[This corrects the article DOI: 10.1016/j.cdnut.2026.107692.].

Background Nutritional biomarkers are used as objective measures of nutritional status to inform public health strategies. The relationship between dietary intake and biomarkers varies across population subgroups due to biological, demographic, and behavioral factors. Understanding these differences is important for identifying nutritional interventions. Objective We evaluated how sociodemographic, lifestyle, and physiologic factors modify the association between vitamin-specific dietary intake (food and supplements) and selected water- and fat-soluble vitamin biomarkers among U.S. adults aged ≥20 y. Methods Data were used from the 2003–2006 National Health and Nutrition Examination Survey for selected biomarkers (serum folate (SFOL), red blood cell folate (RBF), pyridoxal-5’-phosphate (PLP), vitamins B12, A (VIA), C (VIC), E (VIE), and 25-hydroxyvitamin D) and either vitamin-specific dietary intake (24-h dietary recall) or self-reported supplement use (past 30 d). Demographic, lifestyle, and physiologic variables were: age, sex, race and Hispanic origin, education, poverty level, serum cotinine, alcohol use, physical activity, body mass index, estimated glomerular filtration rate, and serum C-reactive protein. Associations between vitamin-specific intake and biomarkers were assessed using both bivariate analyses and multivariable linear regression models accounting for the clustered sampling design. Results In unadjusted models, supplement use explained (R2) from 3% (VIA) to 21% (SFOL) and dietary intake explained from 0.8% (VIE) to 8.8% (VIC) of the biomarker variability. Intake models indicated more confounding due to sociodemographic and physiologic variables. Supplement use models demonstrated heterogeneous effects across subgroups (i.e., effect modification by age, sex, and race and Hispanic origin). After full adjustment, both dietary intake and supplement use were independently associated with biomarkers for all vitamins except for vitamin A intake and all supplement use associations changed direction except for SFOL and RBF. Conclusions These findings highlight the need to include supplement use and account for heterogeneous demographic effects when interpreting intake–biomarker associations in models.

BACKGROUND:Pregestational diabetes increases the risk of adverse outcomes including congenital malformations, stillbirth, developmental disabilities, and maternal morbidity. Periconceptional glycemic control and folic acid (FA) supplementation are 2 of the most effective birth defects prevention strategies. OBJECTIVES:The objectives are to describe the proportion of and risk factors for diabetes and prediabetes and assess the association of folate status and diabetes among a nationally representative sample of nonpregnant women of reproductive age (WRA). METHODS:WRA (12‒49 y) from the NHANES 2011‒March 2020 (n = 3731) were included. Diabetes status was defined by glycated hemoglobin (HbA1c) ≥6.5%, fasting plasma glucose (FPG) ≥126 mg/dL, or self-report. Prediabetes was defined as HbA1c ≥5.7 <6.5% or FPG ≥100 <126 mg/dL. The associations were assessed by multivariate regression models. RESULTS:Among all WRA, 32.3% [95% confidence interval (CI): 30.0%, 34.7%] had prediabetes and 5.3% (95% CI: 4.4%, 6.3%) had diabetes [1.8% undiagnosed, 95% CI: 1.4%, 2.3%; 3.1% diagnosed but uncontrolled (HbA1c ≥5.7), 95% CI: 2.5, 4.0; 0.4% diagnosed but controlled (HbA1c<5.7), 95% CI: 0.2, 0.6]. The prevalence of diabetes was associated with increased age, BMI, serum pyrazino-s-triazine, an oxidation form of 5'-methyltetrahydrofolate (MeFox), and red blood cell (RBC) folate concentrations (all P < 0.0001) but not unmetabolized FA. Among WRA ≥35 y, 10.5% (95% CI: 8.5%, 12.8%) had diabetes and 40.3% (95% CI: 37.1%, 43.5%) had prediabetes. In adjusted regression models, diabetes was associated with altered folate metabolism [i.e., high (>90th %) RBC folate concentrations with lower (<400 μg/d) FA intake; adjusted odds ratio 2.28 (95% CI: 1.23, 4.24)]. Among those with diabetes, high serum MeFox and RBC folate concentrations were lower with euglycemia. CONCLUSIONS:Diabetes and prediabetes were common among WRA. Diabetes was associated with high RBC folate concentration and high MeFox despite low FA intake; however, these associations were reduced among those with good glycemic control. Screening for and preventing the progression of prediabetes, diagnosis, and glycemic control among those with diabetes has the potential to prevent adverse outcomes.

