ABSTRACT
Background: There is limited information on relationships among biomarkers of thiamine status (whole blood thiamine diphosphate [ThDP], erythrocyte transketolase activity coefficient [ETKac], and human milk thiamine [MTh]) and clinical manifestations of thiamine deficiency. Objectives: This study aimed to explore correlations among these biomarkers and thiamine responsive disorders (TRDs), a diagnosis based on favorable clinical response to thiamine. Methods: Hospitalized infants and young children (aged 21 d to <18 mo) with respiratory, cardiac, and/or neurological symptoms suggestive of thiamine deficiency were treated with parenteral thiamine (100 mg daily) for ≥3 d alongside other treatments and re-examined systematically. Clinical case reports were reviewed by 3 pediatricians, who determined TRD or non-TRD status. Children in a community comparison group were matched by age, sex, and residence. Venous whole blood ThDP and MTh were determined by high-performance liquid chromatography fluorescence detection and ETKac in washed erythrocytes by ultraviolet spectrophotometry. Associations between biomarkers were assessed using Spearman correlations, and biomarker cutoffs predictive of TRD and ETKac >1.25 were explored using area under the receiver operating characteristic curve framework. Results: Thiamine biomarkers were available for 287 hospitalized children and 228 community children (mean age 4.7 mo; 59.4% male). Median (interquartile range [IQR]) ThDP and ETKac were 66.9 nmol/L (IQR: 41.4, 96.9 nmol/L) and 1.25 nmol/L (IQR: 1.11, 1.48 nmol/L), respectively, among hospitalized children, and 64.1 nmol/L (IQR: 50.0, 85.3 nmol/L) and 1.22 nmol/L (IQR: 1.12, 1.37 nmol/L) among 228 community children (P > 0.05 for both). Forty-five percent of breastfeeding mothers of infants <6 mo had MTh <90 µg/L. ThDP and ETKac, but not MTh, were significantly different between 152 children with TRD and 122 without TRD, but overlapping distributions undermined prediction of individual responses to thiamine. Conclusions: Although ETKac, ThDP, and MTh are useful biomarkers of population thiamine status, none of the biomarkers reliably identified individual children with TRD. ThDP is more practical for population assessment because preparing washed erythrocytes is not required.This trial was registered at clinicaltrials.gov as NCT03626337.
ABSTRACT
Large-scale food fortification (LSFF) can increase dietary micronutrient intake and improve micronutrient status. Here we used food balance sheet data from the Food and Agriculture Organization of the United Nations to estimate current country-specific prevalences of inadequate zinc intake. We assessed the potential effects of improving existing LSFF programmes for cereal grains or implementing new programmes in 40 countries where zinc deficiency is a potential public health problem. Accounting for LSFF programmes as currently implemented, 15% of the global population (1.13 billion individuals) is estimated to have inadequate zinc intake. In countries where zinc deficiency is a potential public health problem, the implementation of high-quality mandatory LSFF programmes that include zinc as a fortificant would substantially increase the availability of zinc in the national food supply, reducing the estimated prevalence of inadequate zinc intake by up to 50% globally. Investments in strong LSFF programmes could have a substantial impact on population zinc status.
Subject(s)
Food, Fortified , Zinc , Humans , Zinc/deficiency , Zinc/administration & dosage , Prevalence , Global Health , Edible Grain , Nutritional Status , Mandatory ProgramsABSTRACT
Bioplastics are considered sustainable alternatives to conventional microplastics which are recognized as a threat to terrestrial ecosystems. However, little is known about the potential ecotoxicological effects of bioplastics on soil fauna and ecosystems. The present study assessed the toxicity of microplastics [Polystyrene (PS), Polyethylene (PE)] and bioplastics [Polyvinyl alcohol (PVA), Sodium polyacrylate (NaPa) on a key soil fauna Oppia nitens, a soil oribatid mite, and investigated the ecological relevance of O. nitens avoidance response as a valuable tool for the risk assessment of contaminated soils such as the Superfund sites. Findings showed that the mites' net response indicated avoidance behavior such that in most cases as concentrations of micro- and bioplastics increased, so did the avoidance responses. The avoidance EC50 endpoints showed PS < PE < PVA < NaPa, indicating higher deleterious effects of microplastics. High toxicity of PS in soils to O. nitens at EC50 of 165 (±25) mg/kg compared to bioplastics and other known contaminants poses an enormous threat to soil. For bioplastics in this study, there were no significant avoidances at concentrations up to 16,200 mg/kg compared to PS and PE which showed avoidance responses at 300 and 9000 mg/kg respectively, implying that bioplastics might be relatively safer to soil mites compared to conventional microplastics. Also, results indicated that long-term heavy metal pollution such as in contaminated Superfund sites decreased microbial biomass; a useful bioindicator of soil pollution. Furthermore, O. nitens avoidance of heavy metals contaminated sites demonstrated the ecological relevance of avoidance response test when assessing the habitat integrity of contaminated soil. The present study further supports the inclusion of the oribatid mite, O. nitens in the ecological risk assessment of contaminants in soil.
