Serum ferritin (SF) concentration is the most widely used indicator for iron deficiency (ID). During pregnancy, the World Health Organization recently recommended SF thresholds for ID of <15 µg/L for the 1st trimester of pregnancy, based on expert opinion, and made no recommendations for the 2nd and 3rd trimesters. We examined the relationship of SF with two independent indicators of the onset of iron-deficient erythropoiesis, hemoglobin (Hb) and soluble transferrin receptor 1 (sTfR1), in cross-sectional data from NHANES for 1999-2010 and 2015-2018. We included 1288 pregnant women 15-49 years and excluded women with inflammation or potential liver disease. We used restricted cubic spline (RCS) regression analysis to determine SF thresholds for iron-deficient erythropoiesis. SF decreased during pregnancy; geometric mean SF was higher during the 1st and lower during the 2nd and 3rd trimesters. Using RCS analysis, the SF thresholds identified during pregnancy were <25.8 (18.1, 28.5) µg/L during 1st trimester, <18.3 (16.3, 22.9) µg/L during 2nd trimester, and <19.0 (14.4, 26.1) µg/L during 3rd trimester. These SF threshold levels track concentrations of hepcidin, the iron regulatory hormone controlling the mobilization of iron stores. A SF concentration of <15 µg/L as the criterion for ID may underestimate the true prevalence of ID throughout pregnancy. In our study, an additional one of every ten pregnant women would be recognized as iron deficient by using the physiologically based thresholds at SF of about 25 µg/L during the 1st and of about 20 µg/L during the 2nd and 3rd trimesters.

We read with interest the article by Kang et al. [1], “Hemoglobin distributions and prevalence of anemia in a multiethnic United States pregnant population,” as well as the accompanying Editorial by Merz and Achebe [2], “Iron deficiency in pregnancy: a health inequity [2].” Both Kang et al. [1] and Merz and Achebe [2] incorrectly stated that the Centers for Disease Control and Prevention (CDC) recommend use of lower race-adjusted thresholds to define anemia for Black individuals. The CDC does not recommend separate diagnostic thresholds to define anemia for Black individuals or any other race/ethnic group. Here, we clarify misinterpretations in recent American Journal of Clinical Nutrition publications regarding the CDC anemia threshold recommendations. | | The 1998 “Recommendations to prevent and control iron deficiency in the United States” [3], the most recent CDC publication providing guidance on thresholds to define anemia in individuals, did not recommend race-specific cutoff values for anemia. The 1998 recommendations included criteria for anemia threshold adjustments based on age, sex, pregnancy status, gestational age, altitude, and smoking status [3]. To guide the development of these 1998 CDC recommendations, the CDC requested that the Institute of Medicine (IOM) convene an expert committee to develop recommendations for preventing, detecting, and treating iron deficiency anemia among children and women of reproductive age in United States. The IOM report published in 1993 [4] is independent and not an official institutional CDC/federal recommendations publication. The 1998 CDC recommendations considered inputs from the IOM report [4], conclusions of a CDC expert panel convened in April 1994, and from other multidisciplinary subject matter experts [3].

We agree with Tamohiko Sato and colleagues that a paucity of ferritin measurements to detect iron deficiency in high-income, middle-income, and low-income countries restricts how well research can quantify the magnitude of the disease burden and prevent and treat the disease. Following Sato and colleagues’ suggestions, we reanalysed ferritin concentration data from the US National Health and Nutrition Examination Survey (NHANES) by age, body-mass index, and income and found no meaningful correlations. In our Article,1 we proposed a method to derive physiologically based ferritin thresholds for iron deficiency among apparently healthy young children and non-pregnant women. We concluded that this approach needs validation in non-US populations before specific threshold values are adopted. Although Sato and colleagues highlight the scarcity of ferritin data for Japan, there is also a paucity of data in the USA for populations at high risk of iron deficiency, hindering surveillance and clinical practice. NHANES measures ferritin but does not collect blood among infants younger than 12 months. Ferritin is an acute phase protein and should be adjusted for inflammation, but NHANES does not measure inflammation in all age groups consistently. Sample sizes for pregnant women are small, requiring the combining of data from approximately 10 years for dependable estimates; after 2013, NHANES stopped recording the trimester of pregnancy. The US Public Health Task Force has also emphasised the paucity of prevalence data for iron deficiency anaemia among pregnant women.2 Analysis of electronic health records for first-trimester pregnancies found that anaemia screening is virtually universal, but ferritin screening for iron deficiency is not,3 despite recommendations by the American College of Obstetrics and Gynecologists.4 We continue to search for suitable anonymised databases to examine the proposed method for deriving physiologically based thresholds for serum ferritin concentration for iron deficiency among apparently healthy individuals. Having found that some national datasets from other countries have prohibitive restrictions on their use, we welcome any suggestions of publicly available and representative ferritin data.

BACKGROUND: In 2004, World Health Organization (WHO) recommended the use of serum ferritin as a primary indicator of iron deficiency. However, there was limited data on the magnitude and distribution of iron deficiency based on ferritin. OBJECTIVE: To describe the prevalence of iron deficiency as measured by serum/plasma ferritin in different regions of the world and its relationship with demographic and health indicators. METHODS: Data from the Biomarkers Reflecting Inflammation and Nutrition Determinants of Anemia and the WHO Vitamin and Mineral Nutrition Information System Micronutrients Database were used for this analysis. Unadjusted and inflammation-adjusted low ferritin prevalence were calculated for both databases. The prevalence of low ferritin among preschool children and non-pregnant women was examined according to its relationship with national gross domestic product (GDP), infant mortality rate (IMR), and anemia rate. RESULTS: In children, the median inflammation-adjusted prevalence of low ferritin was 35.3% (1(st) and 3(rd) quartiles: 17.5% and 48.1%). In non-pregnant women, the median inflammation-adjusted prevalence of low ferritin was 28.4% (1(st) and 3(rd) quartiles: 21.4% and 42.0%). For both children and women, the correlation between the prevalence of low ferritin and GDP, IMR, or anemia was consistently stronger using inflammation-adjusted prevalences than when using unadjusted prevalences. CONCLUSIONS: The quartile values of low ferritin prevalence for children and non-pregnant women could be used to define the severity of ferritin as a public health problem.