Centers for Disease Control and Prevention's 'National Report on Biochemical Indicators of Diet and Nutrition in the US Population' provides nutritional status assessment by presenting blood and urine concentrations of diet and nutrition biomarkers in a representative sample of the US population ≥1 y participating in the NHANES. Earlier reports contained information for 27 (1999-2002) and 58 (2003-2006) biomarkers. We aimed to provide an overview of the 2026 report, which covers data for ≤131 biomarkers since 1999, with 50 biomarkers from August 2021 to August 2023. Concentrations over time by cycle are stratified by dietary supplement use, reference interval concentrations focus on tail percentiles, and concentrations grouped by age, sex, and/or race and Hispanic origin demonstrate demographic differences. The report is intended for agencies and organizations involved in developing nutrition policies and monitoring their effects. It provides easily accessible, comprehensive nutritional biomarker data for the US population during the last 24 y.

Information is limited regarding the response of serum folate forms (FOL-forms) to intake of folic acid (FA)-fortified foods. A randomized, 3-arm, dose-response trial of nonpregnant Ethiopian females assessed the effect of double-fortified salt containing iodine and FA on folate status. This report focuses on changes in FOL-forms {5-methyltetrahydrofolate (5-methylTHF), unmetabolized FA (UMFA), nonmethyl folate (NMFOL; sum of 3 minor FOL-forms), and the oxidation product of 5-methylTHF [pyrazino-s-triazine derivative of 4α-hydroxy-5-methyltetrahydrofolate (MeFox)]} after consumption of iodized salt (IS), lower FA IS (LFS; ∼200 μg additional FA/d), or higher FA IS (HFS; ∼600 μg additional FA/d) from baseline to endline ∼6 mo later. At endline, median concentrations of 5-methylTHF, UMFA, NMFOL, and MeFox were significantly different among treatment arms in a dose-response manner, whereas no differences were observed at baseline [5-methylTHF: 5.1-fold (HFS), 3.2-fold (LFS) baseline to endline increase]. The response of serum FOL-forms to the intervention was consistent with limited information from previous supplementation trials. This trial was registered at clinicaltrials.gov as NCT06223854; https://clinicaltrials.gov/study/NCT06223854?term=NCT06223854&viewType=Card&rank=1.

An interlaboratory comparison study was conducted among five laboratories for determining 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in human serum using liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The Centers for Disease Control and Prevention (CDC), Imperial College Healthcare NHS Trust, University College Cork, University of Liège, and University of Washington analyzed 50 single-donor samples and two new Standard Reference Materials (SRMs®). The results from each laboratory were compared with target values assigned by the National Institute of Standards and Technology (NIST) using a reference measurement procedure (RMP) and evaluated using Ordinary Deming linear regression and Bland-Altman analysis. Three of the five laboratory methods provided results that were in good agreement with the NIST RMP results showing linear regression slopes ranging from 0.972 to 1.003 and Bland-Altman mean bias of −0.092 nmol/L, 0.025 nmol/L, and 0.035 nmol/L. Two laboratories demonstrated a significant positive bias with linear regression slopes of 1.158 and 1.214 and Bland-Altman mean bias of 0.162 nmol/L and 0.708 nmol/L. The CDC method is currently used to assign “information only” values for 24,25(OH)2D3 in the quarterly distributions of the Vitamin D External Quality Assessment Scheme (DEQAS). Given the agreement (linear regression slope = 0.984, R2 = 0.996 and mean bias of −0.092 nmol/L) between the CDC method and the NIST RMP observed in this study, the CDC-assigned 24,25(OH)2D3 values in DEQAS may provide a more accurate reference than the current participant consensus mean values.

