Comparison of bone mineral content between Japan-born and US-born Japanese subjects in Hawaii.

The bone mineral content (BMC) of the calcaneus, and distal and proximal radius was measured by the single photon absorptiometric technique for 2307 US-born and 172 Japan-born subjects of Japanese ancestry living in Hawaii. The bone mineral content of the US-born subjects was greater than that of their Japan-born counterparts, on the average, by 8.8% at the calcaneus, 3.5% at the distal radius and 4.5% at the proximal radius. Differences between the two groups in height, weight, thiazide use, exercise (in men), estrogen therapy (in women), and calcium and vitamin D intake accounted for much of the difference in BMC between the US-born and Japan-born women, but less so for the men. Additional studies of BMC in migrant populations are needed to characterize further the environmental factors affecting bone mineral content.