Magnesium intake, bone mineral density, and fractures: Results from the Women's Health Initiative Observational Study

Tonya S. Orchard, Joseph C. Larson, Nora Alghothani, Sharon Bout-Tabaku, Jane A. Cauley, Zhao Chen, Andrea Z. LaCroix, Jean Wactawski-Wende, Rebecca D. Jackson

Research output: Contribution to journalArticle

82 Scopus citations

Abstract

Background: Magnesium is a necessary component of bone, but its relation to osteoporotic fractures is unclear. Objective: We examined magnesium intake as a risk factor for osteoporotic fractures and altered bone mineral density (BMD). Design: This prospective cohort study included 73,684 postmenopausal women enrolled in the Women's Health Initiative Observational Study. Total daily magnesium intake was estimated from baseline food-frequency questionnaires plus supplements. Hip fractures were confirmed by a medical record review; other fractures were identified by self-report. A baseline BMD analysis was performed in 4778 participants. Results: Baseline hip BMD was 3% higher (P < 0.001), and whole-body BMD was 2% higher (P < 0.001), in women who consumed >422.5 compared with <206.5 mg Mg/d. However, the incidence and RR of hip and total fractures did not differ across quintiles of magnesium. In contrast, risk of lower-arm or wrist fractures increased with higher magnesium intake [multivariate-adjusted HRs of 1.15 (95% CI: 1.01, 1.32) and 1.23 (95% CI: 1.07, 1.42) for quintiles 4 and 5, respectively, compared with quintile 1; P-trend = 0.002]. In addition, women with the highest magnesium intakes were more physically active and at increased risk of falls [HR for quintile 4: 1.11 (95% CI: 1.06, 1.16); HR for quintile 5: 1.15 (95% CI: 1.10, 1.20); P-trend < 0.001]. Conclusions: Lower magnesium intake is associated with lower BMD of the hip and whole body, but this result does not translate into increased risk of fractures. A magnesium consumption slightly greater than the Recommended Dietary Allowance is associated with increased lower-arm and wrist fractures that are possibly related to more physical activity and falls. This trial was registered at clinicaltrials.gov as NCT00000611.

Original languageEnglish (US)
Pages (from-to)926-933
Number of pages8
JournalAmerican Journal of Clinical Nutrition
Volume99
Issue number4
DOIs
StatePublished - Apr 1 2014

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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    Orchard, T. S., Larson, J. C., Alghothani, N., Bout-Tabaku, S., Cauley, J. A., Chen, Z., LaCroix, A. Z., Wactawski-Wende, J., & Jackson, R. D. (2014). Magnesium intake, bone mineral density, and fractures: Results from the Women's Health Initiative Observational Study. American Journal of Clinical Nutrition, 99(4), 926-933. https://doi.org/10.3945/ajcn.113.067488