Background:Red blood cell (RBC) total folate (TFOL) is an indicator of long-term folate status. Data on RBC folate forms are lacking. They may inform associations with health-related indicators. Objectives:We aimed to describe associations between RBC folate forms and different factors in the United States population. Methods:We used data for 5 biologically active RBC folate forms [5-methyltetrahydrofolate (5-methylTHF), unmetabolized folic acid (UMFA), tetrahydrofolate (THF), 5-formyltetrahydrofolate (5-formylTHF), and 5,10-methenyltetrahydrofolate (5,10-methenylTHF); sum of which is TFOL] and 1 oxidation product of 5-methylTHF (MeFox) in persons aged ≥6 y participating in the National Health and Nutrition Examination Survey 2021-2023 cycle. We excluded pregnant or lactating females. We assessed bivariate associations between folate biomarkers [concentrations for TFOL, 5-methylTHF, THF, and MeFox; prevalences ≥limit of detection (LOD) for UMFA, 5-formylTHF, and 5,10-methenylTHF] and demographic, physiologic, and lifestyle variables in persons ≥20 y, accounting for the complex sample design. We estimated the impact of covariates on biomarker concentrations or odds ratios after covariate adjustment. Results:In persons ≥6 y (n=7126), geometric mean concentrations (nmol/L) were 913 (TFOL), 835 (5-methylTHF), 26.3 (THF), and 161 (MeFox); prevalences ≥LOD (%) were 43.6 (UMFA), 40.6 (5-formylTHF), and 73.0 (5,10-methenylTHF); and contributions to RBC TFOL were 92.7% (5-methylTHF), 5.02% (THF), and 1.61% (5,10-methenylTHF), varying by race/Hispanic origin. In persons ≥20 y, fasting status was not associated with biomarker concentrations or the prevalence ≥LOD. Biomarkers were significantly associated before and after covariate adjustment with age (TFOL; 5-methylTHF; THF; 5,10-methenylTHF), sex (MeFox), race/Hispanic origin (TFOL; 5-methylTHF; THF; MeFox), body mass index (TFOL; 5-methylTHF), tobacco use (TFOL; THF; MeFox), and folic acid supplement use (TFOL; 5-methylTHF; THF; MeFox; 5-formylTHF; 5,10-methenylTHF). Covariates explained ≤21% of the variation of 5-methylTHF, THF, or MeFox concentrations. Conclusions:Folic acid supplement use was the strongest predictor of RBC folate biomarker concentrations and detection. Differences in the methyl-to-nonmethyl makeup of RBC TFOL by race/Hispanic origin suggest potential biological and/or genetic influences.

Background:Nutritional biomarkers are used as objective measures of nutritional status to inform public health strategies. The relationship between dietary intake and biomarkers varies across population subgroups due to biological, demographic, and behavioral factors. Understanding these differences is important for identifying nutritional interventions. Objectives:We evaluated how sociodemographic, lifestyle, and physiologic factors modify the association between vitamin-specific dietary intake (food and supplements) and selected water- and fat-soluble vitamin biomarkers among US adults aged ≥20 y. Methods:Data were used from the 2003 to 2006 National Health and Nutrition Examination Survey for selected biomarkers [serum folate (SFOL), red blood cell folate (RBF), pyridoxal-5'-phosphate, vitamins B-12, A (VIA), C (VIC), E (VIE), and 25-hydroxyvitamin D] and either vitamin-specific dietary intake (24-h dietary recall) or self-reported supplement use (past 30 d). Demographic, lifestyle, and physiologic variables were: age, sex, race and Hispanic origin, education, poverty level, serum cotinine, alcohol use, physical activity, body mass index, estimated glomerular filtration rate, and serum C-reactive protein. Associations between vitamin-specific intake and biomarkers were assessed using both bivariate analyses and multivariable linear regression models accounting for the clustered sampling design. Results:In unadjusted models, supplement use explained (R 2) from 3% (VIA) to 21% (SFOL) and dietary intake explained from 0.8% (VIE) to 8.8% (VIC) of the biomarker variability. Intake models indicated more confounding due to sociodemographic and physiologic variables. Supplement-use models demonstrated heterogeneous effects across subgroups (i.e., effect modification by age, sex, and race and Hispanic origin). After full adjustment, both dietary intake and supplement use were associated with biomarkers for all vitamins except for vitamin A intake and all supplement-use associations changed direction except for SFOL and RBF. Conclusions:These findings highlight the need to include supplement use and account for heterogeneous demographic effects when interpreting intake-biomarker associations in models.