Subject(s)
Microplastics , Mites , Soil Pollutants , Animals , Microplastics/toxicity , Soil Pollutants/toxicity , Mites/drug effects , Ecotoxicology , Soil/chemistry , Environmental Monitoring/methods , Polyethylene/toxicity , Ecosystem , Risk Assessment , Plastics/toxicity , Avoidance Learning/drug effectsABSTRACT
Simulating the quantum dynamics of molecules in the condensed phase represents a longstanding challenge in chemistry. Trapped-ion quantum systems may serve as a platform for the analog-quantum simulation of chemical dynamics that is beyond the reach of current classical-digital simulation. To identify a 'quantum advantage' for these simulations, performance analysis of both analog-quantum simulation on noisy hardware and classical-digital algorithms is needed. In this Review, we make a comparison between a noisy analog trapped-ion simulator and a few choice classical-digital methods on simulating the dynamics of a model molecular Hamiltonian with linear vibronic coupling. We describe several simple Hamiltonians that are commonly used to model molecular systems, which can be simulated with existing or emerging trapped-ion hardware. These Hamiltonians may serve as stepping stones towards the use of trapped-ion simulators for systems beyond the reach of classical-digital methods. Finally, we identify dynamical regimes in which classical-digital simulations seem to have the weakest performance with respect to analog-quantum simulations. These regimes may provide the lowest hanging fruit to make the most of potential quantum advantages.
ABSTRACT
Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.
Subject(s)
Anemia, Iron-Deficiency , Anemia , Thiamine Deficiency , Adult , Female , Humans , Male , Pregnancy , Young Adult , Anemia/epidemiology , Anemia, Iron-Deficiency/epidemiology , Ferritins , Hemoglobins/metabolism , Laos/epidemiology , Prevalence , Risk Factors , Thiamine Deficiency/epidemiologyABSTRACT
We aim to provide a practical approach to assess anemia and its primary causes, both in clinical settings and in the context of public health programs. Anemia remains a global challenge; thus, to achieve goals for anemia reduction and assess progress, standardized approaches are required for the assessment of anemia and its causes. We first provide a brief review of how to assess anemia, based on hemoglobin concentrations and cutoffs that correspond to age, sex, and physiologic status. Next, we discuss how to assess the likely causes of anemia in different settings. The causes of anemia are classified as non-nutritional (for example, because of infection, inflammation, blood loss, or genetic disorders) or nutrition-specific (for example, because of deficiencies of iron, vitamin A, riboflavin, vitamin B12, or folate). There is an important overlap between these 2 categories, such as the increased likelihood of iron deficiency in the context of inflammation. Given the multifaceted nature of anemia etiology, we introduce a framework for anemia assessment based on the "ecology of anemia," which recognizes its many overlapping causes. This conceptual framework is meant to inform what data on anemia causes may need to be collected in population surveys. The framework has a supporting table with information on the diagnostic tests, biomarkers and proposed cutoffs, characteristics, and feasibility of collecting the myriad information that can help elucidate the anemia etiology. We also provide examples of how this framework can be applied to interpret the anemia risk factor data from population-based surveys that can inform decisions about context-specific interventions. Finally, we present research gaps and priorities related to anemia assessment.
