Femoral bone mineral density reference values by sex and ethnicity: Findings from the Qatar Biobank study

Low bone mineral density (BMD) is a major global health concern due to fracture-related morbidity and mortality. BMD is currently assessed by dual-energy X-ray absorptiometry (DXA) against a US reference population. The aim of the study was to establish an ethnicity- and sex-specific reference for calculating BMD at different femoral sites including femoral trochanter, Ward's triangle and femoral neck in Qatar.

This cross-sectional study analyzed BMD in 4727 (2277 females and 2450 males) healthy Qatari aged between 20 and 82 years participating in the Qatar Biobank (QBB) study. Standard T-scores provided by the densitometer (T_DXA) were compared with ethnicity- and sex-specific T-scores for the Qatari population (T_QA) calculated using data from the 20-29-year age group for different femoral sites as the reference. The concordance between T_DXA and T_QA was analyzed using kappa statistics.

Males consistently exhibited higher BMD values for the femoral trochanter, Ward's triangle, and the femoral neck across all age groups compared with females. Using T_QA rather than T_DXA as a reference at any site classified fewer individuals as having osteoporosis and osteopenia, especially for females. Agreement between T_DXA and T_QA was higher in males than in females.

These findings underscore the need for local ethnicity- and sex-specific BMD reference values. The use of T_QA significantly reduced overdiagnosis of osteopenia and osteoporosis compared with T_DXA, thereby decreasing overtreatment and impacting participant recruitment decisions into clinical studies.