2138 FRACTIONAL CALCIUM ABSORPTION AND HISTORY OF NEPHROLITHIASIS IN OLDER WOMEN IN THE STUDY OF OSTEOPOROTIC FRACTURES (2011)

You have accessJournal of UrologyStone Disease: Basic Research1 Apr 20112138 FRACTIONAL CALCIUM ABSORPTION AND HISTORY OF NEPHROLITHIASIS IN OLDER WOMEN IN THE STUDY OF OSTEOPOROTIC FRACTURES Mathew Sorensen, Brian Eisner, Katie Stone, Arnold Kahn, Li-Yung Lui, Natalia Sadetsky, and Marshall Stoller Mathew SorensenMathew Sorensen San Francisco, CA More articles by this author , Brian EisnerBrian Eisner Boston, MA More articles by this author , Katie StoneKatie Stone San Francisco, CA More articles by this author , Arnold KahnArnold Kahn San Francisco, CA More articles by this author , Li-Yung LuiLi-Yung Lui San Francisco, CA More articles by this author , Natalia SadetskyNatalia Sadetsky San Francisco, CA More articles by this author , and Marshall StollerMarshall Stoller San Francisco, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2349AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Intestinal absorption of calcium is known to play a critical role in hypercalciuric nephrolithiasis, a urinary metabolic defect present in up to 50% of calcium stone formers. A few small studies have used radioactive calcium to examine the association between intestinal calcium absorption and hypercalciuria, but no study has evaluated the association with nephrolithiasis. The purpose of this study was to evaluate the relationship between patient reported history of nephrolithiasis, fractional absorption of calcium, and the effect on bone mineral density (BMD). METHODS The Study of Osteoporotic Fractures (SOF) is a cohort of 9704 older women enrolled in 1986 and followed prospectively for more than 20 years. We performed secondary analyses of 7982 women who reported their kidney stone history and then presented in 1992, where 5452 patients (82%) underwent oral radioactive calcium assay (45Ca). We evaluated the relationship between nephrolithiasis, fractional calcium absorption and BMD. RESULTS Women with a history of nephrolithiasis had higher BMIs (p<0.01), and were less likely to currently use calcium supplements (p=0.02). For each 10% increase in fractional calcium absorption, there was a 30% (CI 12–51%, p<0.001) increased risk of nephrolithiasis. This risk was more pronounced (51%, CI 3–120%, p=0.03) among women that never supplemented calcium. Dietary calcium was not associated with nephrolithiasis. Among women that never used calcium supplements, there was a trend towards lower BMD in stone formers (p=0.07–0.13) at all sites except the spine. Women who used calcium supplements had similar BMD, regardless of nephrolithiasis history. After adjusting for age, BMI, health status, calcium supplementation and thiazide diuretic use, each 10% increase in fractional calcium absorption was associated with a 38% (CI 16–66%, p<0.001) increased risk of having a history of nephrolithiasis. CONCLUSIONS These data provide direct evidence that elevated intestinal calcium absorption is associated with an increased likelihood of historic nephrolithiasis. Women that supplemented calcium were less likely to have a history of nephrolithiasis, and had lower calcium absorption which may have prevented some of the decreased BMD seen in those with a history of nephrolithiasis. Although the mechanism remains to be established, these findings provide further evidence that calcium supplementation reduces the risk of nephrolithiasis; interventions to reduce intestinal calcium absorption may reduce the likelihood of nephrolithiasis. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e856 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mathew Sorensen San Francisco, CA More articles by this author Brian Eisner Boston, MA More articles by this author Katie Stone San Francisco, CA More articles by this author Arnold Kahn San Francisco, CA More articles by this author Li-Yung Lui San Francisco, CA More articles by this author Natalia Sadetsky San Francisco, CA More articles by this author Marshall Stoller San Francisco, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...