Forearm bone mineral density measurement with different scanning positions: a study in right-handed Chinese using dual-energy X-ray absorptiometry.

The purpose of our study was to determine whether different scanning positions influence forearm bone mineral density (BMD) measurements and to evaluate the association between forearm BMDs in different scanning positions and those of other skeleton sites. The study population consisted of 30 right-handed healthy Chinese volunteers. BMD was measured with GE Lunar Prodigy at the left forearm in both sitting and supine positions, and at lumbar spine and the right femur. All subjects received repeated measurements in the same day (repositioning), and the average of repeated BMD results was used for analysis. The BMD precision errors of the nondominant forearm in the sitting and supine positions varied from 1.13% to 2.46%. There were no statistically significant differences between BMD precision errors for each region of interest (ROI) between sitting and supine positions (all the p values were greater than 0.05). When comparing BMDs on the same side in the sitting position with those in the supine position, there were significant differences at both the 1/3 radius level and in the total radius (p<0.05). The BMD values at these ROIs obtained in the supine position were lower than those in the routine sitting position. The BMDs of the ultradistal radius in the both 2 different scanning positions were significantly associated with lumbar spine and femoral neck BMD, respectively. The total radius BMD in the different positions was associated with the BMD of the femoral neck. A change in body scanning position from sitting to supine will significantly influence forearm BMD results.

[Change in body compositions in female patients with human immunodeficiency virus related lipodystrophy syndrome].

OBJECTIVE: To study the changes of body composition in females patients with human immunodeficiency virus (HIV)-related lipodystrophy (LD) syndrome (HIV-LD). METHODS: Totally 25 female patients who were treated in our hospital from January 2002 to December 2009 were divided into LD group and non-LD group based on the existence of LD. All these patients were receiving highly active antiretroviral therapy (HAART). In addition, 12 healthy women were set as the controls. Total and regional body composition were measured by dual X-ray absorptiometry in all three groups. RESULTS: The fat mass (FM) was correlated negatively with the duration of HAART (r=-0.431, P=0.029). Multiple linear regression analysis showed that FM had positive correlation with weight and negative correlation with lean mass (LM) (r = - 0. 973, P =0. 000). Total, trunk and leg FM were significantly lower in LD patients than that in controls (P <0.05).Meanwhile, total, trunk and leg bone mineral contents were statistically lower in LD patients than that in controls (P <0. 05). Lumbar bone mineral density of LD patients was lower than that of non-LD patients and controls, and there was significant difference between LD patients and controls (P = 0. 001). LM of LD patients was higher than that of non-LD patients but without statistical difference (P > 0. 05). CONCLUSIONS: The peripheral and central FM and bone mineral contents remarkably decrease in female patients with HIV-LD. How-ever, HIV-LD patients tend to have higher LM than non-LD patients. .