Background: Analyses of predictors of anemia or malnutrition often pool national or regional data, which may hide variability at subnational levels. Objectives: We sought to identify the risk factors for anemia in young Nepali children aged 6–23 mo in 2 districts: Kapilvastu and Achham. Methods: This is an analysis of two cross-sectional surveys that were conducted as part of a program evaluation of an infant and young child feeding and micronutrient powder intervention that included anemia as a primary outcome. Baseline and endline surveys in each district (in 2013 and 2016) included hemoglobin assessments in n = 4709 children who were representative of children 6–23 mo in each district. Log-binomial regression models accounting for the survey design were used to estimate univariable and multivariable prevalence ratios for risk factors at multiple levels—underlying, direct, and biological causes. Average attributable fractions (AFs) for the population were calculated for significant predictor biomarkers of anemia in multivariable models. Results: In Accham, the prevalence of anemia was 31.4%; significant predictors included child's age, household asset ownership, length-for-age z-score, inflammation (CRP concentration > 0.5 mg/L; α-1 acid glycoprotein concentration > 1 mg/mL), and iron deficiency (serum ferritin concentration < 12 μg/L with BRINDA-inflammation adjustment). In Kapilvastu, the prevalence of anemia was 48.1%; significant predictors included child's sex and ethnicity, wasting and weight-for-length z-score, any morbidity in the previous 2 wk, consumption of fortified foods, receipt of multiple micronutrient powder distributions, iron deficiency, zinc deficiency (nonfasting serum zinc concentration of <65 μg/dL in the morning and that of <57 μg/dL in the afternoon), and inflammation. In Achham, average AFs were 28.2% and 19.8% for iron deficiency and inflammation, respectively. Average AFs for anemia in Kapilvastu were 32.1%, 4.2%, and 4.9% for iron deficiency, zinc deficiency, and inflammation, respectively. Conclusions: The prevalence of anemia and its risk factors varied between districts, with inflammation contributing to a greater share of anemia in Achham than in Kapilvastu. The estimated AF for iron deficiency was around 30% in both districts; iron-delivering interventions and multisectoral approaches to anemia are warranted. © 2023

BACKGROUND: Current WHO serum ferritin (SF) thresholds for iron deficiency (ID) in children (<12 μg/L) and women (<15 μg/L) are derived from expert opinion based on radiometric assays in use decades ago. Using a contemporary immunoturbidimetry assay, higher thresholds (children, <20 μg/L; women, <25 μg/L) were identified from physiologically based analyses. OBJECTIVE: We examined relationships of SF measured using an immunoradiometric assay from the era of expert opinion with 2 independently measured indicators of ID, hemoglobin (Hb) and erythrocyte zinc protoporphyrin (eZnPP), using data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). The SF at which circulating Hb begins to decrease and eZnPP begins to increase provides a physiological basis for identifying the onset of iron-deficient erythropoiesis. METHODS: We analyzed NHANES III cross-sectional data from 2616 apparently healthy children, aged 12-59 mo, and 4639 apparently healthy nonpregnant women, aged 15-49 y. We used restricted cubic spline regression models to determine SF thresholds for ID. RESULTS: SF thresholds identified by Hb and eZnPP did not differ significantly in children, 21.2 μg/L (95% confidence interval: 18.5, 26.5) and 18.7 μg/L (17.9, 19.7), and, in women, were similar although significantly different, 24.8 μg/L (23.4, 26.9) and 22.5 μg/L (21.7, 23.3). CONCLUSIONS: These NHANES results suggest that physiologically based SF thresholds are higher than the thresholds from expert opinion established during the same era. SF thresholds found using physiological indicators detect the onset of iron-deficient erythropoiesis, whereas the WHO thresholds identify a later, more severe stage of ID.

Iron deficiency and the more severe sequela, iron deficiency anemia, are public health problems associated with morbidity and mortality, particularly among pregnant women and younger children. The 1998 Centers for Disease Control and Prevention recommendations for prevention and control of iron deficiency in the United States is old and does not reflect recent evidence but is a foundational reference for many federal, clinical, and program guidelines. Surveillance data for iron deficiency are sparse at all levels, with critical gaps for pregnant women and younger children. Anemia, iron deficiency, and iron deficiency anemia are often conflated but should not be. Clinical guidelines for anemia, iron deficiency, and iron deficiency anemia give inconsistent recommendations, causing nonsystematic assessment of iron deficiency. Screening for iron deficiency typically relies on identifying anemia, despite anemia's low sensitivity for iron deficiency. In the National Health and Nutrition Examination Survey, more than 70% of iron deficiency is missed among pregnant women and children by relying on hemoglobin for iron deficiency screening. To improve assessment and diagnosis and strengthen surveillance, better and more complete data and updated foundational guidance on iron deficiency and anemia are needed that consider new evidence for measuring and interpreting laboratory results. (Am J Public Health. 2022;112(S8):S826-S835. https://doi.org/10.2105/AJPH.2022.306998).

