Phenotype measurement
Dual-energy X-ray absorptiometry (Prodigy Advance; General Electric Company, Fairfield, CT, USA) measurements at the lumbar spine and femur were obtained from all patients, following standard protocols. We distinguished and analyzed three BMD phenotypes—lumbar spine (L1-L4) (LS-BMD), femur neck (FN-BMD), and femur total (FT-BMD)—identified here as the average value of mineral density at the neck and greater trochanter of the femur bone.