Comparison of Urinary Lithogenic Risk Factors According to Age and Sex in Stone Formers

Lee, Gyoung Gyou; Lee, Sang Cheol; Kim, Wun Jae

Abstract

PURPOSE
The present study was performed to assess differences of urinary risk factors for urolithiasis according to age, in men and women stone formers.
MATERIALS AND METHODS
This study comprised 599 patients who presented consecutively with one or more episodes of urinary stone from September 1997 to January 2000. They were divided into 4 groups by stratified age, consisting of group 1 (104 patients) aged <30 years, group 2 (181) aged 30-39 years, group 3 (135) aged 40-49 years, and group 4 (179) aged > =50. Twenty-four hour urinary parameters including total volume, and levels/concentrations/expressions of sodium, uric acid, creatinine, phosphorus, calcium, magnesium, oxalate and citrate, as well as frequencies of metabolic abnormalities, were compared among the 4 groups in each sex.
RESULTS
For men, urinary sodium excretion was significantly lower in group 4 and citrate excretion was significantly lower in group 1 than in the other groups. For women, the excretion of citrate in group 2 was significantly higher than in the other groups and phosphorus excretion in group 4 was significantly lower than in the other groups. When the frequencies of metabolic abnormalities were compared, hypocitraturia of groups 1 and 2, and lower hypernatriuria and higher hypomagnesuria of group 4 were noted among men. The men in group 4 had significantly lower frequencies of metabolic abnormalities. Except for the lower frequency of hyperuricosuria in group 1, no significant differences of metabolic abnormalities were found among the female groups.
CONCLUSIONS
Although multiple lithogenic factors can be responsible for urolithiasis, this study showed that hypocitraturia was the most important risk factor and could play the vital role in stone development, especially in young men and elderly women.