Bone mineral density of recent African immigrants in the United States.

Background: Racial/ethnic difference in bone mineral density (BMD) exists. The underlying mechanism is unclear and needs investigation.

Purpose: To determine BMD and its relation to environmental exposure in recent African immigrants.

Methods: BMD in recent sub-Saharan Sudanese immigrants (55 men and 88 premenopausal women) in the United States was measured. Analysis of covariance (ANCOVA) model was performed, with total body, spine and hip BMD as dependent variables; and sex, age, body weight, the length of stay in the United States, and milk intake as independent variables.

Results: BMD Z score in the spine but not total body or hip in the Sudanese immigrants was significantly lower compared with the normative values of African Americans and Caucasians. Total body and hip BMD was positively correlated (p < 0.015) with their length of stay in the United States. Hip BMD was significantly correlated with milk intake (p < 0.02) and marginally (p = 0.052) with their length of stay in the United States, independent of body weight.

Conclusions: Spinal BMD was significantly lower in recent Sudanese immigrants than in African Americans or Caucasians. Their hip and total body BMD was associated with their length of stay in the United States, suggesting a potential environmental factors in the ethnic diversity of BMD.