2099 A NOVEL FOOD FREQUENCY QUESTIONNAIRE FOR STONE FORMERS ACCURATELY ASSESSES SPECIFIC NUTRITIONAL LITHOGENIC RISK FACTORS

Abstract

INTRODUCTION AND OBJECTIVES: Certain 24-h urinary parameters can predict or give clues to nutritional risk factors for lithogenesis. However, renal excretion is not always reflective of diet due to differential homeostatic handling and metabolism of certain parameters. Moreover, patients may alter their habitual dietary habits during 24-h urine collections. Therefore, interpretation of 24-h urine results is not a surrogate for nutrition assessment of patients’ nutrition and dietary patterns. Because many urologists do not have access to a registered dietitian (RD), a novel self-administered food frequency questionnaire (FFQ) was developed to identify major nutrition-related lithogenic risk factors. METHODS: A 33-item pilot FFQ was developed by RDs to quantify intake of stone inhibitors (fruits, vegetables, and fluids), stone promoters (meats and sodium), and calcium. A convenience sample of healthy adults (n 18; M:F, 2:16; age 18-50 y) were recruited to complete the FFQ and undergo a telephone-administered, RD-assisted 24-h recall the following day. To evaluate performance of the pilot FFQ, subject’s FFQ responses were compared to nutrient analysis of their diet recall. RESULTS: The FFQ required an average of 5 minutes to complete and agreed favorably with the 24-h assisted recall in most categories. The FFQ assessed subjects’ mean daily fruit and vegetable intake within 0.5 serving (10%) of the recall. Fluid intake was equally well-captured on the FFQ (r 0.71; correlation confirmed, p 0.005) with a minimal (8 oz) under-reporting on the FFQ vs. the recall. The Pearson correlation coefficient was highest for meats (r 0.78); however, subjects over-reported meats on the FFQ by nearly 2 servings per day (p 0.003 for difference from recall), suggesting modifications to the FFQ would improve its accuracy in assessing meat intake. Calcium and sodium intakes, calculated on the FFQ as mg/d, were within 236 and 320 mg, respectively, of subjects’ actual intake as quantified by nutrient analysis of the 24-h diet recall. CONCLUSIONS: As the parameters reported in patients’ 24-h urine analyses are not perfect surrogates for intake, nutrition assessment and diagnosis of diet-related risk factors is needed. For urologists who lack a qualified nutrition professional on their care team, our pilot FFQ holds promise as a quick and accurate tool to aid in the identification of specific stone-related nutrition factors. Data from this pilot study clarify areas for modification of the FFQ and suggest that validation studies in the target population will confirm its utility in the clinic setting.