Subject(s)
Anemia, Iron-Deficiency , Anemia , Iron Deficiencies , Humans , Public Health , Anemia/diagnosis , Anemia/epidemiology , Anemia/etiology , Iron , Inflammation/complications , Anemia, Iron-Deficiency/diagnosis , Anemia, Iron-Deficiency/epidemiologyABSTRACT
Sustainable Development Goal 2.2-to end malnutrition by 2030-includes the elimination of child wasting, defined as a weight-for-length z-score that is more than two standard deviations below the median of the World Health Organization standards for child growth1. Prevailing methods to measure wasting rely on cross-sectional surveys that cannot measure onset, recovery and persistence-key features that inform preventive interventions and estimates of disease burden. Here we analyse 21 longitudinal cohorts and show that wasting is a highly dynamic process of onset and recovery, with incidence peaking between birth and 3 months. Many more children experience an episode of wasting at some point during their first 24 months than prevalent cases at a single point in time suggest. For example, at the age of 24 months, 5.6% of children were wasted, but by the same age (24 months), 29.2% of children had experienced at least one wasting episode and 10.0% had experienced two or more episodes. Children who were wasted before the age of 6 months had a faster recovery and shorter episodes than did children who were wasted at older ages; however, early wasting increased the risk of later growth faltering, including concurrent wasting and stunting (low length-for-age z-score), and thus increased the risk of mortality. In diverse populations with high seasonal rainfall, the population average weight-for-length z-score varied substantially (more than 0.5 z in some cohorts), with the lowest mean z-scores occurring during the rainiest months; this indicates that seasonally targeted interventions could be considered. Our results show the importance of establishing interventions to prevent wasting from birth to the age of 6 months, probably through improved maternal nutrition, to complement current programmes that focus on children aged 6-59 months.
Subject(s)
Cachexia , Developing Countries , Growth Disorders , Malnutrition , Child, Preschool , Humans , Infant , Infant, Newborn , Cachexia/epidemiology , Cachexia/mortality , Cachexia/prevention & control , Cross-Sectional Studies , Growth Disorders/epidemiology , Growth Disorders/mortality , Growth Disorders/prevention & control , Incidence , Longitudinal Studies , Malnutrition/epidemiology , Malnutrition/mortality , Malnutrition/prevention & control , Rain , SeasonsABSTRACT
Globally, 149 million children under 5 years of age are estimated to be stunted (length more than 2 standard deviations below international growth standards)1,2. Stunting, a form of linear growth faltering, increases the risk of illness, impaired cognitive development and mortality. Global stunting estimates rely on cross-sectional surveys, which cannot provide direct information about the timing of onset or persistence of growth faltering-a key consideration for defining critical windows to deliver preventive interventions. Here we completed a pooled analysis of longitudinal studies in low- and middle-income countries (n = 32 cohorts, 52,640 children, ages 0-24 months), allowing us to identify the typical age of onset of linear growth faltering and to investigate recurrent faltering in early life. The highest incidence of stunting onset occurred from birth to the age of 3 months, with substantially higher stunting at birth in South Asia. From 0 to 15 months, stunting reversal was rare; children who reversed their stunting status frequently relapsed, and relapse rates were substantially higher among children born stunted. Early onset and low reversal rates suggest that improving children's linear growth will require life course interventions for women of childbearing age and a greater emphasis on interventions for children under 6 months of age.
Subject(s)
Developing Countries , Growth Disorders , Adult , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Asia, Southern/epidemiology , Cognition , Cross-Sectional Studies , Developing Countries/statistics & numerical data , Developmental Disabilities/epidemiology , Developmental Disabilities/mortality , Developmental Disabilities/prevention & control , Growth Disorders/epidemiology , Growth Disorders/mortality , Growth Disorders/prevention & control , Longitudinal Studies , MothersABSTRACT
Growth faltering in children (low length for age or low weight for length) during the first 1,000 days of life (from conception to 2 years of age) influences short-term and long-term health and survival1,2. Interventions such as nutritional supplementation during pregnancy and the postnatal period could help prevent growth faltering, but programmatic action has been insufficient to eliminate the high burden of stunting and wasting in low- and middle-income countries. Identification of age windows and population subgroups on which to focus will benefit future preventive efforts. Here we use a population intervention effects analysis of 33 longitudinal cohorts (83,671 children, 662,763 measurements) and 30 separate exposures to show that improving maternal anthropometry and child condition at birth accounted for population increases in length-for-age z-scores of up to 0.40 and weight-for-length z-scores of up to 0.15 by 24 months of age. Boys had consistently higher risk of all forms of growth faltering than girls. Early postnatal growth faltering predisposed children to subsequent and persistent growth faltering. Children with multiple growth deficits exhibited higher mortality rates from birth to 2 years of age than children without growth deficits (hazard ratios 1.9 to 8.7). The importance of prenatal causes and severe consequences for children who experienced early growth faltering support a focus on pre-conception and pregnancy as a key opportunity for new preventive interventions.
