Effect of hand dominance on bone mass measurement in sedentary individuals

The aim of this study was to determine in healthy sedentary subjects the ef fect of hand dominance on side-to-side difference in bone area and bone mas s for upper and lower extremities. Dual-energy X-ray absorptiometry (DXA) m easurements of both forearms and hips were performed on 193 right-handed an d 20 left-handed subjects as determined by self-report. Scan acquisition an d scan analyses were performed by one investigator, but all scan pairs were independently assessed for symmetry of positioning and movement artifacts by three investigators. Results show that DXA measurements between sides ma y be highly correlated regardless of the symmetry of the scan pair. However asymmetric DXA scan pairs may have more than twice the side-to-side differ ence found in symmetric DXA scan pairs at the hip. Side-to-side differences between subregions were greater than the differences between measurements at the total radius, ulna, or hip. For symmetric pairs of DXA scans, the do minant forearm has significantly higher bone area and bone mineral content (BMC). Bone mineral density (BMD) was significantly higher only in the ulna of the dominant forearm. However, the nondominant forearm has higher value s than dominant forearm in at least one DXA measurement in >24% of the subj ects. There were no significant differences in any DXA measurements between hips, and higher DXA measurements did not occur significantly more frequen tly at the hip corresponding to the dominant hand. We conclude that healthy sedentary subjects tend to have proportionally higher bone area and BMC in the dominant forearm that results in similar BMD between dominant and nond ominant forearms. This relationship does not appear to be applicable to mea surements at the hip. In addition, there is a significant proportion of sub jects with higher bone area and BMC in the nondominant extremities. Thus, i n sedentary subjects, the consistency in the use of same extremity and the consistency in scan acquisition techniques and scan analyses is of greater importance than the selection of an extremity based on hand dominance in DX A studies.