The Relationship between Obesity and the Risk Factors of Urolithiasis

Abstract

Purpose: The aim of this study was to assess the relationship between obesity and the metabolic risks factors for urolithiasis. Materials and Methods: We performed stone metabolic studies on urolithiasis patients (306 men, 175 women) who were without medical or dietetical pretreatment between January 2002 and July 2006, and we classified them as being of low weight (body mass index; BMI: <18.5, 5 men, 10 women), normal weight (BMI: 18.5-24.9, 149 men, 96 women), overweight (BMI: 25-29.9, 136 men, 60 women) or obese (BMI≥30, 16 men, 9 women). Results: There was a statistically significant difference in the prevalence of obesity between the urolithiasis group and the control group (p<0.05). The correlation analysis revealed a significant positive relationship between BMI and the serum calcium, uric acid, urinary calcium, uric acid and citrate, and there was an inverse relationship between BMI and urinary pH (p<0.05). The frequency of urinary stone risk factors was increased with BMI (p<0.05). Conclusions: The positive correlation between BMI and the risk factors for urolithiasis was revealed. Therefore, we need to prospectively study the relationship between obesity and the risk factors, which will help to understand the mechanism of urolithiasis about obesity. (Korean J Urol 2007;48:505-511)