Risk Assessment of Salmonellosis from Consumption of Alfalfa Sprouts and Evaluation of the Public Health Impact of Sprout Seed Treatment and Spent Irrigation Water Testing.

We developed a risk assessment of human salmonellosis associated with consumption of alfalfa sprouts in the United States to evaluate the public health impact of applying treatments to seeds (0-5-log10 reduction in Salmonella) and testing spent irrigation water (SIW) during production. The risk model considered variability and uncertainty in Salmonella contamination in seeds, Salmonella growth and spread during sprout production, sprout consumption, and Salmonella dose response. Based on an estimated prevalence of 2.35% for 6.8 kg seed batches and without interventions, the model predicted 76,600 (95% confidence interval (CI) 15,400-248,000) cases/year. Risk reduction (by 5- to 7-fold) predicted from a 1-log10 seed treatment alone was comparable to SIW testing alone, and each additional 1-log10 seed treatment was predicted to provide a greater risk reduction than SIW testing. A 3-log10 or a 5-log10 seed treatment reduced the predicted cases/year to 139 (95% CI 33-448) or 1.4 (95% CI <1-4.5), respectively. Combined with SIW testing, a 3-log10 or 5-log10 seed treatment reduced the cases/year to 45 (95% CI 10-146) or <1 (95% CI <1-1.5), respectively. If the SIW coverage was less complete (i.e., less representative), a smaller risk reduction was predicted, e.g., a combined 3-log10 seed treatment and SIW testing with 20% coverage resulted in an estimated 92 (95% CI 22-298) cases/year. Analysis of alternative scenarios using different assumptions for key model inputs showed that the predicted relative risk reductions are robust. This risk assessment provides a comprehensive approach for evaluating the public health impact of various interventions in a sprout production system.

Global assessment of select phytonutrient intakes by level of fruit and vegetable consumption.

Despite dietary recommendations that have repeatedly underscored the importance of increasing consumption of fruits and vegetables, intakes worldwide are lower than recommended levels. Consequently, the diets of many individuals may be lacking in nutrients and phytonutrients typical of a diet rich in a variety of fruits and vegetables. In the present study, we estimated phytonutrient intakes by adults categorised by sex, level of fruit and vegetable consumption (< 5 v. ≥ 5 servings/d), and geographic diet cluster. Intakes of nine select phytonutrients were estimated from the 2002-4 World Health Survey fruit and vegetable servings intake data (n 198,637), the FAO supply utilisation accounts data, and phytonutrient concentration data obtained from the US Department of Agriculture databases and the published literature. Percentage contributions to each phytonutrient intake from fruit and vegetable sources were also estimated. Estimated intakes of phytonutrients from fruits and vegetables varied across the thirteen geographic diet clusters, reflecting regional differences in both numbers and proportions of fruit and vegetable servings consumed, and the specific types of fruits and vegetables available in the diet. The mean phytonutrient intakes by adults consuming ≥ 5 servings/d of fruits and vegetables were approximately 2- to 6-fold the mean phytonutrient intakes by adults with low fruit and vegetable consumption (< 5 servings/d). In some cases, phytonutrient intakes by adults consuming ≥ 5 servings/d of fruits and vegetables in one geographic diet cluster were lower than the intakes by adults reporting < 5 servings/d in another cluster. The findings from this assessment provide important information regarding the major dietary patterns of phytonutrient intakes across geographic diet clusters.

Revising the daily values may affect food fortification and in turn nutrient intake adequacy.

