Differences in bone mineral density between the right and left hips in postmenopausal women.

Bone mineral density (BMD) using dual energy radiography absorptiometry are commonly used for the diagnosis of osteoporosis. It is usually measured at the spine and also at one hip joint. Controversy still exists regarding the use of bilateral hip scanning. We analyzed the difference of BMD at bilateral hips in 384 postmenopausal women, retrospectively. The concordance and discordance rates of the lowest T-score and BMD between both hips were evaluated. The BMDs of the femoral neck and trochanter were significantly different between both hips (P < 0.05). There were also discrepancies between the lowest T-scores of both hips (P < 0.05). The discordance rates were about 30%. Due to significant differences in BMD between both hips at the femoral neck and trochanter and high discordance rate, bilateral hip measurements using DEXA are recommended to avoid underestimating osteoporosis.