Urinary tract stone occurrence in the Women's Health Initiative (WHI) randomized clinical trial of calcium and vitamin D supplements
Wallace RB, Wactawski-Wende J, O'Sullivan MJ, Larson JC, Cochrane B, Gass M, et al.
Published in Am J Clin Nutr, Vol. 94 (1), pp. 270-7
Methodology
Secondary analysis of the Women's Health Initiative randomised, placebo-controlled trial: 36,282 postmenopausal women aged 50-79 took 500 mg calcium (as calcium carbonate) plus 200 IU vitamin D3 twice daily (1,000 mg and 400 IU a day) or placebo for an average of 7.0 years; self-reported, clinically diagnosed urinary tract stones were the outcome.
Key Findings
Stones were more common with calcium plus vitamin D than with placebo (449 vs 381 women; HR 1.17, 95% CI 1.02 to 1.34). The excess did not differ by demographic, dietary or other risk factors, and neither total calcium intake nor calcium supplement use at baseline predicted stones. Censoring women below 80% adherence gave similar results.
Conclusions
Seven years of daily calcium plus vitamin D was associated with more self-reported urinary tract stones.
Limitations
Stones were self-reported; calcium and vitamin D were given together, so their separate effects cannot be told apart; the abstract does not say whether tablets were taken with meals; women only.
Supplements Studied
associated with an increase in the number of self-reported urinary tract stones
Related Health Concerns
Study Details
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