The Nutrition Facts panel on food labels in the United States currently displays Daily Values (DVs) that are based on outdated RDAs. The FDA has indicated that it plans to update the DVs based on the newer Dietary Reference Intakes (DRIs), but there is controversy regarding the best method for calculating new DVs from the DRIs. To better understand the implications of DV revisions, assuming that manufacturers choose to maintain current label claims for micronutrients from voluntarily fortified foods, we modeled intake of 8 micronutrients using NHANES 2007-2008 data and 2 potential methods for calculating DVs: the population-weighted Estimated Average Requirement (EAR) and the population-coverage RDA. In each scenario, levels of fortified nutrients were adjusted to maintain the current %DV. Usual nutrient intakes and percentages with usual intakes less than the EAR were estimated for the U.S. population and subpopulations aged ≥ 4 y (n = 7976). For most nutrients, estimates of the percentage of the U.S. population with intakes below the EAR were similar regardless of whether the DV corresponded to the population-weighted EAR or the population-coverage RDA. Potential decreases were observed in adequacy of nutrients of concern for women of childbearing age, namely iron and folate (up to 9% and 3%, respectively), adequacy of calcium among children (up to 6%), and adequacy of vitamin A intakes in the total population (5%) assuming use of the population-weighted EAR compared with the population-coverage RDA for setting the DV. Results of this modeling exercise will help to inform decisions in revising the DVs.

Exposure to tobacco smoke based on urinary cotinine levels among Israeli smoking and nonsmoking adults: a cross-sectional analysis of the first Israeli human biomonitoring study.

BACKGROUND: Cotinine levels provide a valid measure of exposure to environmental tobacco smoke (ETS). The goal of this study was to examine exposure to tobacco smoke among smoking and nonsmoking Israeli adults and to identify differences in ETS exposure among nonsmokers by socio-demographic factors. METHODS: We analyzed urinary cotinine data from the first Israeli human biomonitoring study conducted in 2011. In-person questionnaires included data on socio-demographic and active smoking status. Cotinine levels were measured using a gas chromatography-mass spectrometry procedure. We calculated creatinine-adjusted urinary cotinine geometric means (GM) among smokers and nonsmokers, and by socio-demographic, smoking habits and dietary factors. We analyzed associations, in a univariable and multivariable analysis, between socio-demographic variables and proportions of urinary cotinine ≥1 µg/l (Limit of Quantification = LOQ) or ≥4 µg/l. RESULTS: Cotinine levels were significantly higher among 91 smokers (GM = 89.7 µg/g creatinine; 95% confidence interval [CI]: 47.4-169.6) than among 148 nonsmokers (GM = 1.3; 1.1-1.7). Among exclusive waterpipe smokers, cotinine levels were relatively high (GM = 53.4; 95% CI 12.3-232.7). ETS exposure was widespread as 62.2% of nonsmokers had levels ≥ LOQ, and was higher in males (75.8%) than in females (52.3%). In a multivariable model, urinary cotinine ≥ LOQ was higher in males (Prevalence ratio [PR] = 1.30; 95% CI: 1.02-1.64, p = 0.032) and in those with lower educational status (PR = 1.58; 1.04-2.38, p = 0.031) and decreased with age (PR = 0.99; 0.98-1.00, p = 0.020, per one additional year). There were no significant differences by ethnicity, residence type or country of birth. CONCLUSIONS: Our findings indicate widespread ETS exposure in the nonsmoking Israeli adult population, especially among males, and younger and less educated participants. These findings demonstrate the importance of human biomonitoring, were instrumental in expanding smoke-free legislation implemented in Israel on July 2012 and will serve as a baseline to measure the impact of the new legislation.

Desalination of water: nutritional considerations.

