Background: Bone mineral density (BMD) is a key predictor of fracture risk in postmenopausal women. Evidence on the influence of fat and lean mass (LM) on BMD remains contradictory. This study aimed to assess the associations between BMD at different sites (whole-body, upper, and lower limbs) and anthropometric and body composition variables measured by dual energy X-ray absorptiometry (DXA) in postmenopausal women. Methods: A cross-sectional study was conducted on 308 healthy postmenopausal women. Anthropometric data and whole-body DXA scans were used to measure BMD, total fat mass (FM), LM, appendicular LM index (ALMI), and abdominal fat. Pearson or Spearman correlation analyses were used according to variable distribution, and a correlation matrix along with variance inflation factor analyses was used to reduce 18 variables to a final set of 5. Multiple linear regression models were built for BMD at each site. Results: Age was negatively correlated with BMD at all sites. Total LM and ALMI demonstrated positive correlations with BMD, whereas body mass index (BMI) and abdominal fat exhibited weaker positive associations. In multivariable analyses, age was negatively associated with whole-body BMD, while total LM was positively associated. For lower-limb BMD, age and total LM were significant predictors, with BMI showing a positive but weaker association. For upper-limb BMD, total LM, and ALMI were all positively associated. The models demonstrated satisfactory fit (adjusted R², 0.341-0.438; global P<0.0001). Conclusions Age and total LM were independently and consistently associated with BMD in postmenopausal women, whereas FM and BMI had a limited impact.

Background: There are age- and sex-related increases in the prevalence of osteoporosis. Bone densitometry based on dual energy X-ray absorptiometry (DXA) is the gold standard for the assessment of bone mineral density (BMD). Three-dimensional (3D) analysis of the proximal femur (3D-DXA) allows discrimination between cortical and trabecular compartments, and it has shown a good correlation with computed tomography. We aimed to assess age- and sex-related volumetric density differences in trabecular and cortical bone using 3D-DXA and determine the reference intervals for integral volumetric (v)BMD within the Argentine population. Methods: Healthy female and male adult subjects (N=1,354) from Argentina were included. Hip BMD was measured using DXA, and 3D analysis was performed using 3D-Shaper software. The integral vBMD, cortical surface BMD, and trabecular vBMD (trab vBMD) were measured. Results: The study population included 73.9% women (N=1,001) and 26.13% men (N=353). We found a significant decrease in integral vBMD between 20 and 90 years in both sexes (women, -23.1%; men, -16.6%). Bone loss indicated in the integral vBMD results was mainly due to a decrease in trabecular bone in both sexes (women, -33.4%; men, -27.7%). The age-related loss of cortical bone density was less and was limited to the female population, without no age-related differences in men. Moreover, 3D-DXA allowed us to propose reference intervals for integral vBMD. Conclusions We found age- and sex-related bone loss between 20 and 90 years in an Argentine cohort via integral vBMD measurements using 3D-DXA, mainly due to decreases in trabecular bone in both sexes. The age-related loss of cortical bone density was less and was limited to the female population.

Background: There are age- and sex-related increases in the prevalence of osteoporosis. Bone densitometry based on dual energy X-ray absorptiometry (DXA) is the gold standard for the assessment of bone mineral density (BMD). Three-dimensional (3D) analysis of the proximal femur (3D-DXA) allows discrimination between cortical and trabecular compartments, and it has shown a good correlation with computed tomography. We aimed to assess age- and sex-related volumetric density differences in trabecular and cortical bone using 3D-DXA and determine the reference intervals for integral volumetric (v)BMD within the Argentine population. Methods: Healthy female and male adult subjects (N=1,354) from Argentina were included. Hip BMD was measured using DXA, and 3D analysis was performed using 3D-Shaper software. The integral vBMD, cortical surface BMD, and trabecular vBMD (trab vBMD) were measured. Results: The study population included 73.9% women (N=1,001) and 26.13% men (N=353). We found a significant decrease in integral vBMD between 20 and 90 years in both sexes (women, -23.1%; men, -16.6%). Bone loss indicated in the integral vBMD results was mainly due to a decrease in trabecular bone in both sexes (women, -33.4%; men, -27.7%). The age-related loss of cortical bone density was less and was limited to the female population, without no age-related differences in men. Moreover, 3D-DXA allowed us to propose reference intervals for integral vBMD. Conclusions We found age- and sex-related bone loss between 20 and 90 years in an Argentine cohort via integral vBMD measurements using 3D-DXA, mainly due to decreases in trabecular bone in both sexes. The age-related loss of cortical bone density was less and was limited to the female population.

Background: There are age- and sex-related increases in the prevalence of osteoporosis. Bone densitometry based on dual energy X-ray absorptiometry (DXA) is the gold standard for the assessment of bone mineral density (BMD). Three-dimensional (3D) analysis of the proximal femur (3D-DXA) allows discrimination between cortical and trabecular compartments, and it has shown a good correlation with computed tomography. We aimed to assess age- and sex-related volumetric density differences in trabecular and cortical bone using 3D-DXA and determine the reference intervals for integral volumetric (v)BMD within the Argentine population. Methods: Healthy female and male adult subjects (N=1,354) from Argentina were included. Hip BMD was measured using DXA, and 3D analysis was performed using 3D-Shaper software. The integral vBMD, cortical surface BMD, and trabecular vBMD (trab vBMD) were measured. Results: The study population included 73.9% women (N=1,001) and 26.13% men (N=353). We found a significant decrease in integral vBMD between 20 and 90 years in both sexes (women, -23.1%; men, -16.6%). Bone loss indicated in the integral vBMD results was mainly due to a decrease in trabecular bone in both sexes (women, -33.4%; men, -27.7%). The age-related loss of cortical bone density was less and was limited to the female population, without no age-related differences in men. Moreover, 3D-DXA allowed us to propose reference intervals for integral vBMD. Conclusions We found age- and sex-related bone loss between 20 and 90 years in an Argentine cohort via integral vBMD measurements using 3D-DXA, mainly due to decreases in trabecular bone in both sexes. The age-related loss of cortical bone density was less and was limited to the female population.