Background: The incidence of urolithiasis is twofold to threefold higher in men than in women. Several animal studies have suggested an association between testosterone levels and the formation of kidney stones. Specifically, castration has been shown to decrease stone formation in rat models. The association between testosterone and stone formation in humans, however, has not been well investigated.
Patients and methods: Early morning total and free testosterone levels were recorded for 55 male patients. Participants completed a demographics questionnaire, and clinical records of enrolled subjects were reviewed. When available, stone composition was determined in the stone formers. Mann-Whitney tests and logistic regression models were used to examine the data.
Results: Of the 55 patients, 25 had no history of urolithiasis and 30 had a history of urolithiasis. Although the differences between the two groups were not statistically significant, the stone formers compared with stone-free controls tended to be older (median age 48.4 vs 36.5 years, P = 0.072) and have higher serum levels of testosterone (median serum concentration 384 vs 346 ng/dL, P = 0.112). In the multivariate analyses, after adjusting for age and body mass index, the testosterone-related odds ratio was 1.004 with a corresponding P value 0.051.
Conclusions: Male stone formers were found to have higher serum total testosterone levels compared with a similar cohort without stones. This result is consistent with several animal models that have demonstrated that testosterone is a risk factor for stone formation. Our findings warrant confirmation in a larger, prospective study. There are potential therapeutic implications if testosterone is found to be a risk factor in urolithogenesis.