BACKGROUND: Desalination of seawater and brackish water (mixed seawater and freshwater) provides an increasing portion of the Israeli drinking water supply. However, desalinated water contains little calcium (Ca) and magnesium (Mg), and consumers may be at risk for deficiencies of these essential minerals. OBJECTIVES: To assess intakes of Mg and Ca from water, other beverages, and food in communities with different water supplies, and assess the proportion of individuals with intakes below the Estimated Average Requirement (EAR). METHODS: Telephone interviews were conducted using a food frequency questionnaire to assess Mg and Ca intakes by adults in four communities. The proportion of individuals with Mg and Ca intakes below the EAR were evaluated based on current intakes and on potential intakes assuming that desalinated water had been introduced countrywide. RESULTS: The proportion of individuals with Mg intake below the EAR was higher in Kibbutz Maagan Michael (30.6%), an agricultural settlement supplied with desalinated water, than in Hadera (16.7%), a city supplied by the National Water Carrier (NWC) (P < 0.05). The proportion of individuals with Ca intake below the EAR was higher in Maagan Michael (61.7%) than in the communities supplied with water from the NWC or mixed water (37.9%-48.2%), P < 0.05. CONCLUSIONS: Returning Mg and Ca to desalinated water may be beneficial for raising intakes in Israeli communities supplied with desalinated water. Individuals with intake of Mg and/or Ca below the EAR may be at risk for cardiac abnormalities and other medical conditions.

Cadmium physiologically based pharmacokinetic (PBPK) models for forward and reverse dosimetry: Review, evaluation, and adaptation to the U.S. population.

The goal of this study was to assess a cadmium (Cd) physiologically based pharmacokinetic (PBPK) model to evaluate Cd toxicological reference values (e.g. reference dose, tolerable intake, minimum risk level) adapted to the U.S. population. We reviewed and evaluated previously published Cd PBPK models and developed further adaptations to the 1978 Kjellström and Nordberg (KN) model. Specifically, we propose adaptations with updated U.S.-specific bodyweight, kidney weight and creatinine excretion models by using NHANES data as well as a stochastic PBPK model that provides credible intervals of uncertainty around mean populational estimates. We provide our model review and adaptations as well as present estimates from the newly adapted models using observed U.S. urinary Cd values as a function of gender and age and given dietary exposure as evaluated from NHANES/WWEIA and U.S. Total Diet Study data. Results show all newly adapted models provide acceptable mean estimates of urinary Cd in the U.S. The stochastic model provides credible intervals to further inform regulatory decision making. Validation of the estimated K-Cd concentration values was not possible as data for a representative population was not available. We developed a web-based tool implementing these models and other potential adaptations to facilitate PBPK model estimate comparisons.

Iodine in Foods and Dietary Supplements: A Collaborative Database Developed by NIH, FDA and USDA.

Data on the iodine content of foods and dietary supplements are needed to develop general population intake estimates and identify major contributors to intake. Samples of seafood, dairy products, eggs, baked products, salts, tap water, other foods and beverages, and dietary supplements were collected according to established sampling plans of the U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA). Samples were assayed for iodine content using inductively coupled plasma mass spectrometry with rigorous quality control measures. The food data were released through a collaboration of USDA, FDA, and the Office of Dietary Supplements-National Institutes of Health (ODS-NIH) as the USDA, FDA, and ODS-NIH Database for the Iodine Content of Common Foods at www.ars.usda.gov/mafcl. Iodine data for dietary supplements are available in the ODS-USDA Dietary Supplement Ingredient Database and the ODS Dietary Supplement Label Database. Data from the iodine databases linked to national dietary survey data can provide needed information to monitor iodine status and develop dietary guidance for the general U.S. population and vulnerable subgroups. This iodine information is critical for dietary guidance development, especially for those at risk for iodine deficiency (i.e., women of reproductive age and young children).

Implementing a risk-risk analysis framework to evaluate the impact of food intake shifts on risk of illness: a case study with infant cereal.

