Normative Database for HR-pQCT-Based Radius and Tibia Strength

Objective: De novo determination of sex- and age-specific reference intervals for vBMD, bone architecture, and bone strength assessed by 3D HR-pQCT with a resolution of 61 µm (Xtreme CT II, Scanco Medical, Brütisellen, Switzerland) in the Swiss population. Design: Population-based, age- and sex-stratified, cross-sectional study in a single centre. Study Size: For the main part, 480 valid data sets will be needed for two age reference intervals for both women and men. The number of double/triple stack scans will be between 1 and 3 depending on graded motion artefacts. Among the 120 participants of each reference interval, 21 will be needed to assess reproducibility. For these volunteers, the number of double/triple stack scans will be equal to 3. Project Assessments, Procedures: participant demographics and physical activity will be obtained and the validated Swiss FRAX questionnaire will be filled to determine the epidemiology-based 10-year fracture risk. Grip strength will be measured. A DXA measurement at the hip will be done according to the standard protocol of the Universitätspoliklinik für Osteoporose. For participants at elevated vertebral fracture risk, lateral and antero-posterior DXA of the spine will be added for vertebral fracture assessment (VFA) and spine areal bone mineral density (aBMD). The HR-pQCT examination per se consists then of up to 3 repeated double stack scans at the distal radius and triple stack scans at the distal tibia.