Subject(s)
Cachexia , Developing Countries , Growth Disorders , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Pregnancy , Cachexia/economics , Cachexia/epidemiology , Cachexia/etiology , Cachexia/prevention & control , Cohort Studies , Developing Countries/economics , Developing Countries/statistics & numerical data , Dietary Supplements , Growth Disorders/epidemiology , Growth Disorders/prevention & control , Longitudinal Studies , Mothers , Sex Factors , Malnutrition/economics , Malnutrition/epidemiology , Malnutrition/etiology , Malnutrition/prevention & control , AnthropometryABSTRACT
Micronutrient deficiencies result in a broad range of adverse health and functional consequences, but the true prevalence of specific deficiencies remains uncertain because limited information is available from nationally representative surveys using recommended biomarkers. The present review compares various reported national deficiency prevalence estimates for nutrients and years where the estimates overlap for individual countries that conducted nationally representative surveys and explores possible reasons for any discrepancies discovered. Nationally representative micronutrient status surveys that were conducted since 2000 among preschool-aged children or women of reproductive age and included assessment of iron, vitamin A, or zinc status based on recognized biomarkers were considered eligible for inclusion, along with any modeled deficiency prevalence estimates for these same countries and years. There was considerable variation across different published prevalence estimates, with larger inconsistencies when the prevalence estimate was based on proxies, such as hemoglobin for iron deficiency and dietary zinc availability for zinc deficiency. Numerous additional methodological issues affected the prevalence estimates, such as which biomarker and what cutoff was used to define deficiency, whether the biomarker was adjusted for inflammation, and what adjustment method was used. For some country-years, the various approaches resulted in fairly consistent prevalence estimates. For other country-years, however, the results differed markedly and changed the conclusions regarding the existence and severity of the micronutrient deficiency as a public health concern. In conclusion, to determine micronutrient status, we consider the assessment of one of the recommended biomarkers in a population representative survey as the best available information. If indicated, results should be adjusted for inflammation and generally acceptable cutoffs should be applied to facilitate comparisons, although individual countries may also apply nationally defined cutoffs to determine when and where to intervene. Global consensus is needed on best practices for presenting survey results and defining the prevalence of deficiency.
Subject(s)
Anemia, Iron-Deficiency , Folic Acid Deficiency , Malnutrition , Trace Elements , Vitamin A Deficiency , Child , Child, Preschool , Female , Humans , Iron , Vitamin A , Anemia, Iron-Deficiency/epidemiology , Prevalence , Vitamin A Deficiency/epidemiology , Vitamin A Deficiency/complications , Folic Acid Deficiency/complications , Folic Acid Deficiency/epidemiology , Malnutrition/epidemiology , Minerals , Zinc , Micronutrients , Inflammation/complications , BiomarkersABSTRACT
Conical intersections often control the reaction products of photochemical processes and occur when two electronic potential energy surfaces intersect. Theory predicts that the conical intersection will result in a geometric phase for a wavepacket on the ground potential energy surface, and although conical intersections have been observed experimentally, the geometric phase has not been directly observed in a molecular system. Here we use a trapped atomic ion system to perform a quantum simulation of a conical intersection. The ion's internal state serves as the electronic state, and the motion of the atomic nuclei is encoded into the motion of the ions. The simulated electronic potential is constructed by applying state-dependent optical forces to the ion. We experimentally observe a clear manifestation of the geometric phase using adiabatic state preparation followed by motional state measurement. Our experiment shows the advantage of combining spin and motion degrees for quantum simulation of chemical reactions.