In food safety, process pathway risk assessments usually estimate the risk of illness from a single hazard and a single food and can inform food safety decisions and consumer advice. To evaluate the health impact of a potential change in diet, we need to understand not only the risk posed by the considered hazard and food but also the risk posed by the substitution food and other potential hazards. We developed a framework to provide decision-makers with a multi-faceted evaluation of the impact of dietary shifts on risk of illness. Our case study explored exposure to inorganic arsenic (iAs) and aflatoxins through consumption of infant cereals and the risk of developing lung, bladder and liver cancer over a lifetime. The estimated additional Disability-Adjusted Life Year (DALY) in the U.S. from exposure to iAs and aflatoxin based on available contamination and consumption patterns of infant rice and oat cereal is 4,921 (CI 90% 414; 9,071). If all infant cereal consumers shift intake (maintaining equivalent serving size and frequency) to only consuming infant rice cereal, the predicted DALY increases to 6,942 (CI 90% 326; 12,931). If all infant cereal consumers shift intake to only consuming infant oat cereal, the predicted DALY decreases to 1,513 (CI 90% 312; 3,356). Changes in contaminant concentrations or percent consumers, that could occur in the future, also significantly impact the predicted risk. Uncertainty in these risk predictions is primarily driven by the dose-response models. A risk-risk analysis framework provides decision-makers with a nuanced understanding of the public health impact of dietary changes and can be applied to other food safety and nutrition questions.

Toward a Better Understanding of Listeriosis Risk among Older Adults in the United States: Characterizing Dietary Patterns and the Sociodemographic and Economic Attributes of Consumers with These Patterns.

ABSTRACT: Older adults are at higher risk of invasive listeriosis compared with the general population. Some foods are more likely than others to be contaminated with or to contain high levels of Listeria monocytogenes. The objectives of this study were to (i) determine dietary consumption patterns among older adults in the United States; (ii) evaluate sociodemographic and economic characteristics of older adults associated with each pattern; (iii) determine intake of foods associated with larger relative risk of listeriosis within these patterns; and (iv) rank these patterns based on risk. Data related to older adults (age 60 and older) participating in the cross-sectional National Health and Nutrition Examination Surveys (NHANES) 2009 to 2010, 2011 to 2012, and 2013 to 2014 (n = 4,967) were included in these analyses. Cluster analysis was used to define dietary patterns based on 24-h dietary recalls from day 1 and day 2. Mean intake of foods associated with higher risk of listeriosis was examined within each pattern, and analysis of variance with Dunnett's method of adjustment was used to evaluate significant differences in mean intake of foods. Patterns were ranked based on relative risk of listeriosis, using outbreak illness attribution data. Five distinct dietary patterns were identified. Patterns ranked at highest relative risk of listeriosis, based on U.S. outbreak illness attribution data, were characterized by relatively higher intakes of fruits, vegetables, and cheeses (∼13% respondents) or cereal, milk, and yogurt (∼14% respondents). Individuals consuming these dietary patterns differed in sex, race, food security, self-rated diet quality, and self-rated health. Cluster analysis, despite methodological limitations, provides new information on consumption, sociodemographic, and economic characteristics of subgroups within susceptible populations, which may be used to target educational messages.

Lead exposures in older children (males and females 7-17 years), women of childbearing age (females 16-49 years) and adults (males and females 18+ years): FDA total diet study 2014-16.

Dietary exposures to lead were estimated for older children, females of childbearing age and adults based on lead concentration data from the FDA's Total Diet Study and on food consumption data from What We Eat In America (WWEIA), the food survey portion of the National Health and Nutrition Examination Survey (NHANES). Estimated mean exposures varied based on the population and on the three different substitution scenarios for lead values below the limit of detection (non-detects = 0; non-detects = limit of detection; hybrid approach). Estimated mean lead exposures range from 1.4 to 4.0 µg/day for older children (males and females 7-17 years), 1.6 to 4.6 µg/day for women of childbearing age (females 16-49 years) and 1.7 to 5.3 µg/day for adults (males and females 18 years and older). Estimated 90th percentile lead exposures range from 2.3 to 5.8 µg/day for older children, 2.8 to 6.7 µg/day for women of childbearing age and 3.2 to 7.8 µg/day for adults. Exposure estimates suggest some older children may be exposed to dietary lead above the FDA interim reference level for lead in children of 3 µg/day. The results of this study can be used by the FDA to prioritise research and regulatory efforts in the area of dietary lead exposure.

