Pd35-08 can the Inflammatory Potential of Diet Rather Than the Individual Dietary Components Discriminates Between Calcium Oxalate Renal Stone Patients and Healthy Controls?

Abstract

INTRODUCTION AND OBJECTIVE: Many studies have investigated the relationship between individual food groups and the risk of urolithiasis focusing on how diet influences the urinary risk factors for CaOx supersaturation and crystallization. However, diet also can play an important role in regulating chronic inflammation but what is lacking is a quantitative measure for assessing the inflammatory potential of an individual's diet and whether such a measure is correlated with stone risk. The Dietary Inflammatory Index (DIIÒ) is an analytical tool which provides such a measure. The aim of this study is to test the hypothesis that the inflammatory potential of habitual diet is higher in renal stone formers than in normal controls.METHODS: A total of 97 stone formers (SFs) and 63 controls (Cs), matched on age (AE 5 years) and sex completed a semiquantitative food frequency questionnaire from which nutrient composition was computed. These data were used to calculate the Dietary Inflammatory Index (DIIÒ),which evaluates the inflammatory potential of the diet according to the pro-and anti-inflammatory properties of its components. To control the effect of energy intake, energy-adjusted DII (E-DIIÒ) scores were calculated. A single blood sample was obtained from each participant (n[160), and two consecutive overnight (8h) urine samples were collected from a subset of these (n[59 SFs and n[54 Cs). Samples were analysed for stone risk factors. Data were analysed using descriptive statistics and logistic and linear regression models.RESULTS: DII and E-DII values were significantly more positive (i.e., more pro-inflammatory) in cases (-0.7 and -0.3) than in controls (-2.6 and -1.7), p<0.0001 and p<0.0001 respectively. Significant negative correlations were seen between E-DII score and blood HDL cholesterol (p[0.03) and urine volume (p[0.003), While significant positive correlations were seen between E-DII and urine concentrations of calcium (p[0.02), phosphate (p<0.0001), magnesium (p<0.0001) and uric acid (p[0.004).CONCLUSIONS: Our results show, for the first time, that holistic evaluation of the inflammatory potential of the whole diet rather than that of individual dietary components, can differentiate between SFs and Cs, thereby demonstrating the importance of pro-inflammatory diets in stone pathogenesis. As such, our study provides a compelling argument for determining DII/ E-DII scores in lithogenic patients on presentation and after dietary intervention, as part of their routine work-up.