VASECTOMY IS ASSOCIATED WITH AN INCREASED RISK FOR UROLITHIASIS

We evaluated vasectomy as a potential risk factor for urolithiasis. Va sectomy is a common method of contraception among otherwise healthy me n. This is also the population at highest risk for urolithiasis. We co nducted a case-control study of patients in a large prepaid health mai ntenance organization, Cases were men experiencing initial episodes of urolithiasis, ascertained by reviewing radiology logs and medical rec ords. The age-matched controls were men with no history of urolithiasi s. In logistic regression models, the relative risk of urolithiasis fo r men with vasectomies compared with men without vasectomies was 1.9 f or men younger than 46 years of age (95% confidence interval = 1.2 to 3.1, P = 0.005), and the relative risk was 0.9 (95% confidence interva l = 0.5 to 1.5, P > 0.8) for men who were at least 46 years old. The r elative risk of urinary calculi was 2.0 (95% confidence interval 1.0 t o 4.1, P < 0.05) for men with vasectomies 0 to 4 years before evaluati on compared with men without vasectomies, and the excess risk persiste d as long as 14 years postvasectomy. Vasectomy was associated with a t wofold increased risk for urolithiasis in men younger than 46 years of age, This increased risk may persist for up to 14 years postvasectomy . Given the large number of men who undergo vasectomy worldwide each y ear, the increased risk for urolithiasis among vasectomized men may re sult in substantial excess morbidity. (C) 1997 by the National Kidney Foundation, Inc.