Children's exposures to lead and cadmium: FDA total diet study 2014-16.

Children are at potential risk for adverse effects from lead and cadmium exposures due to the effects of these elements on developing brains. Children's dietary exposures to lead and cadmium were estimated based on lead and cadmium concentration data from FDA's Total Diet Study (TDS) and on food consumption data from What We Eat In America (WWEIA), the food survey portion of the National Health and Nutrition Examination Study (NHANES). Estimated mean exposures vary based on age range (1-3 y, 4-6 y, or 1-6 y) and on substitution scenarios for values below the limit of detection (non-detects = 0; non-detects = limit of detection; hybrid approach). Estimated mean lead exposures range from 1 to 3.4 µg/day, with major contributions from grains, fruit, dairy, and mixtures (e.g. hamburgers, pizza, lasagna, soups). Estimated mean cadmium exposures range from 0.38 to 0.44 µg/kg bw/day, with major contributions from grains, mixtures, and vegetables. Estimated children's lead exposures declined slightly since 2004-08, but cadmium exposures did not decline. No safe level has been identified for lead exposures, and toxicologic reference values for cadmium range from 0.1 to 0.83 µg/kg bw/day. The data on lead and cadmium exposures, and on contributors to exposures, will inform research and regulatory priorities on mitigation of exposures to lead and cadmium.

Update on dietary intake of perchlorate and iodine from U.S. food and drug administration's total diet study: 2008-2012.

The U.S. Food and Drug Administration's (FDA) Total Diet Study (TDS) monitors the US food supply for pesticide residues, industrial chemicals, radionuclides, nutrients, and toxic elements. Perchlorate and iodine intakes based on concentrations in TDS samples collected between 2008 and 2012 were estimated in order to update an earlier TDS dietary assessment. Perchlorate is used as an oxidizing agent in rocket and missile fuel, is formed naturally in the atmosphere, and occurs naturally in some soils. Because of perchlorate's presence in soil, and in irrigation, processing, and source water, it is widely found in food. Iodine was included in the study because perchlorate at high doses interferes with iodide uptake in the thyroid. Iodine (the elemental form of iodide) is essential for growth and development, and metabolism. This study uses a novel statistical method based on a clustered zero-inflated lognormal distribution model to estimate mean and 95th percentile confidence interval concentrations for perchlorate and iodine in US foods. These estimates were used to estimate mean perchlorate and iodine exposures for the total US population and for 14 age/sex groups in the US population. Estimated mean perchlorate intake for the total US population was 0.13 µg/kg bw/day, with mean intakes for the 14 age/sex groups between 0.09 and 0.43 µg/kg bw/day. The estimated mean intakes of perchlorate for all age/sex groups were below EPA's reference dose (RfD) of 0.7 µg/kg bw/day. The estimated mean iodine intake for the total US population was 216.4 µg/person/day, with mean intakes ranging from 140.9 to 296.3 µg/person/day for the 14 age/sex groups, with all age/sex groups exceeding their respective estimated average requirements (EARs).

Estimated US infant exposures to 3-MCPD esters and glycidyl esters from consumption of infant formula.

A dietary exposure assessment was conducted for 3-monochloropropane-1,2-diol (3-MCPD) esters (3-MCPDE) and glycidyl esters (GE) in infant formulas available for consumption in the United States. 3-MCPDE and GE are food contaminants generated during the deodorisation of refined edible oils, which are used in infant formulas and other foods. 3-MCPDE and GE are of potential toxicological concern because these compounds are metabolised to free 3-MCPD and free glycidol in rodents and may have the same metabolic fate in humans. Free 3-MCPD and free glycidol have been found to cause adverse effects in rodents. Dietary exposures to 3-MCPDE and GE from consumption of infant formulas are of particular interest because formulas are the sole or primary food source for some infants. In this analysis, US Food and Drug Administration data on 3-MCPDE and GE concentrations (as 3-MCPD and glycidol equivalents, respectively) in a small convenience sample of infant formulas were used to estimate exposures from consumption of formula by infants 0-6 months of age. 3-MCPDE and GE exposures based on mean concentrations in all formulas were estimated at 7-10 and 2 µg/kg bw/day, respectively. Estimated mean exposures from consumption of formulas produced by individual manufacturers ranged from 1 to 14 µg/kg bw/day for 3-MCPDE and from 1 to 3 µg/kg for GE.

