Racial variation in gender frequency of calcium urolithiasis.

Calcium oxalate stones are known to occur most frequently in the fifth and sixth decades of life and in a male-to-female ratio of approximately 2:1. However, previous data are from predominantly white populations or from multiracial populations that have included patients with infection stones. We reviewed a population of 444 consecutive patients (189 white, 123 black and 132 Hispanic) from 1 urban hospital treated by shock wave lithotripsy for symptomatic renal and ureteral calculi, and added a population of 260 patients treated at a university hospital in Japan. Patients with infection stones and those with uric acid or cystine stones were excluded. We found men to be more commonly afflicted in the white (62%) and Asian (64%) populations but noted a reversal of gender frequency in the black and Hispanic populations, of which women comprised 68% and 60% of the stone population, respectively. We conclude that calcium urolithiasis is more common in women than previously reported, and discuss the possible etiologies.