Bone density in an immigrant population from Southeast Asia

The epidemiology of bone loss in populations of Asian heritage is still poorly known. This study compared the skeletal status of a convenience sample of 396 Southeast Asian immigrants (172 Vietnamese, 171 Cambodians and 53 Laotians) residing in Rochester, Minnesota in 1997 with 684 white subjects previously recruited from an age-stratified random sample of community residents. Areal bone mineral density (BMD, g/cm2) and volumetric bone mineral apparent density (BMAD, g/cm3) were determined for lumbar spine and proximal femur using the Hologic QDR 2000 instrument for the white population and the QDR 4500 for Southeast Asian subjects; the machines were cross-calibrated from data on 20 volunteers. Lumbar spine BMD was 7% higher in white than Southeast Asian women (p < 0.001), and similar results were observed for the femoral neck; lumbar spine BMD was 12% higher in white than nonwhite men (p < 0.001). Race-specific discrepancies were reduced by calculating BMAD: for premenopausal women, lumbar spine and femoral neck differences between whites and Southeast Asians were eliminated; for postmenopausal women the lumbar spine differences persisted (p < 0.0001), while femoral neck BMAD was actually higher for Southeast Asians. There were no race-specific differences in femoral neck BMAD among men of any age (p = 0.312), but lumbar spine BMAD was less for younger (p = 0.042) but not older (p = 0.693) Southeast Asian men. There were differences among the Southeast Asian subgroups, but no clear pattern emerged. Predictors of lumbar spine BMAD in Southeast Asian women were age (p < 0.001), weight (p = 0.015) and gravidity (p = 0.037). Even after adjusting for bone size using BMAD, 32% and 9% of Southeast Asian women and men, respectively, would be considered to have osteoporosis at the femoral neck and 25% and 4%, respectively, at the lumbar spine. These findings indicate a need for culturally sensitive educational interventions for Southeast Asians and for physicians to pursue diagnosis and treatment to prevent osteoporosis-related disabilities in this population.