A Quantitative Risk Assessment of Human Salmonellosis from Consumption of Pistachios in the United States.

We developed a quantitative risk assessment model to assess the risk of human nontyphoidal salmonellosis from consumption of pistachios in the United States and to evaluate the impact of Salmonella treatments (1- to 5-log reductions). The exposure model estimating prevalence and contamination levels of Salmonella at consumption included steps in pistachio processing such as transport from grower to huller, removal of the hull through wet abrasion, separation of pistachio floaters (immature, smaller nuts) and sinkers (mature, larger nuts) in a flotation tank, drying, storage, and partitioning. The risks of illness per serving and per year were evaluated by including a Salmonella dose-response model and U.S. consumption data. The spread of Salmonella through float tank water, delay in drying resulting in growth, increased Salmonella levels through pest infestation during storage (pre- and posttreatment), and a simulation of the 2016 U.S. salmonellosis outbreak linked to consumption of pistachios were the modeled atypical situations. The baseline model predicted one case of salmonellosis per 2 million servings (95% CI: one case per 5 million to 800,000 servings) for sinker pistachios and one case per 200,000 servings (95% CI: one case per 400,000 to 40,000 servings) for floater pistachios when no Salmonella treatment was applied and pistachios were consumed as a core product (>80% pistachio) uncooked at home. Assuming 90% of the pistachio supply is sinkers and 10% is floaters, the model estimated 419 salmonellosis cases per year (95% CI: 200 to 1,083 cases) when no Salmonella treatment was applied. A mean risk of illness of less than one case per year was estimated when a minimum 4-log reduction treatment was applied to the U.S. pistachio supply, similar to the results of the Salmonella risk assessment for almonds. This analysis revealed that the predicted risk of illness per serving is higher for all atypical situations modeled compared with the baseline, and delay in drying had the greatest impact on consumer risk.

A Quantitative Assessment of the Risk of Human Salmonellosis Arising from the Consumption of Almonds in the United States: The Impact of Preventive Treatment Levels.

The presence of Salmonella on almonds continues to result in product-related outbreaks and recalls in the United States. In this study, the impact of microbial reduction treatment levels (1 to 5 log CFU) on the risk of human salmonellosis from the consumption of almond kernels in the United States was evaluated. An exposure model, including major steps in almond processing, was used to estimate prevalence and levels of contamination of Salmonella on almonds at the point of consumption. A Salmonella dose-response model and consumption data for almonds in the United States were used to assess risk of illness per serving and per year, quantifying variability and uncertainty separately. A 3-log reduction treatment resulted in a predicted mean risk of illness of two cases per year for almonds consumed as a core product not cooked at home (95% confidence interval [CI], one to four cases), one case per year for almonds consumed as an ingredient not cooked at home (95% CI, one to two cases), and less than one case per year for almonds consumed as an ingredient cooked at home (95% CI, 7 × 10-7 to 3 × 10-6 cases). A minimum 4-log reduction treatment resulted in an estimated mean risk of illness below one case per year in the United States. This study also includes an assessment of the risk of human salmonellosis as a result of an exceptional situation, which results in higher risk estimates compared with the baseline model. The exceptional situations modeled posttreatment resulted in estimates of mean risk that were not significantly affected by treatment level. Sensitivity analysis results showed initial Salmonella contamination level to be the factor with the most impact on risk per serving estimates, given a certain treatment level. The risk assessment also includes a simulation of the events that occurred in 2001. Treatment levels with a minimum 4-log microbial reduction would have been sufficient to prevent the outbreak cases. The uncertainty range in the estimates indicates that additional information is needed to make more precise predictions of this specific outbreak event.