Background:Tracking the prevalence of imbalances for essential nutrients over time provides insight into nutritional status changes and highlights vulnerabilities of demographic subgroups. Consolidated information for a broad range of biomarkers in the US population is missing. Objectives:We aimed to describe nutritional deficiency and excess prevalence trends for 12 biomarkers of water- and fat-soluble vitamins and iron status in the US population participating in the NHANES 1999-2023 after adjusting for demographic changes over time. Methods:We estimated the prevalence of deficiency (vitamins A, B-6, B-12, C, D, and E, as well as iron), insufficiency [vitamins B-6, B-9 (folate), B-12, C, and D], and excess (vitamins A and D as well as iron). We assessed trends as overall change in prevalence using logistic regression (unadjusted and adjusted for age, sex, and race/Hispanic origin) and as linear trend (if overall change was significant). Results:After adjusting for demographic changes, we observed small (typically <5 percentage points) temporal changes (significant linear trends) in the prevalence of deficiency and/or insufficiency for vitamin B-12 and methylmalonic acid (≥20 y), and for vitamin E and 25-hydroxyvitamin D (25OHD) (≥6 y). The prevalence of folate insufficiency (red blood cell folate (RBF) <748 nmol/L) and iron deficiency (ferritin ≤15 ng/mL) increased from 15.7% to 21.4% and from 11.6% to 17.4%, respectively, in women of reproductive age. The prevalence of excess vitamin D (25OHD >125 nmol/L) increased from <1% to 8.06% in persons ≥6 y, with the highest prevalence in adult subgroups (16.2% in supplement users, 13.2% in females, and 12.3% in non-Hispanic White persons). Conclusions:The large increases in excess 25OHD concentrations and modest increases in low ferritin and RBF concentrations merit attention and highlight the importance of providing gold standard data to continuously monitor the nutritional status of the US population and of subpopulations.

Background Diagnosing low vitamin B12 status is important to reduce megaloblastic anemia and neurological disorders. The lack of a highly specific and sensitive clinical marker and questions about appropriate cutoffs hamper early detection. Objectives We evaluated the predictive power of 3 conventional markers for inadequate vitamin B12 status (total cobalamin [B12], methylmalonic acid [MMA], and total homocysteine [tHcy]) using the combined B12 indicator, 3cB12 (≤-0.5), as a reference. Additionally, we derived optimum cutoffs for each conventional marker and compared the prevalence to that from traditional cutoffs. Design Using National Health and Nutrition Examination Survey (NHANES) 1999–2004 data for B12, MMA, and tHcy for persons ≥20 y with normal renal function, we devised a training set (1999–2002, n=7,469) to derive new optimum cutoffs and a validation set (2003–2004, n=3,641) to test them. All analyses were weighted and accounted for clustered design. Results In the training set, the area under the curve (AUC) for MMA was 0.963, followed by B12 (0.944) and tHcy (0.937); it further increased with 2- and 3-marker models (0.985–0.998). In the validation set, the diagnostic accuracy (Youden’s index) for the new optimum cutoffs was 0.80 for MMA >229 nmol/L and 0.69 for B12 <220 pmol/L and tHcy >10.4 μmol/L. Among the traditional cutoffs, the Youden’s index varied (0.30–0.79); B12 <126 or <148 pmol/L and MMA >376 nmol/L had the highest specificity (>99%). The latter also had reasonable sensitivity (54.9%) and generated an apparent (2.35%) and a sensitivity/specificity-adjusted prevalence (2.48%) close to the 3cB12 reference estimate (2.74%). Conclusions When using a single marker, MMA >376 nmol/L may be a useful cutoff for healthy populations with low (<5%) prevalence of inadequate vitamin B12 status to minimize false positives, whereas MMA >229 nmol/L may be preferred for screening higher-risk groups to detect more cases.

CDC’s National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population provides nutritional status assessment by presenting blood and urine concentrations of diet-and-nutrition biomarkers in a representative sample of the U.S. population ≥1 y participating in the National Health and Nutrition Examination Survey (NHANES). Earlier reports contained information for 27 (1999–2002) and 58 (2003–2006) biomarkers. We aim to provide an overview of the 2026 report, which covers data for ≤131 biomarkers since 1999, with 50 biomarkers from August 2021–August 2023. Concentrations over time by cycle are stratified by dietary supplement use, reference interval concentrations focus on tail percentiles, and concentrations grouped by age, sex, and/or race/Hispanic origin demonstrate demographic differences. The report is intended for agencies and organizations involved in developing nutrition policies and monitoring their effects. It provides easily accessible, comprehensive nutritional biomarker data for the U.S. population during the last 24 y.

