CalciumKidney DiseaseVitamin D

Risk of kidney stones with calcium and vitamin D

The Women’s Health Initiative reported a 17% excess in urinary tract stone formation with calcium + vitamin D supplements.

Now, researchers in the US evaluated whether this risk might be modified by certain patient characteristics.

First, the details.

  • 7 years of records from 36,282 postmenopausal women  were reviewed.
  • Treatment was 500 mg calcium carbonate + 200 IU vitamin D3 twice daily or matching placebo.
  • The incidence of urinary tract stones was determined.

And, the results.

  • The incidence of self-reported and clinically diagnosed urinary tract stones was more common in the calcium + vitamin D group than in the placebo group.
    • 449 women in the calcium + vitamin D group and 381 women in the placebo group reported a stone.
  • Demographic, anthropomorphic (body type), dietary, and other hypothesized risk factors had no measurable effect.
  • Neither the total calcium intake nor the use of calcium supplements at the start of the study was associated with the risk of stones.

The bottom line?

The authors concluded, “Daily supplementation with calcium + vitamin D for 7 years was associated with an increase in the number of self-reported urinary tract stones.”

The findings suggest that despite the widespread prevalence of vitamin D deficiency, treatment should be undertaken with care and with medical supervision.

6/20/11 21:03 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.