A Quantitative Assessment of the Risk of Human Salmonellosis Arising from the Consumption of Pecans in the United States.

A quantitative risk assessment was conducted to assess the risk of human salmonellosis acquired from consumption of pecans in the United States. The model considered the potential for Salmonella survival, growth, and recontamination of pecans from the sheller to the consumer, including steps such as immersion in water, drying, conditioning, cracking, partitioning, and storage. Five theoretical microbial reduction treatment levels (1 to 5 log CFU) were modeled. Data from the 2010 to 2013 surveys by the National Pecan Shellers Association were used for initial prevalence and contamination levels. The impacts of atypical situations in the pecan production system were also evaluated. Higher initial contamination levels, recontamination during processing, and a delay in drying postconditioning were the modeled atypical situations. The baseline model predicted a mean risk of salmonellosis in the United States from consumption of in-shell and shelled pecans processed by cold conditioning with no microbial reduction treatment and no further home cooking as 1 case per 775,193 servings (95% confidence interval [CI]: 1 case per 1,915,709 to 178,253 servings). This predicted risk per serving was estimated as a mean of 529 cases of salmonellosis per year (95% CI: 213 to 2,295 cases). Hot conditioning for shelled pecans and microbial reduction treatment of both shelled and in-shell pecans had a significant impact on the predicted mean risk of illness. Assuming 77% of the shelled pecans sold at retail (i.e., 80% of the retail supply) received hot conditioning, the mean estimated salmonellosis cases per year from consumption of in-shell and shelled pecans uncooked at home was 203 (95% CI: 81 to 882 cases) if no additional microbial reduction treatment were applied. The predicted risk of illness per serving was higher for all atypical situations modeled compared with the baseline model, and delay in drying had the greatest impact on risk.

Iodine in food- and dietary supplement-composition databases.

The US Food and Drug Administration (FDA) and the Nutrient Data Laboratory (NDL) of the USDA Agricultural Research Service have worked independently on determining the iodine content of foods and dietary supplements and are now harmonizing their efforts. The objective of the current article is to describe the harmonization plan and the results of initial iodine analyses accomplished under that plan. For many years, the FDA's Total Diet Study (TDS) has measured iodine concentrations in selected foods collected in 4 regions of the country each year. For more than a decade, the NDL has collected and analyzed foods as part of the National Food and Nutrient Analysis Program; iodine analysis is now being added to the program. The NDL recently qualified a commercial laboratory to conduct iodine analysis of foods by an inductively coupled plasma mass spectrometry (ICP-MS) method. Co-analysis of a set of samples by the commercial laboratory using the ICP-MS method and by the FDA laboratory using its standard colorimetric method yielded comparable results. The FDA recently reviewed historical TDS data for trends in the iodine content of selected foods, and the NDL analyzed samples of a limited subset of those foods for iodine. The FDA and the NDL are working to combine their data on iodine in foods and to produce an online database that can be used for estimating iodine intake from foods in the US population. In addition, the NDL continues to analyze dietary supplements for iodine and, in collaboration with the NIH Office of Dietary Supplements, to publish the data online in the Dietary Supplement Ingredient Database. The goal is to provide, through these 2 harmonized databases and the continuing TDS focus on iodine, improved tools for estimating iodine intake in population studies.

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

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 ≤8 y, the prevalence of excessive iodine intake was high by either method. CONCLUSIONS: The consideration of dietary iodine intake from all sources may provide a more complete understanding of population prevalences of iodine inadequacy and excess and thus better inform dietary guidance than consideration of UIC alone. Methods of adjusting UIC for within-person variation are needed to improve the accuracy of prevalence assessments based on UIC.