Bone
-
Comparative Study
Effect of bone area on spine density in Chinese men and women in Taiwan.
Areal bone mineral density (BMD), the quotient of bone mineral content (BMC) divided by the projectional bone area (BA), measured with dual-energy X-ray absorptiometers (DXA), is the most common parameter used today to evaluate spinal osteoporosis. To evaluate whether gender, age, weight, and height can determine spinal BA, and to compare BA and analyze its effects on spinal density in the two genders, we measured BA and BMC, and calculated areal BMD, and the bone mineral apparent density (BMAD = BMD/the square root of BA) of the L-2 to L-4 vertebrae of 604 female and 223 male Chinese volunteers from 20 to 70 years of age using a Norland XR-26 DXA. Standardized for height and weight, BA showed a relatively large variation and a significant increase with increasing age in both genders. ⋯ Although taller body height, heavier weight, and increasing age were associated with a larger BA, these factors could not explain most of the interindividual variations in BA in both genders. Thus anteroposterior BA of lumbar vertebrae measured with DXA seems to affect the areal BMD and BMAD readings in the two genders. The larger BA caused a low BMAD and probably underestimated the true volumetric spine density in men.