Vitamin D status in urinary calcium stone formation.

Serum vitamin D metabolites were measured in 160 normocalcemic urinary calcium stone formers and in 217 control subjects. No difference in concentrations of 25-hydroxy-vitamin D (25[OH]D), 24,25-dihydroxyvitamin D (24,25[OH]2D), and 1,25-dihydroxyvitamin D (1,25[OH]2D) was found between stone formers and control subjects. Values for 25(OH)D and 24,25(OH)2D were higher in hypercalciuric stone formers than in normocalciuric stone formers independent of seasonal fluctuation. No difference in concentration of serum 1,25(OH)2D was found between hypercalciuric and normocalciuric stone formers. No correlations were present between the serum concentrations of the measured vitamin D metabolites and of measures of calcium and phosphate metabolism. These findings suggest no major pathophysiologic role of the main vitamin D metabolites in urinary calcium stone formation.