Association between demographic characteristics and 3D DXA measurements in the femoral neck of healthy Spanish postmenopausal women.

PURPOSE: Limited data exists on the association between 3D-DXA variables and demographic data (age, years since menopause, and BMI).

AIM: Determine the relationship between 3D structural parameters and body demographics in a healthy, postmenopausal group of women.

METHODS

We used new 3D-DXA software to measure femoral neck (FN) in a cross-sectional study included all postmenopausal women referred for densitometric evaluation at Jiménez Díaz Foundation Hospital over a one-year period, using consecutive sampling. Data of all participants (n = 245) was obtained from hospital records. Participants were selected using exclusion criteria such as the presence of osteoporosis by DXA (T-score <-2.5), hormonal disorders, cancer, or a history of therapies that influence bone metabolism. BMI was calculated using updated weight and height measurements. DXA scans were performed using a HOLOGIC QDR-4500 device, and 3D-DXA analysis of the femur were obtained using 3D-SHAPER software. Relationships were assessed using Pearson's correlation coefficient and linear regressions. The explanatory variables were age, BMI, and years since menopause. Multivariable linear regression models were applied to adjust for main confounding factors.

RESULTS

FN aBMD correlated positively with cortical sBMD (r = 0.73, p < 0.001), Trabecular vBMD (r = 0.71, p < 0.001), Integral vBMD (r = 0.71, p < 0.001), Cortical vBMD, r = 0.52, p < 0.001) and Cth (r = 0.71, p < 0.001). Significant positive correlation between the following 3D data were found with BMI: FN aBMD (r = 0.28, p < 0.001); cortical sBMD (r = 0.39, P < 0.001; Trabecular vBMD (r = 0.26,p < 0.001); integral vBMD (r = 0.34,p < 0.001); Cortical vBMD (r = 0.41, p < 0.001) and Cth (r = 0.24, p < 0.001). We do not find correlation between age and years from menopause with these parameters, except trabecular vBMD and age (r = 0.27, p < 0.001) and integral vBMD and age (r = 0.22, p < 0.001).

CONCLUSIONS

The use of 3D DXA software confirms a significant correlation between the structural parameters of the femoral neck and BMI, but not between the age of the women and the time of their menopause.