Femoral neck and spine bone mineral density-Surrogate marker of aortic calcification in postmenopausal women

OBJECTIVE: Osteoporosis and abdominal aortic calcification (AAC) are associated with increased morbidity and mortality in postmenopausal women. The aim of this study was to determine the accuracy of anterior-posterior (AP) dual-energy X-ray absorptiometry (DXA) compared with that of X-ray lateral lumbar radiography (LLR) in detecting and scoring AAC. METHODS: In this cross-sectional study conducted in 56 postmenopausal asymptomatic females aged 59.0±9.3 years and who never used medications to treat osteoporosis before, we determined femoral neck and lumbar spine bone mineral density (BMD) by AP DXA and AAC by X-ray LLR. We hypothesized that the subtracted femoral neck BMD (BMD(FN)) from lumbar spine BMD (BMD(LS)) presented as ΔBMD=BMD(LS)–BMD(FN) would have a diagnostic value in detecting abdominal vascular calcification. RESULTS: The mean BMD(FN) was 0.744±0.184 g/cm(2), and the mean BMD(LS) was 0.833±0.157 g/cm(2) (p<0.0001); the mean ΔBMD was 0.089±0.077 g/cm(2), and the mean AAC score was 2.182±1.982. Bivariate Pearson’s correlation analysis revealed a significant positive correlation between AAC and ΔBMD (r=0.449, p=0.0006); by linear regression analysis, R(2)=0.2019, and by multiple regression analysis, βst=13.5244 (p<0.0001). We found a sensitivity of 64.3% and specificity of 82.9% by receiver operating characteristic [ROC; area under the ROC curve (AUC=0.759)] in the prediction of AAC by ΔBMD. CONCLUSION: This AP subtracting BMD DXA method provides a useful tool for detecting and scoring subclinical and extensive AAC in postmenopausal women using a simple, semiquantitative, and accurate scoring system with minimal radiation exposure and low cost.