Effects of Inorganic Arsenic in Infant Rice Cereal on Children's
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Effects of Inorganic Arsenic in Infant Rice Cereal on Children’s Neurodevelopment December 7, 2017 Prepared for: Healthy Babies Bright Futures Submitted by: Andrea Chiger and Meghan T. Lynch Abt Associates 4550 Montgomery Avenue Suite 800 North Bethesda, MD 20814 CONTENTS Contents Contents .................................................................................................................................................. i Acronyms and Abbreviations ............................................................................................................. iii Executive Summary ............................................................................................................................. 1 Report Outline ...................................................................................................................................... 3 1. Background on Arsenic Sources and Health Effects ............................................................ 4 2. Standards for Inorganic Arsenic in Infant Rice Cereal ....................................................... 6 2.1 European Commission Standard ..................................................................................... 6 2.2 Proposed FDA Standard .................................................................................................. 7 3. Infant Rice Cereal Consumption, Arsenic Concentration, and Exposure Data ................ 8 3.1 Sources of Data on Arsenic Concentrations in Infant Food ............................................ 8 3.2 Sources of Data on Infant Rice Cereal Consumption .................................................... 11 3.2.1 What We Eat In America, NHANES ............................................................... 12 3.2.2 Nestlé Feeding Infants and Toddlers Study ...................................................... 12 3.2.3 Karagas et al. (2016) ......................................................................................... 13 3.3 Estimates of Daily Arsenic Exposures from Infant Rice Cereal ................................... 13 3.3.1 FDA Risk Assessment ...................................................................................... 13 3.3.2 Xue et al. (2010) ............................................................................................... 14 3.3.3 Karagas et al. (2016) ......................................................................................... 15 3.3.4 Carignan et al. (2016) ....................................................................................... 16 3.3.5 Shibata et al. (2016) .......................................................................................... 16 3.4 Comparison of Consumption and Exposure Estimate Data........................................... 17 3.5 Data Gaps and Limitations ............................................................................................ 19 4. Comparison of Exposures from Infant Rice Cereal to Health-Based Limits for Arsenic .................................................................................................................................... 22 4.1 Estimates of Arsenic Dose Associated with Various Scenarios of Infant Rice Cereal Consumption ................................................................................................................. 22 4.2 Health-Based Limits for Arsenic Exposures ................................................................. 25 4.2.1 U.S. EPA’s IRIS (1991) Reference Dose for Chronic Oral Exposures ............ 25 4.2.2 Tsuji et al.’s (2015) Reference Dose for the Neurodevelopmental Effects of Arsenic.............................................................................................................. 26 4.2.3 Agency for Toxic Substances and Disease Registry (2007) Minimal Risk Level ................................................................................................................. 27 Abt Associates Inorganic Arsenic and Neurodevelopment ▌pg. i CONTENTS 4.2.4 Shibata et al.’s (2016) Maximum Contaminant Level for Arsenic in Infant Rice Cereal ....................................................................................................... 28 4.3 Comparison of Health-Based Limits to Infant Rice Cereal Exposure Scenarios .......... 28 5. Review of the Literature on Arsenic Exposures and Decreased Intelligence ................... 31 5.1 Identification of Studies ................................................................................................. 31 5.2 Discussion of the Literature ........................................................................................... 36 6. Estimating IQ Losses in Children Based on Exposures to Arsenic .................................. 38 6.1 Selection of Concentration-Response Functions ........................................................... 39 6.1.1 Hamadani et al. (2011) ..................................................................................... 40 6.1.2 Wasserman et al. (2004) ................................................................................... 41 6.1.3 California Environmental Protection Agency (2008) and Massachusetts Department of Environmental Protection (2011) ............................................. 42 6.1.4 Wasserman et al. (2007) ................................................................................... 43 6.2 Estimates of Avoided IQ Loss Associated with Reductions in Arsenic Exposures from Infant Rice Cereal ................................................................................................. 44 6.2.1 Individual-Level Estimates ............................................................................... 45 6.2.2 Nationwide Estimates ....................................................................................... 48 6.3 Estimates of Avoided IQ Loss Associated with Reductions in Arsenic Exposures from Rice and Rice Products ......................................................................................... 50 6.4 Discussion of IQ Loss Methodologies and Estimates ................................................... 52 7. Conclusions ............................................................................................................................ 54 References ........................................................................................................................................... 56 Appendix A: Review of the Literature on the Health Effects of DMA Exposures ....................... 62 Appendix B: Additional Studies on the Association between Arsenic Exposures and IQ Loss .. 64 Abt Associates Inorganic Arsenic and Neurodevelopment ▌pg. ii ACRONYMS AND ABBREVIATIONS Acronyms and Abbreviations ANOVA Analysis of variance AsIII Arsenite AsV Arsenate ATSDR Agency for Toxic Substances and Disease Registry BMDL10 Benchmark dose lower confidence limit CalEPA California Environmental Protection Agency CONTAM Contaminants in the Food Chain DHHS U.S. Department of Health and Human Services DMA Dimethylarsinic acid EFSA European Food Safety Authority EPA U.S. Environmental Protection Agency FCID Food Consumption Intake Database FDA Food and Drug Administration FITS Feeding Infants and Toddlers Study HBBF Healthy Babies Bright Futures IARC International Agency for Research on Cancer IRIS Integrated Risk Information System kg bw Kilograms of body weight LOAEL Lowest observed adverse effect level LOD Limit of detection MassDEP Massachusetts Department of Environmental Protection MENTOR-3P Modeling Environment for Total Risk with Physiologically Based Pharmacokinetic Modeling for Populations MMA Monomethylarsonic acid MRL Minimal Risk Level NHANES National Health and Nutrition Evaluation Survey NHEXAS National Human Exposure Assessment Survey NOAEL No observed adverse effect level PBPK Physiologically based pharmacokinetic POD Point of departure ppb Parts per billion REL Reference Exposure Level RfD Reference dose SHEDS Stochastic Human Exposure and Dose Simulation STROBE Strengthening the Reporting of Observational Studies in Epidemiology TDS Total Diet Study TEL Threshold Effects Exposure Limit TMAO Trimethylarsine oxide USDA U.S. Department of Agriculture WPPSI Wechsler Preschool and Primary Scale of Intelligence WWEIA What We Eat in America Abt Associates Inorganic Arsenic and Neurodevelopment ▌pg. iii EXECUTIVE SUMMARY Executive Summary Healthy Babies Bright Futures (HBBF) asked Abt Associates to examine inorganic arsenic exposures associated with consumption of infant rice cereal, rice, and other rice products, and to evaluate the feasibility of quantitatively estimating IQ loss as a result of arsenic exposure from these rice products. This report summarizes the results of those efforts. Arsenic is a known toxicant that is commonly found in foods containing rice, such as infant rice cereal. Exposures to arsenic are associated with numerous adverse health effects, including cancer, cardiovascular disease, and adverse neurodevelopmental effects (Agency for Toxic Substances and Disease Registry [ATSDR], 2007). The Food and Drug Administration (FDA) recently proposed a standard of 100 ppb for arsenic in infant rice cereal based on a risk analysis and feasibility considerations. In support of this proposed standard, FDA conducted a risk assessment based on cancer endpoints, along with an exposure assessment. Additionally, FDA conducted a systematic literature review on inorganic arsenic exposures during pregnancy and through early childhood, and concluded that