BACKGROUND: An efficacy evaluation of the AutoAnthro system to measure child (0-59 months) anthropometry in the United States found 3D imaging performed as well as gold-standard manual measurements for biological plausibility and precision. OBJECTIVES: We conducted an effectiveness evaluation of the accuracy of the AutoAnthro system to measure 0- to 59-month-old children's anthropometry in population-based surveys and surveillance systems in households in Guatemala and Kenya and in hospitals in China. METHODS: The evaluation was done using health or nutrition surveillance system platforms among 600 children aged 0-59 months (Guatemala and Kenya) and 300 children aged 0-23 months (China). Field team anthropometrists and their assistants collected manual and scan anthropometric measurements, including length or height, midupper arm circumference (MUAC), and head circumference (HC; China only), from each child. An anthropometry expert and assistant later collected both manual and scan anthropometric measurements on the same child. The expert manual measurements were considered the standard compared to field team scans. RESULTS: Overall, in Guatemala, Kenya, and China, for interrater accuracy, the average biases for length or height were -0.3cm, -1.9cm, and -6.2cm, respectively; for MUAC were 0.9cm, 1.2cm, and -0.8cm, respectively; and for HC was 2.4cm in China. The inter-technical errors of measurement (inter-TEMs) for length or height were 2.8cm, 3.4cm, 5.5cm, respectively; for MUAC were 1.1cm, 1.5cm, and 1.0cm, respectively; and for HC was 2.8cm in China. For intrarater precision, the absolute mean difference and intra-TEM (interrater, intramethod TEM) were 0.1cm for all countries for all manual measurements. For scans, overall, absolute mean differences for length or height were 0.4-0.6cm; for MUAC were 0.1-0.1cm; and for HC was 0.4cm. For the intra-TEM, length or height was 0.5cm in Guatemala and China and 0.7cm in Kenya, and other measurements were0.3cm. CONCLUSIONS: Understanding the factors that cause the many poor scan results and how to correct them will be needed prior to using this instrument in routine, population-based survey and surveillance systems.

BACKGROUND: Portable systems using three-dimensional (3D) scan data to calculate young child anthropometry measurements in population-based surveys and surveillance systems lack acceptability data from field workers and caregivers. OBJECTIVE: The aim was to assess acceptability and experiences with 3D scans measuring child aged 0-59 mo anthropometry in population-based surveys and surveillance systems in Guatemala, Kenya, and China (0-23 mo only) among field teams and caregivers of young children as secondary objectives of an external effectiveness evaluation. METHODS: Manual data were collected twice and 12 images captured per child by anthropometrist/expert and assistant (AEA) field teams (individuals/country, n = 15/Guatemala, n = 8/Kenya, n = 6/China). Caregivers were interviewed after observing their child's manual and scan data collection. Mixed methods included an administered caregiver interview (Guatemala, n = 465; Kenya, n = 496; China, n = 297) and self-administered AEA questionnaire both with closed- and open-ended questions, and 6 field team focus group discussions (FGDs; Guatemala, n = 2; Kenya, n = 3; China, n = 1). Qualitative data were coded by 2 authors and quantitative data produced descriptive statistics. Mixed-method results were compared and triangulated. RESULTS: Most AEAs were female with secondary or higher education. Approximately 80-90% of caregivers were the child's mother. To collect all anthropometry data, 62.1% of the 29 AEAs preferred scan, while 31% preferred manual methods. In FGDs, a key barrier for manual and scan methods was lack of child cooperation. Across countries, approximately 30% to almost 50% of caregivers said their child was bothered by each manual and scan method, while 95% of caregivers were willing to have their child measured by scans in the future. CONCLUSIONS: Use of 3D scans to calculate anthropometry measurements was generally at least as acceptable as manual anthropometry measurement among AEA field workers and caregivers of young children aged <60 mo, and in some cases preferred.

Our objective is to develop a physiologically based method to determine serum ferritin thresholds for iron deficiency in healthy individuals. The current World Health Organization threshold of <15 µg/L for iron deficiency in women is based on expert opinion. We examined the relationship between serum ferritin and two independently measured indicators of iron-deficient erythropoiesis, soluble transferrin receptor (sTfR) and hemoglobin, in baseline data from 286 women, 20-49 years, who were first-time or reactivated donors in the REDS-II Donor Iron Status Evaluation (REDS-RISE) study. At lower serum ferritin concentrations, median sTfR increased as hemoglobin decreased. Using restricted cubic spline regression analysis to determine thresholds for iron-deficient erythropoiesis, the thresholds identified by sTfR (serum ferritin <25.4 µg/L) and by hemoglobin (serum ferritin <25.3 µg/L) did not differ significantly. The thresholds found in the REDS-RISE study do not differ from those identified by sTfR (serum ferritin <25.5 µg/L) and hemoglobin (serum ferritin <26.6 µg/L) in a previous study of 5,442 women, 20-49 years, in the U.S. National Health and Nutrition Examination Survey 2003-2018 (NHANES) (p=0.98 and 0.83, respectively). While international comparisons are needed, these results with US data provide additional evidence for the potential usefulness of a physiologically based method to identify serum ferritin thresholds for iron deficiency.

We used data from the 2016 Nepal National Micronutrient Status Survey to evaluate factors associated with anaemia (World Health Organization cut-points using altitude- and smoking-adjusted haemoglobin [Hb]) among nationally representative samples of adolescents 10-19 years. Hb, biomarkers of micronutrients, infection and inflammation were assessed from venous blood. Sociodemographic and household characteristics, dietary diversity, pica and recent morbidity were ascertained by interview. We explored bivariate relationships between candidate predictors and anaemia among boys (N = 967) and girls (N = 1,680). Candidate predictors with P < 0.05 in bivariate analyses were included in sex-specific multivariable logistic regression models. Anaemia prevalence was 20.6% (95% confidence interval [CI] [17.1, 24.1]) among girls and 10.9% (95% CI [8.2, 13.6]) among boys. Among girls, living in the Mountain and Hill ecological zones relative to the Terai (adjusted odds ratio [AOR] 0.28, 95% CI [0.15, 0.52] and AOR 0.42, 95% CI [0.25, 0.73], respectively), ln ferritin (μg/L) (AOR 0.53, 95% CI [0.42, 0.68]) and ln retinol binding protein (RBP) (μmol/L) (AOR 0.08, 95% CI [0.04, 0.16]) were associated with reduced anaemia odds. Older age (age in years AOR 1.19, 95% CI [1.12, 1.27]) and Janajati ethnicity relative to the Muslim ethnicity (AOR 3.04, 95% CI [1.10, 8.36]) were associated with higher anaemia odds. Among boys, ln RBP [μmol/L] (AOR 0.25, 95% CI [0.10, 0.65]) and having consumed flesh foods (AOR 0.57, 95% CI [0.33, 0.99]) were associated with lower anaemia odds. Open defecation (AOR 2.36, 95% CI [1.15, 4.84]) and ln transferrin receptor [mg/L] (AOR 3.21, 95% CI [1.25, 8.23]) were associated with increased anaemia odds. Anaemia among adolescents might be addressed through effective public health policy and programs targeting micronutrient status, diet and sanitation.

