The relationship between spinal and appendicular bone mass modified by physical, historical, and lifestyle factors

Spinal, radial, and calcaneal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and calcaneal bone mass measured by quantitative ultrasound densitometry (QUS) were compared in 83 healthy Japanese female volunteers. A significant and strong correlation was found within the same methods (r = 0.619 for lumbar spine and radius by DXA, r = 0.760 for lumbar spine and calcaneus by DXA, and r = 0.644 for calcaneus and radius by DXA), and within the same site (r = 0.758 for calcaneus by DXA and QUS). A lesser correlation was found when both the method and site were different (r = 0.521 for radius by DXA and calcaneus by QUS, and r = 0.583 for lumbar spine by DXA and calcaneus by QUS). Relations of spinal and appendicular bone mass were examined together with physical, historical, and lifestyle factors. Multiple correlation coefficients between bone mass at the lumbar spine and appendicular bone were 0.754 to 0.782, and all these increased after modification by physical, historical, and lifestyle factors in whichever appendicular bone. In the correlation between lumbar spine and radial BMD, past weight-bearing activity, age at menarche, family history of fractures, and body weight were chosen. Menstrual status, body weight, past weight-bearing activity, and present arm-using activity were chosen to determine the correlation between lumbar spine BMD and calcaneal bone mass by QUS. These results suggest that the incorporation of those factors improved the correlation between lumbar spine BMD and appendicular bone mass, especially in cases of lumbar spine BMD versus radial BMD or calcaneal bone mass by QUS.