The U.S. Department of Agriculture Automated Multiple-Pass Method accurately assesses sodium intakes

Authors: Rhodes, Donna; Murayi, Theophile; Clemens, John; Baer, David; Sebastian, Rhonda; Moshfegh, Alanna

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2013
Publication Date: 5/1/2013
Citation: Rhodes, D.G., Murayi, T., Clemens, J.C., Baer, D.J., Sebastian, R.S., Moshfegh, A.J. 2013. The U.S. Department of Agriculture Automated Multiple-Pass Method accurately assesses sodium intakes. American Journal of Clinical Nutrition. 97:958-964.

Interpretive Summary: Accurate and practical methods to monitor sodium intake of the U.S. population are essential given current sodium reduction strategies. The gold standard for estimating sodium intake is the 24 hour urine collection given that it is widely assumed that sodium intake is difficult to accurately measure from food intake data. As few studies have used 24 hour urines to evaluate the accuracy of a dietary intake method, the objective of this research was to compare self-reported dietary intake of sodium to 24 hour urinary excretion in the USDA Automated Multiple-Pass Method (AMPM) Validation Study. Using data from 472 subjects, sodium intake collected from two 24 hour dietary recalls using the AMPM was compared to sodium urinary excretion from two 24 urine collections obtained during the same days as the recalls. Results show that the USDA AMPM is an accurate method for collecting dietary intakes for the population. The AMPM is used to collect dietary data in What We Eat In America, NHANES. Data, from this continuous national survey which collects two days of dietary data on about 5,000 participants each year, are to be used to ensure and enhance monitoring and surveillance relative to sodium intake measurement in the U.S. population.

Technical Abstract: Accurate and practical methods to monitor sodium intake of the U.S. population are critical given current sodium reduction strategies. While the gold standard for estimating sodium intake is the 24 hour urine collection, few studies have used this biomarker to evaluate the accuracy of a dietary instrument. The objective of this research was to compare self-reported dietary intake of sodium to 24 hour urinary excretion obtained in the USDA Automated Multiple-Pass Method (AMPM) Validation Study. The AMPM, used to collect 24 hour recalls in What We Eat In America, NHANES was validated in a large doubly-labeled water study and shown to reduce bias in the collection of energy intakes in a study population that included 524 volunteers, ages 30-69 years. Using data from subjects (n=472) who completed at least one 24 hour recall plus collected a complete 24 hour urine during the same period, the validity of sodium intake was assessed. Reporting accuracy was calculated as the ratio of reported intake to that estimated from the urinary biomarker (24 hour urinary Na/0.86). Estimations of sodium intake included salt added in cooking but did not include salt added at the table. Mean (95%CI) reporting accuracy was 0.92 (0.88, 0.96) for men (n= 239) and 0.91 (0.86, 0.94) for women (n=233). In conclusion, the AMPM is a valid measure for estimating sodium intakes at the group level provided food composition databases are routinely updated to reflect changes in the sodium content of foods consumed.