BACKGROUND: The low cost and small specimen volume of the VitMin Lab ELISA assays for serum ferritin (Fer), soluble transferrin receptor (sTfR), C-reactive protein (CRP), and α-1-acid glycoprotein (AGP) allowed their application to micronutrient surveys conducted in low-resource countries for ∼2 decades. OBJECTIVE: We conducted a comparison between the ELISA and reference-type assays used in the US National Health and Nutrition Examination Survey. METHODS: Using the Roche clinical analyzer as a reference, we measured random subsets of the 2016 Nepal National Micronutrient Status Survey (200 serum samples from children 6-59 mo; 100 serum samples from non-pregnant women) for Fer, sTfR, CRP, and AGP. We compared the combined data sets to the ELISA survey results using descriptive analyses. RESULTS: The Lin's concordance coefficients between the 2 assays were ≥ 0.89 except for sTfR (Lin's rho = 0.58). The median relative difference to the reference was: Fer -8.5%, sTfR 71.2%, CRP -19.5%, and AGP -8.2%. The percentage of VitMin samples agreeing within ± 30% of the reference was: Fer 88.5%, sTfR 1.70%, CRP 74.9%, and AGP 92.9%. The prevalence of abnormal results was comparable between the 2 assays for Fer, CRP, and AGP, and for sTfR after adjusting to the Roche assay. Continued biannual performance (2007-2019) of the VitMin assays in CDC's external quality assessment program (6 samples/y) demonstrated generally acceptable performance. CONCLUSION: Using samples from the Nepal survey, the VitMin ELISA assays produced mostly comparable results to the Roche reference-type assays for Fer, CRP, and AGP. The lack of sTfR assay standardization to a common reference material explains the large systematic difference observed for sTfR, which could be corrected by an adjustment equation pending further validation. This snapshot comparison together with the long-term external quality assessment links the survey data generated by the VitMin Lab to the Roche assays used in NHANES.

IMPORTANCE: Anemia, defined as low hemoglobin (Hb) concentration insufficient to meet an individual's physiological needs, is the most common blood condition worldwide. OBJECTIVE: To evaluate the current World Health Organization (WHO) Hb cutoffs for defining anemia among persons who are apparently healthy and to assess threshold validity with a biomarker of tissue iron deficiency and physiological indicator of erythropoiesis (soluble transferrin receptor [sTfR]) using multinational data. DESIGN, SETTING, AND PARTICIPANTS: In this cross-sectional study, data were collected and evaluated from 30 household, population-based nutrition surveys of preschool children aged 6 to 59 months and nonpregnant women aged 15 to 49 years during 2005 to 2016 across 25 countries. Data analysis was performed from March 2020 to April 2021. EXPOSURE: Anemia defined according to WHO Hb cutoffs. MAIN OUTCOMES AND MEASURES: To define the healthy population, persons with iron deficiency (ferritin <12 ng/mL for children or <15 ng/mL for women), vitamin A deficiency (retinol-binding protein or retinol <20.1 μg/dL), inflammation (C-reactive protein >0.5 mg/dL or α-1-acid glycoprotein >1 g/L), or known malaria were excluded. Survey-specific, pooled Hb fifth percentile cutoffs were estimated. Among individuals with Hb and sTfR data, Hb-for-sTfR curve analysis was conducted to identify Hb inflection points that reflect tissue iron deficiency and increased erythropoiesis induced by anemia. RESULTS: A total of 79 950 individuals were included in the original surveys. The final healthy sample was 13 445 children (39.9% of the original sample of 33 699 children; 6750 boys [50.2%]; mean [SD] age 32.9 [16.0] months) and 25 880 women (56.0% of the original sample of 46 251 women; mean [SD] age, 31.0 [9.5] years). Survey-specific Hb fifth percentile among children ranged from 7.90 g/dL (95% CI, 7.54-8.26 g/dL in Pakistan) to 11.23 g/dL (95% CI, 11.14-11.33 g/dL in the US), and among women from 8.83 g/dL (95% CI, 7.77-9.88 g/dL in Gujarat, India) to 12.09 g/dL (95% CI, 12.00-12.17 g/dL in the US). Intersurvey variance around the Hb fifth percentile was low (3.5% for women and 3.6% for children). Pooled fifth percentile estimates were 9.65 g/dL (95% CI, 9.26-10.04 g/dL) for children and 10.81 g/dL (95% CI, 10.35-11.27 g/dL) for women. The Hb-for-sTfR curve demonstrated curvilinear associations with sTfR inflection points occurring at Hb of 9.61 g/dL (95% CI, 9.55-9.67 g/dL) among children and 11.01 g/dL (95% CI, 10.95-11.09 g/dL) among women. CONCLUSIONS AND RELEVANCE: Current WHO cutoffs to define anemia are higher than the pooled fifth percentile of Hb among persons who are outwardly healthy and from nearly all survey-specific estimates. The lower proposed Hb cutoffs are statistically significant but also reflect compensatory increased erythropoiesis. More studies based on clinical outcomes could further confirm the validity of these Hb cutoffs for anemia.

