Mixed Race Studies

Fracture Risk Assessment without Race/Ethnicity Information

The Journal of Clinical Endocrinology & Metabolism
Volume 97, Number 10 (2012-10-01)
pages 3593-3602
DOI: 10.1210/jc.2012-1997

Shinya Ishii
Department of Geriatric Medicine (S.I.)
Graduate School of Medicine
University of Tokyo

Gail A. Greendale
David Geffen School of Medicine
University of California, Los Angeles

Jane A. Caule
Graduate School of Public Health
University of Pittsburgh

Carolyn J. Crandall
David Geffen School of Medicine
University of California, Los Angeles

Mei-Hua Huang
David Geffen School of Medicine
University of California, Los Angeles

Michelle E. Danielson
Graduate School of Public Health
University of Pittsburgh

Arun S. Karlamangla
David Geffen School of Medicine
University of California, Los Angeles

Context: Dual-energy x-ray absorptiometry-derived bone mineral density (BMD) does not explain interracial differences in fracture risk; thus, BMD-based fracture risk assessment requires patient race/ethnicity information and ethnicity-specific BMD reference databases.

Objective: The objective of the study was to investigate whether composite femoral neck strength indices, which integrate dual-energy x-ray absorptiometry-derived femoral neck size, femoral neck BMD, and body size, will allow fracture risk assessment without requiring race/ethnicity information.

Design: This was a prospective cohort study.

Setting and Participants: A total of 1940 community-dwelling women aged 42–53 yr from four race/ethnicity groups (968 Caucasian, 512 African-American, 239 Japanese, and 221 Chinese) were followed up for 9 yr.

Outcome Measurements: Self-reported, nondigital, noncraniofacial fractures were measured.

Results: Two hundred and two women (10.4%) sustained fractures and 82 (4.3%) had minimum-trauma fractures. Each sd increment in any of the strength indices was associated with a 34–41% reduction in fracture hazard over 9 yr (each P < 0.001). Race/ethnicity predicted fracture hazard independent of BMD (P = 0.02) but did not predict fracture hazard independent of any of the composite indices (P = 0.11–0.22). Addition of race/ethnicity did not improve risk discrimination ability of the strength indices, but did significantly improve the discrimination ability of BMD. The discrimination ability of BMD with race/ethnicity was not statistically different from that of any of the strength indices without race/ethnicity.

Conclusions: Composite strength indices of the femoral neck can predict fracture risk without race/ethnicity information as accurately as bone mineral density does in combination with race/ethnicity information and therefore would allow risk prediction in people of mixed race/ethnicity and in groups without a BMD reference database.

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