Is there a difference between right and left femoral bone density?

Because of the known differences in bone mineral density (BMD) of the domin ant and nondominant forearms, it has been customary to measure BMD of the n ondominant forearm to reduce variance. However, it is less clear whether su ch systematic differences exist between BMD of the two hips. Accordingly, w e measured E-MD of both hips and the spine in 131 consecutive white women w ho presented to a community-based private practitioner for evaluation and a dvice on osteoporosis. There was a highly significant correlation between BMD of the two hips at t he femoral neck, trochanter, and Ward's triangle (r = 0.91, 0.93, and 0.89, respectively; p < 0.0001 for all three sites) and also between BMD at vari ous measurement sites in the hip and the spine BMD (p < 0.0001), Although t here was no significant difference between the right and left femoral neck BMD, there were small (approximately 1-2.5%) but significant differences be tween BMD of the two hips at the trochanter and Ward's triangle (p = 0.008 and 0.005, respectively). The left hip BMD was consistently higher than the right hip BMD at all measurement sites. Because of the small sample size o f left-handed persons, we were unable to determine the influence of dominan t handedness on hip BMD. We concluded the following: (1) BMDs of the two hi ps are highly correlated at relevant measurement sites; (2) there does not appear to be a dominant hip as there is dominant forearm; (3) because of st rong agreement between BMD of the two hips, there is little justification t o measure both hips in routine clinical practice.