Vitamin D repletion does not alter urinary calcium excretion in healthy postmenopausal women

Abstract

We excluded women with a history of urolithiasis and kidney disease. Women had one calcium absorption study when vitamin D-insufficient, received vitamin D therapy, and completed a second calcium absorption study when vitamin D-replete. We fed subjects meals that mirrored the nutrient composition from self-reported 7-day diet diaries. To measure calcium absorption, we collected urine for 24 h during both visits. RESULTSWe achieved vitamin D repletion in all women (25(OH)-vitamin D before and after treatment, 22 and 63 mg/dL, respectively; P < 0.001). The mean calcium intake was 832 mg/day. Residual urine specimens were available for 16 women, allowing a measurement of 24-h urinary calcium. Calcium excretion did not change after vitamin D therapy (212 before vs 195 mg/ day after; P = 0.60). Of four women with hypercalciuria ( > 247 mg/day), calcium excretion decreased in three (377-312 mg/ day, not significant). CONCLUSION SUBJECTS AND METHODSWe recruited 18 women at ≥ 5 years after menopause who had vitamin D insufficiency (serum 25(OH)-vitamin D, 16-24 mg/dL).

Vitamin D Status in Patients with Recurrent Kidney Stones

“…Intriguing is the finding that 25(OH)D levels did not correlate with hypercalciuria. This is compatible with recent literature [5] showing that vitamin D optimization did not increase urinary calcium excretion in a population that is prone to lithogenesis. Although these results should be considered preliminary, they provide an important insight into vitamin D status in stone formers and should prompt further study.…”

“…Indeed, it has been shown that a high serum concentration of 1,25-dihydroxyvitamin D (1,25(OH) 2 D) [3] and administration of the synthetic active vitamin D analogue (dihydrotachysterol) [4] contribute to stone formationby increasing intestinal calcium absorption and subsequent urinary calcium excretion. However, recent literature [5] among healthy postmenopausal women (considered to be prone to lithogenesis)showed benefit from their serum vitamin D optimization without increasing the risk of calcium stone formation.…”

Safety and Efficacy of Weekly 30,000 IU Vitamin D Supplementation as a Slower Loading Dose Administration Compared to a Daily Maintenance Schedule in Deficient Patients: A Randomized, Controlled Clinical Trial

“…vitamin D repletion itself in general does not alter urinary calcium excretion, despite increased calcium absorption. Since calcium excretion did not change after vitamin D therapy applied supplementation can be provided also to postmenopausal women who are not stone-formers and who are vitamin D insufficient, without fear of increased risk of nephrolithiasis [41].…”

CUA guideline on the evaluation and medical management of the kidney stone patient ‒ 2016 update

“…In patients with vitamin D insufficiency, calcium excretion did not change with vitamin D repletion based on 24-hour collections, and in some patients, it decreased. 69 A randomized, double-blind, placebo-controlled study of high doses of vitamin D daily did not change urinary calcium excretion in healthy volunteers. 70 Further investigators randomized 163 patients to vitamin D vs. placebo.…”