Background:The National Health and Nutrition Examination Survey (NHANES) has monitored biomarkers for 4 key nutrients important for pregnancy outcomes, neurological development, and healthy growth-folate, vitamin D, iodine, and iron-during most survey cycles from 1999 to 2000 through August 2021-August 2023 as part of the continuous NHANES. These biomarker data offer a unique opportunity to assess long-term trends in the US population. Objectives:This study aimed to describe concentration trends for 7 biomarkers/indicators after adjusting for demographic changes over time. Methods:We used the following NHANES data: serum folate (SFOL) and red blood cell folate (RBF) for persons aged ≥3 y and women of reproductive age (WRA, 12-49 y) for 1999-August 2023 (except 2017-2018), serum 25-hydroxyvitamin D (25OHD) for persons aged ≥3 y for 2001-August 2023, urine iodine (UI) for persons aged ≥3 y for 2001-2018, and serum ferritin [(FER) and FER adjusted for inflammation (FERadj)], serum soluble transferrin receptor, and body iron index (BII) for WRA and children aged 1-5 y for 2003-August 2023 (except 2011-2014). We assessed trends as overall concentration change using logistic regression (unadjusted and adjusted for age, sex, and race and Hispanic origin) and as a linear trend if the overall change was significant. Results:After adjusting for demographic changes, mean concentrations of all 7 biomarkers/indicators showed significant overall temporal changes (except for FER in children and BII in WRA) and significant linear trends (except for FERadj in children). SFOL (∼25%-30%), RBF (∼10%), and UI (∼25%-30%) concentrations decreased, whereas 25OHD (∼20%) concentrations increased. FER concentrations decreased in WRA (∼15%) and remained unchanged in children. Conclusions:Considering the long monitoring period, biomarker changes were moderate. Nonetheless, these changes highlight the need to address declining iodine, iron, and folate status in WRA and increasing vitamin D status in supplement users.

Background:Diagnosing low vitamin B-12 status is important to reduce megaloblastic anemia and neurological disorders. The lack of a highly specific and sensitive clinical marker and questions about appropriate cutoffs hamper early detection. Objectives:We evaluated the predictive power of 3 conventional markers for inadequate vitamin B-12 status [total cobalamin (B-12), methylmalonic acid (MMA), and total homocysteine (tHcy)] using the combined vitamin B-12 indicator, 3cB-12 (≤-0.5), as a reference. Additionally, we derived optimum cutoffs for each conventional marker and compared the prevalence with that from traditional cutoffs. Methods:Using NHANES 1999-2004 data for vitamin B-12, MMA, and tHcy for persons ≥20 y with normal renal function, we devised a training set (1999-2002, n = 7469) to derive new optimum cutoffs and a validation set (2003-2004, n = 3641) to test them. All analyses were weighted and accounted for clustered design. Results:In the training set, the area under the curve for MMA was 0.963, followed by B-12 (0.944) and tHcy (0.937); it further increased with 2- and 3-marker models (0.985-0.998). In the validation set, the diagnostic accuracy (Youden's index) for the new optimum cutoffs was 0.80 for MMA >229 nmol/L and 0.69 for vitamin B-12 <220 pmol/L and tHcy >10.4 μmol/L. Among the traditional cutoffs, Youden's index varied (0.30-0.79); vitamin B-12 <126 or <148 pmol/L and MMA >376 nmol/L had the highest specificity (>99%). The latter also had reasonable sensitivity (54.9%) and generated an apparent (2.35%) and a sensitivity/specificity-adjusted prevalence (2.48%) close to the 3cB-12 reference estimate (2.74%). Conclusions:When using a single marker, MMA >376 nmol/L may be a useful cutoff for healthy populations with low (<5%) prevalence of inadequate vitamin B-12 status to minimize false positives, whereas MMA >229 nmol/L may be preferred for screening higher-risk groups to detect more cases.

