Dual Energy X-Ray Absorptiometry-Based Assessment of Male Patients Using Standardized Bone Density Values and a National Reference Database

Abstract 

Dual energy X-ray absorptiometry (DXA) measurements from different manufacturers provide different bone mineral density (BMD) values and derived T-scores and Z-scores. These differences result partly from technical differences in the algorithms for the determination of bone mineral content and bone area and partly from the use of different manufacturer-derived reference databases. The present study was to implement a uniform expression of BMD in all male patients by using standardized BMD (sBMD) values and referring to a newly established national male reference sample. In 8 bone densitometry centers throughout Belgium 229 young healthy men were measured on Hologic (Bedford, MA) or GE-Lunar (Madison, WI) bone densitometers. Quality control procedures were implemented and site cross-calibration performed using the European Spine Phantom. Absolute BMD values were converted to standardized values by validated formulas (sBMD). Clinically acceptable between-center differences were noted. No discrepancy was observed in terms of mean sBMD and standard deviations at the lumbar spine and proximal femur between the Belgian and the US reference populations. Region-specific sBMD thresholds for the diagnosis of male osteoporosis were calculated. The current data provide a basis to implement a nation-wide, uniform expression of BMD in male patients and allow harmonization of the BMD-based diagnosis and treatment of osteoporosis in men.

Key Words: Cross-calibration, dual energy X-ray absorptiometry (DXA), male osteoporosis, reference ranges, standardized bone mineral density