ABSTRACT
In this review, the designs and recent developments of polymer-based drug delivery of Poly(lactic-co-glycolic acid) (PLGA) will be discussed for the possible treatment of age-related macular degeneration (AMD). PLGA is a versatile co-polymer that consists of synthetic lactic acid and glycolic acid monomers that are constructed to produce nanoparticles, microparticles, and scaffolds for the intraocular delivery of various drugs. As an FDA-approved polymer, PLGA has historically been well-suited for systemic slow-sustained release therapies due to its performance in biodegradability and biocompatibility. This review will examine recent in vitro and in vivo studies that provide evidence for PLGA-based particles as a therapeutic drug carrier for the treatment of AMD. Anti-angiogenic and antiproliferative effects of small peptides, small molecules, RNA molecules, and proteins within PLGA particles are briefly discussed. AMD is a leading cause of central vision loss in people over 55 years and the number of those afflicted will rise as the aging population increases. AMD has two forms that are often sequential. Dry AMD and wet AMD account for 85-90% and 10-15% of cases, respectively. The distinct categories of PLGA-based drug delivery vehicles are important for dispensing novel small molecules, RNA molecules, peptides, and proteins as a long-term effective treatment of AMD.
Subject(s)
Retina , Wet Macular Degeneration , Humans , Aged , Drug Delivery Systems , Drug Carriers , Wet Macular Degeneration/drug therapy , RNAABSTRACT
As a result of the Jerome Avenue Corridor re-zoning in Bronx, New York, the Jerome Avenue Public Health Task-force was convened by local elected officials in December 2018. Facilitated by the New York City Department of Health and Mental Hygiene, the taskforce consists of a core group of 15 committed organizations from local civic, government, healthcare, and social service agencies, as well as neighborhood residents. Striving to address common challenges faced by diverse partners, the taskforce implemented intentional strategies to enable transparent communication and tackle power dynamics. Best practices and lessons learned from this high-functioning coalition can serve as a model for future multi-sector collective action dedicated to health and community planning.
Subject(s)
Community-Based Participatory Research , Public Health , Humans , Communication , Residence Characteristics , New York CityABSTRACT
Dietary intake and biomarkers of micronutrient status of 100 non-pregnant women of reproductive age (NPWRA) were assessed to determine optimal levels of iron, zinc, vitamin B12, and folic acid to include in multiply-fortified salt (MFS) that will be evaluated in an upcoming trial. Weighed food records were obtained from participants to measure intake of micronutrients and discretionary salt, and to assess adequacy using Indian Nutrient Reference Values (NRVs). Statistical modeling was used to determine optimal fortification levels to reduce inadequate micronutrient intake while limiting intake above the upper limit. Fasting blood samples were obtained to assess iron, zinc, vitamin B12, and folate status. In usual diets, inadequate intake of iron (46%), zinc (95%), vitamin B12 (83%), and folate (36%) was high. Mean intake of discretionary salt was 4.7 g/day. Prevalence estimates of anemia (37%), iron deficiency (67%), zinc deficiency (34%), vitamin B12 insufficiency (37%), and folate insufficiency (70%) were also high. Simulating the addition of optimized MFS to usual diets resulted in percentage point (pp) reductions in inadequate intake by 29 pp for iron, 76 pp for zinc, 81 pp for vitamin B12, and 36 pp for folate. MFS holds potential to reduce the burden of micronutrient deficiencies in this setting.
Subject(s)
Folic Acid Deficiency , Malnutrition , Humans , Female , Iron , Vitamin B 12 , Zinc , Prevalence , Folic Acid , Malnutrition/epidemiology , Folic Acid Deficiency/epidemiology , Micronutrients , Sodium Chloride, Dietary , Sodium Chloride , Food, FortifiedABSTRACT
Electron transfer within and between molecules is crucial in chemistry, biochemistry, and energy science. This study describes a quantum simulation method that explores the influence of light polarization on electron transfer between two molecules. By implementing precise and coherent control among the quantum states of trapped atomic ions, we can induce quantum dynamics that mimic the electron-transfer dynamics in molecules. We use three-level systems (qutrits), rather than traditional two-level systems (qubits), to enhance the simulation efficiency and realize high-fidelity simulations of electron-transfer dynamics. We treat the quantum interference between the electron coupling pathways from a donor with two degenerate excited states to an acceptor and analyze the transfer efficiency. We also examine the potential error sources that enter the quantum simulations. The trapped-ion systems have favorable scalings with system size compared to those of classical computers, promising access to richer electron-transfer simulations.