The omega-3 index (O3I; sum of red blood cell (RBC) concentrations of eicosapentaenoic and docosahexaenoic acid) is strongly correlated with risk for sudden cardiac death. We aim to provide nationally representative data on the prevalence of O3I undesirable (<4%), intermediate (4–8%), and optimal (>8%) categories in the U.S. population ages ≥6 y and determine associations with selected sociodemographic, lifestyle, intake, and health variables among adults. 54% of U.S. persons ages ≥6 y (n=7213) had an undesirable O3I; the mean O3I was 4.12% and it increased with age. Among adults ≥20 y (n=5721), the O3I was higher in females, non-Hispanic Asians, persons above the poverty line, those with education beyond high school, non-smokers, polyunsaturated fatty acid supplement users, cholesterol-lowering drug users, and persons with healthy weight or certain heart health conditions. These first data demonstrate that the U.S. population falls short of dietary recommendations to achieve an optimal O3I. Teaser Text This manuscript presents the prevalence of omega-3 index categories in the U.S. population and assesses associations with sociodemographic, lifestyle, and health variables in adults.

The omega-3 index (O3I; defined as the sum of red blood cell concentrations of eicosapentaenoic acid and docosahexaenoic acid) is strongly correlated with the risk for sudden cardiac death. We aimed to provide nationally representative data on the prevalence of undesirable (<4%), intermediate (4%-8%), and optimal (>8%) O3I categories in the United States population aged ≥6 y and to determine associations with selected sociodemographic, lifestyle, intake, and health variables among adults. Fifty-four percent of United States persons aged ≥6 y (n = 7213) had an undesirable O3I; the mean O3I was 4.12%, and it increased with age. Among adults ≥20 y (n = 5721), the O3I was higher in females, non-Hispanic Asians, persons above the poverty line, those with education beyond high school, nonsmokers, PUFA supplement users, cholesterol-lowering drug users, and persons with a healthy weight or certain heart health conditions. These first data demonstrate that the United States population falls short of dietary recommendations required to achieve an optimal O3I.

Several essential vitamins and minerals whose deficiencies are associated with metabolic and functional disorders, including increased morbidity and mortality from both communicable and noncommunicable diseases, are not being adequately addressed by large-scale, public health nutrition programs worldwide. These neglected micronutrients include thiamine, riboflavin, niacin, pyridoxine, vitamin B-12, vitamin D, vitamin K, calcium, selenium, and possibly others. In this narrative review, our objectives are to describe briefly the health implications of each of these deficiencies, summarize the limited available information on their epidemiology, and suggest possible approaches to address them. We conclude that more information, based on dietary assessments, nutritional biomarker surveys, and systematic surveillance of associated health conditions, is needed. Appropriate intervention programs, including changes in food systems to provide wider access to nutrient-rich foods, food fortification and targeted supplementation, should be implemented in settings where these deficiencies are confirmed.

Introduction: The effect of prolonged storage (12-19 years) on selected laboratory test results is examined in the National Health and Nutrition Examination Survey biospecimen collection to determine whether biospecimens stored long term in vapor-phase liquid nitrogen provide valid results once remeasured.Methods: Biospecimens were selected for remeasurement using systematic random sampling for five analytes: cotinine, methylmalonic acid (MMA), vitamin A, vitamin E, and hepatitis C virus RNA (HCV-RNA). Measurements from the original specimens in 1999-2000 or 2005-2006 are compared with 2018-2019 measurements from the same survey participants and specimens. For quantitative analytes, measurement accuracy is assessed using standard method comparison procedures, precision is evaluated by comparing to quality control standards, and reproducibility is estimated by treating data like an incurred sample reanalysis. Qualitative measures are analyzed using concordance measures and exact binomial tests.Results: Observed proportional differences are 3%-12% for cotinine in people who do not smoke, 11% for cotinine in people who smoke, -8% to 1% for vitamin A, 8%-9% for vitamin E, and -6% to 8% for MMA. Precision estimates are within the standards established by quality control data and generally applicable quality goals. Differences between measurements are within 20% of the average value for at least 85% of all samples. For qualitative HCV-RNA and MMA results, we observe 99% concordance between measurements.Conclusions: Multipronged analysis showed that most differences are within acceptable ranges based on standard laboratory criteria for assessing accuracy, precision, and reproducibility. Results suggest future measurements and subsequent statistical analyses of stored serum specimens should be valid.

