Scientific Publications by FDA Staff

Am J Clin Nutr 2016 Sep;104 Suppl 3:888-97S

Comparison of 2 methods for estimating the prevalences of inadequate and excessive iodine intakes.

Juan W, Trumbo PR, Spungen JH, Dwyer JT, Carriquiry AL, Zimmerman TP, Swanson CA, Murphy SP

BACKGROUND: Prevalences of iodine inadequacy and excess are usually evaluated by comparing the population distribution of urinary iodine concentration (UIC) in spot samples with established UIC cutoffs. To our knowledge, until now, dietary intake data have not been assessed for this purpose. OBJECTIVE: Our objective was to compare 2 methods for evaluating the prevalence of iodine inadequacy and excess in sex- and life stage-specific subgroups of the US population: one that uses UIC cutoffs, and one that uses iodine intake cutoffs. DESIGN: By using the iodine concentrations of foods measured in the US Food and Drug Administration's Total Diet Study (TDS), dietary intake data from the NHANES 2003-2010, and a file that maps each NHANES food to a TDS food with similar ingredients, we estimated each NHANES participant's iodine intake from each NHANES food as the mean iodine concentration of the corresponding TDS food in samples gathered over the same 2-y period. We calculated prevalences of iodine inadequacy and excess in each sex- and life stage-specific subgroup by both the UIC cutoff method and the iodine intake cutoff method-using the UIC values and dietary intakes reported for NHANES participants who provided both types of data-and compared the prevalences across methods. RESULTS: We found lower prevalences of iodine inadequacy across all sex- and life stage-specific subgroups with the iodine intake cutoff method than with the UIC cutoff method; for pregnant females, the respective prevalences were 5.0% and 37.9%. For children aged