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Abstract: PO2613

Dietary Magnesium Intake, Risk of Kidney Stone, and Survival in the Women's Health Initiative (WHI)

Session Information

Category: Women’s Health and Kidney Diseases

  • 2000 Women’s Health and Kidney Diseases

Authors

  • Kota, Harshitha, Brown University, Providence, Rhode Island, United States
  • Wen, Xuerong, University of Rhode Island, Kingston, Rhode Island, United States
  • Chen, Chao, University of Florida, Gainesville, Florida, United States
  • Tang, Jie, Brown University, Providence, Rhode Island, United States
Background

The effect of dietary magnesium intake (DMI) on the risk of stone is controversial, and its effect on survival among kidney stone formers is unknown.

Methods

We examined participants enrolled in WHI, a prospective, longitudinal, multicenter study investigating the health of postmenopausal women, and used Cox regression analyses to determine the independent effects of DMI on the risk of incident kidney stone and survival amoungst the stone formers.

Results

145,942 participants were identified free of kidney stone history at baseline. 83% were Caucasian, mean age was 63. Among them, 6024 (4%) developed incident kidney stone during 1,601,750 person-years of follow up. The mean daily DMI was 318 mg, with 26% in tertile 1 (<241 mg), 41% in tertile 2 (241-348 mg) and 33% in tertile 3 (>348 mg). The incidence of kidney stone disease was 3.1, 3.3, and 3.9 per 1000 person-year in high, moderate and low DMI groups, respectively. The corresponding multivariable-adjusted hazard ratios were 0.82 (95% CI: 0.71-0.94) for high vs low DMI when dietary oxalate intake (DOI) is high, and 1.01 (95% CI: 0.81-1.26) for high vs low DMI when DOI is low.
Among incident stone formers, 82% were Caucasian, 23% were above age 70. Mean daily DMI was 304 mg, 32% in tertile 1, 38% in tertile 2, and 30% in tertile 3. Subsequently, 1346 (22%) died. Older age, histories of hypertension, diabetes and heart disease, low serum vitamin D, cigarette smoking, and hormone replacement associated significantly with mortality, p<0.05. However, DMI had no impact on mortality after adjusting for demographics and potential confounding factors, hazard ratio (HR) 0.91, 95% CI 0.73-1.14, p=0.4 when compared high DMI vs low DMI groups, HR 0.90, 95% CI 0.73-1.11, p=0.3 when compared medium DMI vs low DMI groups.

Conclusion

Our study suggests that higher DMI is associated with lower risk of incident kidney stone disease and this effect is modified by DOI. DMI does not appear to affect survival among post-menopausal women with incident kidney stone disease.

Funding

  • Clinical Revenue Support