BACKGROUND: Serum ferritin concentrations are the most widely used indicator for iron deficiency. WHO determined that insufficient data are available to revise the serum ferritin thresholds of less than 12 μg/L for children and less than 15 μg/L for women, which were developed on the basis of expert opinion, to define iron deficiency. We aimed to derive new physiologically based serum ferritin concentration thresholds for iron deficiency in healthy young children and non-pregnant women using data from the US National Health and Nutrition Examination Survey (NHANES). METHODS: In this serial cross-sectional study, we examined the relationship of serum ferritin with two independent indicators of iron-deficient erythropoiesis, haemoglobin and soluble transferrin receptor (sTfR), in children (12-59 months) and non-pregnant women (15-49 years) using cross-sectional NHANES data from 2003-06, 2007-10, and 2015-18. NHANES is a US national stratified multistage probability sample that includes a household interview followed by a standardised physical examination in a mobile examination centre. We excluded individuals with missing serum ferritin, sTfR, haemoglobin, or white blood cell counts measurements; non-pregnant women with missing C-reactive protein (CRP), alanine aminotransferase (ALT) or aspartate aminotransferase (AST) data were also excluded. In addition, individuals with infection (white blood cell counts >10·0×10(9)/L) and non-pregnant women with possible liver disease (ALT >70 IU/L or AST >70 IU/L) and inflammation (CRP >5·0 mg/L) were excluded. We examined distributions of haemoglobin and sTfR with serum ferritin and used restricted cubic spline regression models to determine serum ferritin thresholds for iron-deficient erythropoiesis. FINDINGS: 5964 children and 10 462 non-pregnant women had physical examinations and were screened for inclusion in the study, of whom 2569 (43·1%) children and 7498 (71·7%) non-pregnant women were included. At lower serum ferritin concentrations, median haemoglobin concentration decreased as sTfR concentration increased, with each varying in a curvilinear manner. Using restricted cubic spline plateau points to determine the onset of iron-deficient erythropoiesis, the serum ferritin thresholds identified by haemoglobin and sTfR concentrations were not different. For children, the haemoglobin identified serum ferritin threshold was 19·9 μg/L (95% CI 18·8-22·6) and the sTfR identified serum ferritin threshold was 20·0 μg/L (19·4-20·9; p=0·89). For women the haemoglobin identified serum ferritin threshold was 25·2 μg/L (24·2-26·2) and the sTfR identified serum ferritin threshold was 24·0 μg/L (23·3-24·6; p=0·05). INTERPRETATION: The association between two independent indicators of iron-deficient erythropoiesis, haemoglobin and sTfR, identified serum ferritin concentration thresholds of about 20 μg/L for children and 25 μg/L for non-pregnant women, providing physiological evidence of potential new thresholds for consideration when determining the prevalence and distribution of iron deficiency in populations. In healthy children and non-pregnant women, physiologically based thresholds for iron deficiency might be more clinically and epidemiologically relevant than those based on expert opinion. Validation of this physiologically based approach in non-US populations might help the international harmonisation of serum ferritin thresholds for iron deficiency. FUNDING: None.

Short-term in vitro genotoxicity assays are useful tools to assess whether new and emerging tobacco products potentially have reduced toxicity. We previously demonstrated that potency ranking by benchmark dose (BMD) analysis quantitatively identifies differences among several known carcinogens and toxic chemicals representing different chemical classes found in cigarette smoke. In this study, six whole smoke solution (WSS) samples containing both the particulate and gas phases of tobacco smoke were generated from two commercial cigarette brands under different smoking-machine regimens. Sixty test cigarettes of each brand were machine-smoked according to the International Organization for Standardization (ISO) puffing protocol. In addition, either 60 or 20 test cigarettes of each brand were machine-smoked with the Canadian Intense (CI) puffing protocol. All six WSSs were evaluated in the bacterial reverse mutation (Ames) test using Salmonella typhimurium strains, in the presence or absence of S9 metabolic activation. The resulting S9-mediated mutagenic concentration-responses for the four WSSs from 60 cigarettes were then compared using BMD modeling analysis and the mutagenic potency expressed as number of revertants per μl of the WSS. The quantitative approaches resulted in a similar rank order of mutagenic potency for the Ames test in both TA98 and TA100. Under the conditions of this study, these results indicate that quantitative analysis of the Ames test data can discriminate between the mutagenic potencies of WSSs on the basis of smoking-machine regimen (ISO vs. CI), and cigarette product (differences in smoke chemistry).

In this secondary analysis of data from a double-blind randomized controlled trial (clinicaltrials.gov identifier: NCT00133744) of micronutrient supplementation (multiple micronutrients [MMN], iron-folic acid [IFA] and folic acid [FA] alone), we examined the potential modifying effect of gestational age at enrolment on the association of antenatal supplementation and pregnancy-induced hypertension (PIH). We included 18,775 nulliparous pregnant women with mild or no anaemia who were enrolled at 20 weeks of gestation or earlier from five counties of northern China. Women were randomly assigned to receive daily FA, IFA or MMN from enrolment until delivery. We used logistic regression to evaluate the association between PIH and timing of micronutrient supplementation. The incidence of PIH was statistically significantly lower among women who began MMN supplementation before 12 gestational weeks compared with women who began MMN supplementation at 12 weeks or later (RR = 0.74, 95% CI: 0.60-0.91). A similar protective effect was observed for both early-onset (<28 weeks, RR 0.45, 0.21-0.96) and late-onset of PIH (≥28 weeks, RR 0.77, 0.63-0.96). No statistically significant association was observed between PIH occurrence and timing of supplementation for FA or IFA. Maternal MMN supplementation and antenatal enrolment during the first trimester of pregnancy appeared to be of importance in preventing both early- and late-onset of PIH.

Feng Shuren, Mei Joanne, Yang Lu, Luo Ping, Wang Xiaonan, Wang Yuan, Yao Jingyi, Cui Lan, Pan Lei, Wang Zefang, Xin Li. International journal of neonatal screening 2020 Feb 6(1)

Newborn screening (NBS) laboratories cannot accurately compare mass spectrometry-derived results and cutoff values due to differences in testing methodologies. The objective of this study was to assess harmonization of laboratory proficiency test (PT) results using quality control (QC) data. Newborn Screening Quality Assurance Program (NSQAP) QC and PT data reported from 302 laboratories in 2019 were used to compare results among laboratories. QC materials were provided as dried blood spot cards which included a base pool and the base pool enriched with specific concentrations of metabolites in a linear range. QC data reported by laboratories were regressed on QC data reported by the Centers for Disease Control and Prevention (CDC), and laboratory's regression parameters were used to harmonize their PT result. In general, harmonization tended to reduce overall variation in PT data across laboratories. The metabolites glutarylcarnitine (C5DC), tyrosine, and phenylalanine were displayed to highlight inter- and intra-method variability in NBS results. Several limitations were identified using retrospective data for harmonization, and future studies will address these limitations to further assess feasibility of using NSQAP QC data to harmonize PT data. Harmonizing NBS data using common QC materials appears promising to aid result comparison between laboratories.

