The relationship between urinary stone components and visceral adipose tissue using computed tomography-based fat delineation

Objective To determine the relationship between body mass index (BMI), visceral adipose tissue (VAT), and stone components. Methods A cross-sectional study has been done for urinary stone cohort between 2010 and 2012. Data on patient's age, gender, BMI, urinary pH, stone components, and VAT using computed tomography-based delineation were collected. Obesity was defined as BMI ≥ 25 kg/m² or as VAT ≥ 100 cm². To compare the differences between the types of stones, multinomial logistic regression analyses were conducted. Results Of 203 cases, 49.3% patients were obese based on BMI, and 65.5% were obese using VAT criteria. Multinomial logistic regression analysis revealed that obesity defined by VAT was found to be associated with uric acid stones compared with calcium phosphate stones (odds ratio [OR] 6.544, 95% confidence interval [CI], P =.030) and mixed calcium oxalate phosphate stones (OR 5.582, 95% CI, P =.038). Similar results were observed in calcium oxalate stones over calcium phosphate stones (OR 2.984, 95% CI, P =.032) and calcium oxalate phosphate stones (OR 2.542, 95% CI, P =.041). On the contrary, obesity defined based on BMI has no correlation over all types of urinary stone components. Conclusion This result implies that VAT has a more important role in uric acid and calcium oxalate stone formation than total body fat, represented by BMI.