The USDA Automated Multiple-Pass Method accurately assesses population sodium intakes

Background: Given current sodium-reduction strategies, accurate and practical methods to monitor sodium intake in the US population are critical. Although the gold standard for estimating sodium intake is the 24-h urine collection, few studies have used this biomarker to evaluate the accuracy of a dietary instrument. Objective: Our objective was to compare self-reported dietary intake of sodium with 24-h urinary excretion obtained in the USDA Automated Multiple-Pass Method (AMPM) Validation Study. Design: Subjects were healthy, weight-stable volunteers aged 30-69 y recruited from the Washington, DC, area. Data from 465 subjects who completed at least one 24-h recall and collected a complete 24-h urine sample during the same period were used to assess the validity of sodium intake. Reporting accuracy was calculated as the ratio of reported sodium intake to that estimated from the urinary biomarker (24-h urinary sodium/0.86). Estimations of sodium intake included salt added in cooking but did not include salt added at the table. Results: Overall, the mean (95% Cl) reporting accuracy was 0.93 (0.89, 0.97) for men (n = 232) and 0.90 (0.87, 0.94) for women (n = 233). Reporting accuracy was highest for subjects classified as normal weight [body mass index (in kg/m(2)) <25]: 1.06 (1.00, 1.12) for men (n = 84) and 0.99 (0.94, 1.04) for women (n = 115). For women only, reporting accuracy was higher in those aged 50-69 y than in those who were younger. Conclusion: Findings from this study suggest that the USDA AMPM is a valid measure for estimating sodium intake in adults at the population or group level. Am J Clin Nutr 2013;97:958-64.