Ninhydrin-based fluorometric quantification of phenylalanine is one of the most widely used methods for hyperphenylalaninemia (HPA) screening in neonates due to its high sensitivity, high accuracy, and low cost. Here we report an increase of false positive cases in neonatal HPA screening with this method, caused by contamination of blood specimen collection devices during the printing process. Through multiple steps of verification, the contaminants were identified from ink circles printed on the collection devices to indicate the positions and sizes of blood drops. Blood specimens from HPA-negative persons collected on these contaminated collection devices showed positive results in the fluorometric tests, but negative results in tandem mass spectroscopy (MS/MS) experiments. Contaminants on the collection devices could be extracted by 80% ethanol and showed an absorption peak around 245 nm, suggesting that these contaminants may contain benzene derivatives with similar structure to phenylalanine. High-performance liquid chromatography (HPLC) analysis of the ethanol extracts from contaminated collection devices identified two prominent peaks specifically from the devices. Methyl-2-benzoylbenzoate (MBB, CAS#606-28-0) was found as one of the major chemicals from contaminated collection devices. This report aims to remind colleagues in the field of this potential contamination and call for tighter regulation and quality control of specimen collection devices.

BACKGROUND: Small-quantity lipid-based nutrient supplements (SQ-LNS) are efficacious in controlled settings; data are scarce on the effectiveness utilizing health care delivery platforms. OBJECTIVE: We evaluated the impact of an infant young child feeding (IYCF)-SQ-LNS intervention on anemia and growth in children aged 6-18 mo in the Democratic Republic of Congo following a quasi-experimental effectiveness design. METHODS: An intervention health zone (HZ) received enhanced IYCF including improved counseling on IYCF during pregnancy until 12 mo after birth and daily use of SQ-LNS for infants 6-12 mo; the control HZ received the standard IYCF package. We analyzed data from 2995 children, collected in repeated cross-sectional surveys. We used adjusted difference-in-difference analyses to calculate changes in anemia, iron and vitamin A deficiencies, stunting, wasting, and underweight. RESULTS: Of mothers, 70.5% received SQ-LNS at least once in the intervention HZ, with 99.6% of their children consuming SQ-LNS at least once. The mean number of batches of SQ-LNS (28 sachets per batch, 6 batches total) received was 2.3 ± 0.8 (i.e., 64.4 ± 22.4 d of SQ-LNS). The enhanced program was associated with an 11.0% point (95% CI: -18.1, -3.8; P < 0.01) adjusted relative reduction in anemia prevalence and a mean +0.26-g/dL (95% CI: 0.04, 0.48; P = 0.02) increase in hemoglobin but no effect on anthropometry or iron or vitamin A deficiencies. At endline in the intervention HZ, children aged 8-13 mo who received ≥3 monthly SQ-LNS batch distributions had higher anthropometry z scores [length-for-age z score (LAZ): +0.40, P = 0.04; weight-for-age z score (WAZ): +0.37, P = 0.04] and hemoglobin (+0.65 g/dL, P = 0.007) and a lower adjusted prevalence difference of stunting (-16.7%, P = 0.03) compared with those who received none. CONCLUSIONS: The enhanced IYCF-SQ-LNS intervention using the existing health care delivery platform was associated with a reduction in prevalence of anemia and improvement in mean hemoglobin. At endline among the subpopulation receiving ≥3 mo of SQ-LNS, their LAZ, WAZ, and hemoglobin improved. Future research could explore contextual tools to maximize coverage and intake adherence in programs using SQ-LNS.

BACKGROUND: Valid measurement of hemoglobin is important for tracking and targeting interventions. This study compares hemoglobin distributions between surveys matched by country and time from The Demographic and Health Survey (DHS) Program and the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project. METHODS: Four pairs of nationally representative surveys measuring hemoglobin using HemoCue(R) with capillary (DHS) or venous (BRINDA) blood were matched by country and time. Data included 17,719 children (6-59 months) and 21,594 non-pregnant women (15-49 y). Across paired surveys, we compared distributional statistics and anemia prevalence. RESULTS: Surveys from three of the four countries showed substantial differences in anemia estimates (9 to 31 percentage point differences) which were consistently lower in BRINDA compared to DHS (2 to 31 points for children, 1 to 16 points for women). CONCLUSION: We identify substantial differences in anemia estimates from surveys of similar populations. Further work is needed to identify the cause of these differences to improve the robustness of anemia estimates for comparing populations and tracking improvements over time.

We used cross-sectional data from the 2016 Nepal National Micronutrient Status Survey to evaluate factors associated with anaemia among a nationally representative sample of nonpregnant women 15- 49 years (n = 1, 918). Haemoglobin, biomarkers of iron status and other micronutrients, infection, inflammation, and blood disorders were assessed from venous blood. Soil-transmitted helminth and Helicobacter pylori infections were assessed from stool. Sociodemographic, household, and health characteristics and diet were ascertained by interview. We conducted bivariate analyses between candidate predictors and anaemia (haemoglobin <12.0 g/ dL, altitude- and smoking-adjusted). Candidate predictors that were significant in bivariate models (P < 0.05) were included in the multivariable logistic regression model, accounting for complex sampling design. Anaemia prevalence was 20.2% (95% confidence interval [CI] [17.6, 22.8]). Associated with reduced anaemia odds were living in the Mountain and Hill ecological zones relative to the Terai (adjusted odds ratio [AOR] 0.35, 95% CI [0.21, 0.60] and AOR 0.41, 95% CI [0.29, 0.59], respectively), recent cough (AOR 0.56, 95% CI [0.38, 0.82]), hormonal contraceptive use (AOR 0.58; 95% CI [0.38, 0.88]), ln ferritin (micrograms per litre; AOR 0.43, 95% CI [0.35, 0.54]), and ln retinol binding protein (micrograms per litre; AOR 0.20, 95% CI [0.11, 0.37]). Residing in a house with an earth floor (AOR 1.74, 95% CI [1.18, 2.56]), glucose-6- phosphate dehydrogenase deficiency (AOR 2.44, 95% CI [1.66, 3.60]), and haemoglobinopathies (AOR 6.15, 95% CI [3.09, 12.26]) were associated with increased anaemia odds. Interventions that improve micronutrient status, ensure access to hormonal birth control, and replace dirt floors to reduce infection risk might help reduce anaemia in this population.

