VDR and urolithiasis: The meta-analysis of the VDR gene involving 5 studies with a total of 1672 allele frequency in recurrent stone formers and 1286 allele frequency in controls, also showed a significant association with recurrent urolithiasis (Fig. 3, overall OR = 1.22, CI 95% = 1.05–1.42, p = 0.03).