BODY-SIZE ACCOUNTS FOR MOST DIFFERENCES IN BONE-DENSITY BETWEEN ASIANAND CAUCASIAN WOMEN

We compared bone mineral density (BMD) of the whole body (and subregio ns: arm, leg, and pelvis), hip, spine, lateral spine, wrist, and forea rm among Caucasian and Asian women at four geographic centers (Honolul u, HI; Nottingham, UK; Portland, OR; Copenhagen, Denmark). Data were d erived from the baseline examination of 1367 Caucasian and 162 Asian w omen enrolled in the 1609-subject Early Postmenopausal Interventional Cohort (EPIC) study. After adjusting for age, study site, years postme nopause, and years of estrogen use, BMD was approximately 4-6% lower ( P < 0.05) among Asian women at most skeletal sites, but there was no s ignificant difference for wrist or forearm BMD. Adding height, lean bo dy mass, fat mass, and/or quadriceps muscle strength to the regression models reduced the racial differences at most skeletal sites; after t hese additional adjustments, Asian women had significantly lower BMD o nly for the lateral spine (-4.4%; P < 0.005), arm (-2.20%; P < 0.05) a nd leg (-1.65%; P < 0.05), whereas the wrist was significantly greater (4.64%; P < 0.005) fur Asian women. Further research is needed to det ermine why racial differences in BMD persist at certain skeletal sites , but not others, after adjusting for body size.