BACKGROUND: Anemia is a major concern for children in Nepal; however, little is known about context-specific causes of anemia. OBJECTIVE: We used cross-sectional data from the 2016 Nepal National Micronutrient Status Survey to evaluate factors associated with anemia in a nationally representative, population-based sample of children 6-59 mo (n = 1367). METHODS: Hemoglobin, biomarkers of iron status and other micronutrients, infection, inflammation, and blood disorders were assessed from venous blood samples. Soil-transmitted helminth (STH) and Helicobacter pylori infections were assessed from stool. Anthropometry was measured with standard procedures. Sociodemographic and household characteristics, diet, micronutrient powder (MNP) intake, pica, and morbidity recall were ascertained by caregiver interview. Multivariable logistic regression that accounted for complex sampling design, determined predictors of anemia (hemoglobin <11.0 g/dL, altitude adjusted); candidate predictors were variables with P < 0.05 in bivariate models. RESULTS: Anemia prevalence was 18.6% (95% CI: 15.8, 21.4). MNP intake [adjusted OR (AOR): 0.25, 95% CI: 0.07, 0.86], log (ln) ferritin (mug/L) (AOR: 0.49, 95% CI: 0.38, 0.64), and ln RBP (mumol/L) (AOR: 0.42, 95% CI: 0.18, 0.95) were associated with reduced odds of anemia. Younger age (6-23 mo compared with 24-59 mo; AOR: 2.29, 95% CI: 1.52, 3.46), other Terai ethnicities (AOR: 2.59, 95% CI: 1.25, 5.35) and Muslim ethnicities (AOR: 3.15, 95% CI: 1.30, 7.65) relative to Brahmin/Chhetri ethnicities, recent fever (AOR: 1.68, 95% CI: 1.08, 2.59), ln C-reactive protein (mg/L) (AOR: 1.23, 95% CI: 1.03, 1.45), and glucose-6-phosphate dehydrogenase deficiency (AOR: 2.84, 95% CI: 1.88, 4.30) were associated with increased odds of anemia. CONCLUSION: Both nonmodifiable and potentially modifiable factors were associated with anemia. Thus some but not all anemia might be addressed through effective public health policy, programs, and delivery of nutrition and infection prevention and control.

BACKGROUND: Despite the considerable disease burden caused by the disease, rotavirus vaccine has not been introduced into routine national immunization schedule, and norovirus vaccines are being developed without a comprehensive understanding of gastroenteritis epidemiology. To bridge this knowledge gap, we investigated the disease burden of viral gastroenteritis in rural China. METHODS: Between October 2011 and December 2013, population-based surveillance was conducted in Zhengding and Sanjiang counties in China. Stool samples were collected from children <5 years of age with diarrhea. All specimens were tested for rotaviruses, noroviruses, sapoviruses, enteric adenoviruses, and astroviruses. RESULTS: The most common pathogen causing diarrhea was rotavirus (54.7 vs 45.6 cases/1,000 children/year in Zhengding and Sanjiang, respectively), followed by norovirus (28.4 vs 19.3 cases/1,000 children/year in Zhengding and Sanjiang, respectively). The highest incidence of these viruses was observed in children 6-18 months of age. Among the 5 viral pathogens, rotaviruses caused the most severe illness, followed by noroviruses. CONCLUSION: Rotavirus and norovirus are the 2 most important viral pathogens causing childhood diarrhea in both northern and southern China; they should be the major targets for viral gastroenteritis prevention strategies among children in China.

Large-scale programmes using micronutrient powders (MNPs) may not achieve maximum impact due to limited/inappropriate MNP coverage, consumption, and use. We identify predictors of MNP coverage, maternal knowledge of appropriate use, and child MNP consumption in Nepal. A cross-sectional survey was conducted in 2,578 mother-child pairs representative of children 6-23 months in two districts that were part of the post-pilot, scale-up of an integrated infant and young child feeding-MNP (IYCF-MNP) programme. Children aged 6-23 months were expected to receive 60 MNP sachets every 6 months from a female community health volunteer (FCHV) or health centre. Outcomes of interest were MNP coverage (ever received), maternal knowledge of appropriate use (correct response to seven questions), repeat coverage (receipt >/= twice; among children 12-23 months who had received MNP at least once, n = 1342), and high intake (child consumed >/=75% of last distribution, excluding those with recent receipt/insufficient time to use 75% at recommended one-sachet-per-day dose, n = 1422). Multivariable log-binomial regression models were used to identify predictors of the four outcomes. Coverage, knowledge of appropriate use, and repeat coverage were 61.3%, 33.5%, and 45.9%, respectively. Among MNP receivers, 97.9% consumed MNP at least once and 38.9% of eligible children consumed >/=75% of last distribution. FCHV IYCF-MNP counselling was positively associated with knowledge, coverage, repeat coverage, and high intake; health worker counselling with knowledge and coverage indicators; and radio messages with coverage indicators only. FCHV counselling had the strongest association with knowledge, coverage, and high intake. Community-based counselling may play a vital role in improving coverage and intake in MNP programmes.

