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Serum 25 Hydroxyvitamin (OH)D and Clinical Fracture Risk in a Multiethnic Cohort of Women: The Women’s Health Initiative (WHI)

Jane A. Cauley, M. Danielson, R. Boudreau, Kamil E. Barbour, M. Horwitz, D. Bauer, K. Ensrud, J. Manson et al.

Journal of Bone and Mineral Research, 2011

400 participants · 139 citations

Abstract

Low 25‐hydroxyvitamin D [25(OH)D] levels have been linked to hip fracture in white women. To study the association of 25(OH)D with risk of fracture in multiethnic women, we performed a nested case‐control study within the prospective Women's Health Initiative (WHI) Observational Study. Incident fractures were identified in 381 black, 192 Hispanic, 113 Asian, and 46 Native American women over an average of 8.6 years. A random sample of 400 white women who fractured was chosen. One control individual was selected per case and matched on age, race/ethnicity, and blood draw date. 25(OH)D, parathyroid hormone, and vitamin D–binding protein (DBP) were measured in fasting baseline serum. Conditional logistic regression models were used to calculate the odds ratio (OR) and 95% CI. In multivariable models, higher 25(OH)D levels compared with levels less than 20 ng/mL were associated with a lower risk of fracture in white women (20 to <30 ng/mL: OR = 0.82, 95% CI 0.58–1.16; ≤30.0 ng/mL: OR = 0.56, 95% CI 0.35–0.90; p trend = 0.02). In contrast, higher 25(OH)D (≥20 ng/mL) compared with levels less than 20 ng/mL were associated with a higher risk of fracture in black women (OR = 1.45, 95% CI 1.06–1.98; p trend = 0.043). Higher 25(OH)D (≥30.0 ng/mL) was associated with higher fracture risk in Asian women after adjusting for DBP (OR = 2.78, 95% CI 0.99–7.80; p trend = 0.04). There was no association between 25(OH)D and fracture in Hispanic or Native American women. Our results suggest…

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Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 400 participants or records.

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