Population risk for neural tube defects (NTDs) can be determined using red blood cell (RBC) folate. However, a paucity of biomarker and surveillance data among non-lactating, non-pregnant women of reproductive age (NPWRA) from Africa limits accurate assessment. Our study assessed folate and vitamin B12 status among non-lactating NPWRA and predicted population risk of NTDs in Tanzania. A cross-sectional biomarker survey of non-lactating NPWRA (15–49 years) in the Morogoro region, Tanzania was conducted during June–October 2019. Questionnaire interview responses and non-fasting blood samples were collected. Folate was assessed using the CDC microbiologic assay kit and vitamin B12 was measured using an electrochemiluminescence immunoassay. Complex survey design analyses were conducted using SAS-callable SUDAAN (v11.0.1). Of the 761 participating non-lactating NPWRA, 294 (39.8

Background:Folate plays a critical role during pregnancy, preventing neural tube defects and possibly adverse neurodevelopment. Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that may decrease folate levels. Although some studies have found associations between PFAS and folate, we are unaware of studies conducted in pregnant women. To address this knowledge gap, we evaluated associations between PFAS and whole blood folate (WBF) in pregnant women. Methods:We used data from 288 pregnant women in the Health Outcomes and Measures of the Environment (HOME) Study, a pregnancy and birth cohort in the Cincinnati Ohio area. We measured eight serum PFAS and WBF concentrations at 16 weeks' gestation. We used linear regression to estimate the effect of each PFAS on WBF, and quantile-based g-computation and Bayesian kernel machine regression (BKMR) to investigate the joint effect of PFAS on WBF, adjusting for parity, prenatal vitamin intake, maternal race/ethnicity, household income, maternal age, and second trimester smoking status in all models. In addition, we investigated interactions between PFAS using BKMR. Results:We did not observe inverse associations of individual PFAS or their mixture with WBF, nor interactions between PFAS in the BKMR model in pregnant women. Conclusion:Future studies could consider WBF measures in late pregnancy to evaluate other periods of susceptibility. Furthermore, as people are exposed to multiple PFAS, future studies should continue to consider joint PFAS exposure.

BACKGROUND AND AIMS:In clinical populations, vitamin B12 deficiency has been associated with adverse metabolic health (e.g., gestational diabetes). Population-level data among women of reproductive age could inform screening and interventions. The objective of this analysis was to examine the prevalence of adverse metabolic characteristics (elevated adiposity and central adiposity, hypertension, elevated glycated hemoglobin [HbA1c]) and associations of vitamin B12 status with metabolic characteristics in women as part of a population-based biomarker survey in Southern India. METHODS:Participants (n = 980 women 15-40 y; not pregnant or lactating) were assessed for total vitamin B12, holotranscobalamin, methylmalonic acid, homocysteine, and HbA1c. Categorical anthropometry assessments and bioelectrical impedance analysis (e.g., whole body (WF%) and trunk (TF%) fat) were assessed among adults (≥18 y). Linear and binomial regressions were used to examine associations of vitamin B12 status with metabolic characteristics. RESULTS:Overall, 25 % of participants had HbA1c ≥5.7 % (HbA1c ≥5.7-<6.5 %: 20.0 %; ≥6.5 %: 5.0 %), and 18.6 % had hypertension (Stage 1: 16.4 %; Stage 2: 2.2 %). Among adults, 23.4 % had body mass index of (BMI) 25.0-<30.0 kg/m2, 9.6 % had BMI ≥30.0 kg/m2, 13.4 % had elevated waist circumference (WC; >88.9 cm), and 20.8 % had elevated waist-hip ratio (WHR; ≥0.85 cm). Overall, higher vitamin B12 concentrations were associated with lower BMI and WC. Among adults, higher vitamin B12 concentrations were associated with lower WF% and TF%; and lower prevalence of overweight (BMI ≥25.0 kg/m2) and elevated WC, WHR, and WF%. Similarly, vitamin B12 <148 pmol/L was associated with higher BMI and WC overall and, among adults, higher WF% and TF%, and increased overweight (BMI ≥25.0 kg/m2; prevalence ratio: 1.31; 95 % confidence interval: 1.09-1.58), and elevated WC (>88.9 cm; 1.85 [1.32-2.60]), WHR (≥85.0; 1.38 [1.07-1.78]), WF% (>35 %; 1.29 [1.10-1.51]), and TF% (>35 %; 1.25 [1.06-1.49]). CONCLUSIONS:The burden of adverse metabolic characteristics was substantial in this population of young, apparently healthy women. Among those with vitamin B12 <148 pmol/L there was increased central adiposity and overweight status. Evaluating vitamin B12 and metabolic outcomes prospectively could inform screening and interventions to improve women's health. REGISTRATION NUMBER:NCT04048330.