Genotype I (GI) virus has replaced genotype III (GIII) virus as the dominant Japanese encephalitis virus (JEV) in the epidemic area of Asia. The mechanism underlying the genotype replacement remains unclear. Therefore, we focused our current study on investigating the roles of mosquito vector and amplifying host(s) in JEV genotype replacement by comparing the replication ability of GI and GIII viruses. GI and GIII viruses had similar infection rates and replicated to similar viral titers after blood meal feedings in Culex tritaeniorhynchus. However, GI virus yielded a higher viral titer in amplifying host-derived cells, especially at an elevated temperature, and produced an earlier and higher viremia in experimentally inoculated pigs, ducklings, and young chickens. Subsequently we identified the amplification advantage of viral genetic determinants from GI viruses by utilizing chimeric and recombinant JEVs (rJEVs). Compared to the recombinant GIII virus (rGIII virus), we observed that both the recombinant GI virus and the chimeric rJEVs encoding GI virus-derived NS1-3 genes supported higher replication ability in amplifying hosts. The replication advantage of the chimeric rJEVs was lost after introduction of a single substitution from a GIII viral mutation (NS2B-L99V, NS3-S78A, or NS3-D177E). In addition, the gain-of-function assay further elucidated that rGIII virus encoding GI virus NS2B-V99L/NS3-A78S/E177E substitutions re-gained the enhanced replication ability. Thus, we conclude that the replication advantage of GI virus in pigs and poultry is the result of three critical NS2B/NS3 substitutions. This may lead to more efficient transmission of GI virus than GIII virus in the amplifying host-mosquito cycle.

Analysis of blood phenylalanine is central to the monitoring of patients with phenylketonuria (PKU) and age-related phenylalanine target treatment-ranges (0-12 years; 120-360 mumol/L, and > 12 years; 120-600 mumol/L) are recommended in order to prevent adverse neurological outcomes. These target treatment-ranges are based upon plasma phenylalanine concentrations. However, patients are routinely monitored using dried bloodspot (DBS) specimens due to the convenience of collection. Significant differences exist between phenylalanine concentrations in plasma and DBS, with phenylalanine concentrations in DBS specimens analysed by flow-injection analysis tandem mass spectrometry (FIA-MS/MS) reported to be 18-28% lower than paired plasma concentrations analysed using ion-exchange chromatography (IEC). DBS specimens with phenylalanine concentrations of 360 mumol/L and 600 mumol/L, at the critical upper-target treatment-range thresholds would be plasma equivalents of 461 mumol/L and 768 mumol/L respectively, when a reported difference of 28% is taken into account. Furthermore, analytical test imprecision and bias in conjunction with pre-analytical factors such as volume and quality of blood applied to filter paper collection devices to produce DBS specimens affect the final test results. Reporting of inaccurate patient results when comparing DBS results to target treatment-ranges based on plasma concentrations, together with inter-laboratory imprecision could have a significant impact on patient management resulting in inappropriate dietary change and potentially adverse patient outcomes. This review is intended to provide perspective on the issues related to the measurement of phenylalanine in blood specimens and to provide direction for the future needs of PKU patients to ensure reliable monitoring of metabolic control using the target treatment-ranges. This article is protected by copyright. All rights reserved.

Although the proportion of anemia amenable to change varies by population, the World Health Organization (WHO) criteria used to describe the public health severity of anemia are based on population prevalences. We describe the importance of measuring iron and other etiologic indicators to better understand what proportion of anemia could be responsive to interventions. We discuss the necessity of measuring inflammation to interpret iron biomarkers and documenting anemia of inflammation. Finally, we suggest assessing nonmodifiable genetic blood disorders associated with anemia. Using aggregated results from the Global Burden of Disease 2016, we compare population prevalence of anemia with years lived with disability (YLD) estimates, and the relative contributions of mild, moderate, and severe anemia to YLD. Anemia prevalences correlated with YLD and the relative proportion of moderate or severe anemia increased with anemia prevalence. However, individual-level survey data revealed irregular patterns between anemia prevalence, the prevalence of moderate or severe anemia, and the prevalence of iron deficiency anemia (IDA). We conclude that although the WHO population prevalence criteria used to describe the public health severity of anemia are important for policymaking, etiologic-specific metrics that take into account IDA and other causes will be necessary for effective anemia control policies.

The correct interpretation of hemoglobin (Hb) to identify anemia requires adjusting for altitude and smoking. Current adjustments were derived using data collected before 1985, from low-income preschool-aged children (PSC) in the United States and indigenous men in Peru for altitude, and from White women of reproductive age (WRA) in the United States for smoking. Given the oldness and limited representativeness of these data, we reexamined associations between Hb and altitude and/or smoking using 13 population-based surveys and 1 cohort study each conducted after 2000. All WHO regions except South-East Asia were represented. The dataset included 68,193 observations among PSC (6-59 months) and nonpregnant WRA (15-49 years) with data on Hb and altitude (-28 to 4000 m), and 19,826 observations among WRA with data on Hb and smoking (status or daily cigarette quantity). Generalized linear models were used to assess the robustness of associations under varying conditions, including controlling for inflammation-corrected iron and vitamin A deficiency. Our study confirms that Hb should be adjusted for altitude and/or smoking; these adjustments are additive. However, recommendations for Hb adjustment likely need updating. Notably, current recommendations may underadjust Hb for light smokers and for those residing at lower altitudes and overadjust Hb for those residing at higher altitudes.

This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of +/-7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0 g/L), WHO Colour Scale (0.5-10.0 g/L), paper-based devices (5.0-7.0 g/L), HemoCue(R) Hb-201 (1.0-16.0 g/L) and Hb-301 (0.5-6.0 g/L), and Masimo Pronto(R) (0.3-14.0 g/L) overestimated concentrations; (2) Masimo Radical(R)-7 both under- and overestimated concentrations (0.3-104.0 g/L); and (3) other methods underestimated concentrations (2.0-16.0 g/L). Most mean concentration comparisons varied less than +/-7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within +/-7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within +/-7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.