Quantification of bone mineral content using dual-photon absorptiometry in a normal Japanese population.

The bone mineral content of lumbar spine and/or total body were quantified in 217 healthy Japanese (86 males and 131 females) using a Dichromatic Bone Densitometer (Norland Corp., Model 2600). The bone mineral density of the third lumbar vertebra (L3 BMD) decreased significantly after age 20 in males (r = -0.417, p less than 0.0002), with acceleration of the decrease after age 50 (r = -0.621, p less than 0.00002). A significant correlation was found between L3 BMD and age after age 40 (r = -0.747, p less than 0.0001) in females. L3 BMD correlated with both the body height (r = 0.335, p less than 0.0001) and the body weight (r = 0.340, p less than 0.0001). Total bone mineral content from the second to fourth lumbar vertebrae correlated significantly with total body bone mineral (r = 0.880, p less than 0.00001) in these normal subjects. Lumbar spine bone mineral as measured by dual-photon absorptiometry is lower in Japan than the bone mass in the United States, although not lower than in other parts of the world.