ABSTRACT
Background: The Lives Saved Tool (LiST) is a mathematical modelling tool for estimating the survival, health, and nutritional impacts of scaling intervention coverage in low- and middle-income countries (LMICs). Various nutrition interventions are included in LiST and are regularly (and independently) reviewed and updated as new data emerge. This manuscript describes our latest in-depth review of nutrition evidence, focusing on intervention efficacy, appropriate population-affected fractions, and new interventions for potential inclusion in the LiST model. Methods: An external advisory group (EAG) was assembled to review evidence from systematic reviews on intervention-outcome (I-O) pairs for women and children under five years of age. GRADE quality was assigned to each pair based on a LiST-specific checklist to facilitate consistent decisions during the consideration. For existing interventions with new information, the EAG was asked to recommend whether to update the default efficacy values and population-affected fractions. For the new interventions, the EAG decided whether there was sufficient evidence of benefit, and in affirmative cases, information on the efficacy and affected fraction values that could be used. Decisions were based on expert group consensus. Results: Overall, the group reviewed 53 nutrition-related I-O pairs, including 25 existing and 28 new ones. Efficacy and population-affected fractions were updated for seven I-O pairs; three pairs were updated for efficacy estimates only, three were updated for population-affected fractions only; and nine new I-O pairs were added to the model, bringing the total of nutrition-related I-O pairs to 34. Included in the new I-O pairs were two new nutrition interventions added to LIST: zinc fortification and neonatal vitamin A supplementation. Conclusions: For modelling tools like LiST to be useful, it is crucial to update interventions, efficacy and population-affected fractions as new evidence becomes available. The present updates will enable LiST users to better estimate the potential health, nutrition, and survival benefits of investing in nutrition.
Subject(s)
Family , Models, Theoretical , Child , Child, Preschool , Female , Humans , Infant, Newborn , Nutritional StatusABSTRACT
Crosstalk between target and neighboring spectator qubits due to spillover of control signals represents a major error source limiting the fidelity of two-qubit entangling gates in quantum computers. We show that in our laser-driven trapped-ion system coherent crosstalk error can be modeled as residual Xσ[over ^]_{Ï} interaction and can be actively canceled by single-qubit echoing pulses. We propose and demonstrate a crosstalk suppression scheme that eliminates all first-order crosstalk utilizing only local control of target qubits, as opposed to an existing scheme which requires control over all neighboring qubits. We report a two-qubit Bell state fidelity of 99.52(6)% with the echoing pulses applied after collective gates and 99.37(5)% with the echoing pulses applied to each gate in a five-ion chain. This scheme is widely applicable to other platforms with analogous interaction Hamiltonians.
ABSTRACT
Background: Young children exposed to high-dose vitamin A supplements (VAS) and vitamin A (VA)-fortified foods may be at risk of high VA intake and high VA total body stores (TBS). Objectives: TBS and estimated liver VA concentration were compared among children with adequate or high VA intake and different timing of exposure to VAS, and associations between estimated liver VA concentrations and biomarkers of VA toxicity were examined. Methods: Children 12-18 mo of age (n = 123) were selected for 3 groups: 1) retinol intake >600 µg/d and VAS within the past mo, 2) retinol intake >600 µg/d and VAS in the past 3-6 mo, and 3) VA intake 200-500 µg retinol activity equivalents (RAE)/d and VAS in the past 3-6 mo. Dietary intake data were collected to measure VA intakes from complementary foods, breast milk, and low-dose, over-the-counter supplements. TBS were assessed by retinol isotope dilution, and VA toxicity biomarkers were measured. Main outcomes were compared by group. Results: Mean (95% CI) VA intakes excluding VAS were 1184 (942, 1426), 980 (772, 1187), and 627 (530, 724) µg RAE/d, in groups 1-3, respectively; mean VA intake was higher in groups 1 and 2 compared with group 3 (P < 0.05). Geometric mean (GM) (95% CI) TBS were 589 (525, 661), 493 (435, 559), and 466 (411, 528) µmol, respectively. GM TBS and GM liver VA concentrations were higher in group 1 compared with group 3 (liver VA concentration: 1.62 vs. 1.33 µmol/g; P < 0.05). Plasma retinyl ester and 4-oxo-retinoic acid concentrations and serum markers of bone turnover and liver damage did not indicate VA toxicity. Conclusions: In this sample, most children had retinol intakes above the Tolerable Upper Intake Level (UL) and liver VA concentrations above the proposed cutoff for "hypervitaminosis A" (>1 µmol/g liver). There was no evidence of chronic VA toxicity, suggesting that the liver VA cutoff value should be re-evaluated. This trial was registered at www.clinicaltrials.gov as NCT03030339.