Objective: To determine the association between race/ethnicity and bone mineral density (BMD) in women with systemic lupus erythematosus (SLE).
Methods: Women with SLE (n = 298), including 77 African Americans and 221 whites, completed this cross-sectional study conducted from 1996 to 2002. Hip and lumbar spine BMD were measured by dual-energy x-ray absorptiometry. Study participants completed a self-administered questionnaire and a physician completed the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). BMD results were expressed as Z scores. Analyses were performed to identify factors, including race/ethnicity, associated with low BMD defined as a Z score -1.0 or less at the hip or lumbar spine.
Results: African Americans compared with whites were younger at study visit (mean +/- SD 39.7 +/- 8.4 years versus 42.9 +/- 11.6 years) and had higher SDI (mean +/- SD 1.8 +/- 2.0 versus 1.0 +/- 1.6), but similar proportions of women were postmenopausal (31.2% versus 38.0%). African Americans had significantly lower mean BMD Z scores at the hip (-0.49 versus -0.07; group difference -0.41; 95% confidence interval [95% CI] -0.70, -0.13) and at the lumbar spine (-1.03 versus 0.10; group difference -1.13; 95% CI -1.48, -0.78) compared with whites. African American race/ethnicity was strongly associated with low BMD at the lumbar spine (adjusted odds ratio 4.42; 95% CI 2.19, 8.91) but not at the hip, adjusting for factors associated with low BMD.
Conclusion: African American women compared with white women with SLE had lower BMD at the hip and lumbar spine. African American race/ethnicity was associated with low BMD at the lumbar spine controlling for relevant clinical covariates.