Vitamin B6 intake and the risk of incident kidney stones
Higher vitamin B6 intake might reduce urinary excretion of oxalate, one of the major determinants of risk for calcium oxalate kidney stones. Previous studies investigating the association between intake of vitamin B6 and risk of stones found conflicting results. We sought to investigate the association in three large prospective cohorts. We prospectively examined the association in the Health Professionals Follow-up Study (HPFS; n = 42,919 men), Nurses’ Health Study I (NHS I; n = 60,003 older women), and Nurses’ Health Study II (NHS II; n = 90,629 younger women). Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident stones across categories of total vitamin B6 intake (<3.0, 3.0–4.9, 5.0–9.9, 10.0–39.9, ≥40.0 mg/day) were generated with Cox proportional hazards regression models adjusted for potential confounders. During 3,316,846 person-years of follow-up, 6576 incident kidney stones were confirmed. In univariate and multivariate analyses, there was no association between intake of vitamin B6 and incident stones. The HR for stones in the highest category compared with the lowest was 1.05 (95% CI 0.85, 1.30; p value for trend = 0.61) for HPFS, 0.95 (95% CI 0.76, 1.18; p value for trend = 0.42) for NHS I, and 1.06 (95% CI 0.91, 1.24; p value for trend = 0.34) for NHS II. The pooled adjusted HR for the highest category compared with the lowest was 1.03 (95% CI 0.92, 1.15; p value for trend = 0.60). Intake of vitamin B6 is not associated with risk of incident kidney stones.
KeywordsCohort studies Nutrition Urolithiasis Vitamin B6
Body mass index
Food frequency questionnaire
Health Professionals Follow-up Study
Nurses’ Health Study
PMF, ENT, GG and GCC designed research; PMF, ENT and GCC conducted research; PMF analyzed data; PMF, ENT, GG and GCC wrote the paper; PMF and GCC had primary responsibility for final content. All authors read and approved the final manuscript.
Compliance with ethical standards
Supported by research Grants from the National Institutes of Health: DK094910, DK91417, CA186107, CA176726 and CA167552.
Conflict of interest
GCC: Consultant: Allena Pharmaceuticals, AstraZeneca, Exponent; Royalties: UpToDate (author and Section Editor); Honorarium: American Society of Nephrology (Editor-in-Chief, Clinical Journal of the American Society of Nephrology). PMF received consultant fees from BioHealth Italia. All other authors have nothing to disclose.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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