak bone mass (mean value ± SD ) of this female reference population is 1.278 ± 0.116 g/cm 2 at the distal tibial diaphysis (Popp et al, 2009).…”

“…The manufacturer's software was used according to a previously described standardized procedure for analysing the tibial diaphysis (Casez et al, 1994). Briefly, the region of interest (ROI) for the tibial diaphysis started 130 mm from the distal tibia endplate and included a total length of 40 mm of the long bone axis running from proximal to distal (Figure 1a; Popp et al, 2009). The T ‐scores were calculated as the number of standard deviations from the mean peak bone mass of a female reference population of 400 healthy Caucasians living in the area of Bern, Switzerland.…”

Distinct phenotype of kidney stone formers with renal phosphate leak

“…If TRP was > 86%, then the formula: TmP/GFR (mmol/l) = (0. Hologic, Bedford, MA, USA) at the lumbar spine, the non-dominant femoral neck, the proximal femur and the distal tibia diaphysis and epiphysis as described [21,22].…”