A Practical Guide to Adjust Micronutrient Biomarkers for Inflammation Using the BRINDA Method

Impacts of a Homestead Food Production Intervention on Anaemia and Micronutrient Deficiencies Among Women and Children in Rural Bangladesh: A Cluster-Randomized Controlled Trial

Micronutrient deficiencies affect over half of young children and two-thirds of reproductive-aged women worldwide. Nutrition-sensitive agriculture interventions have the potential to increase nutrient-dense food intake and thus improve micronutrient status. We evaluated the impact of a homestead food production (HFP) programme on micronutrient status and anaemia of women and their children (registered secondary outcomes) in the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) trial, additionally assessing its impact on inflammation. We conducted a 1:1 parallel two-arm cluster-randomized controlled trial in Sylhet, Bangladesh, with 96 clusters. The 3-year HFP intervention included gardening, poultry, nutrition, and hygiene components. In 2015, we enrolled 2705 women and their children up to 3 years of age, and in 2019, we evaluated impacts on anaemia, iron, vitamin A, zinc and inflammation status through blood measures of women (aged 19-44 years) and their 6- to 37-month-old children, using multilevel regression. Anaemia was common (nonpregnant women: 20%, pregnant women: 35%, children: 16%), while iron deficiency was rare among nonpregnant women (3%), 12% among pregnant women and 20% among children. Vitamin A deficiency ranged from 1% to 5%, and zinc deficiency was very common (nonpregnant women: 43%, pregnant women: 69%, children: 25%). We found no evidence of an intervention impact on micronutrient status, anaemia or inflammation among the 2483 women and 930 children measured. The moderate improvements in dietary intake achieved by the intervention were thus not sufficient, and more substantial hygiene improvements and targeted dietary changes may be needed to improve micronutrient status. This trial was registered at Clinicaltrials.gov (NCT02505711).

Physiologically based serum ferritin thresholds for iron deficiency among women and children from Africa, Asia, Europe, and central America: a multinational comparative study

BACKGROUND

Diagnosis of iron deficiency commonly relies on measurement of serum ferritin concentrations. WHO guidelines identify serum ferritin thresholds for iron deficiency among healthy individuals of less than 15 μg/L for women and less than 12 μg/L for children under 5 years, based on expert opinion. We report thresholds for iron deficiency for apparently healthy non-pregnant women and young children based on physiological indicators.

METHODS

We performed secondary analyses of cross-sectional data from women (aged 15-49 years) and children (aged 6-59 months) from 12 countries in Africa, Asia, Europe, and central America from available surveys (2007-19). Using haemoglobin and soluble transferrin receptor concentrations as individual-level indicators of iron deficiency, we identified country-specific serum ferritin thresholds. We conducted multivariate meta-analysis using individual participant data to assess multinational heterogeneity and intercountry consistency.

FINDINGS

Data were collected from July, 2007 to March, 2019. 18 251 individuals (13 864 women and 4387 children) were included in the final analysis. The thresholds of pooled serum ferritin levels corresponding to the starting point of decline in circulating haemoglobin concentrations were 24·8 μg/L (95% CI 24·4-25·2) for women and 22·1 μg/L (20·8-23·4) for children based on the national survey data from 12 countries. The thresholds were consistent among countries (pheterogeneity: women=0·73, children=0·43) but median serum ferritin concentrations and lower 5% reference ranges differed. In all countries, the prevalence of iron deficiency was higher using physiologically based thresholds than that using WHO current guidelines for women (36·0% [95% CI 25·3-46·8] vs 20·1% [11·5-28·7], p<0·0001) and for children (34·2% [24·3-44·1] vs 16·6% [11·2-22·0], p<0·0001).

INTERPRETATION

These results provide evidence that the prevalence of iron deficiency as indicated by physiological measures is substantially higher than those based on current WHO guidelines. The consistency of physiologically based serum ferritin thresholds in apparently healthy women and young children offers a potential means to achieve evidence-informed coordination in thresholds for iron deficiency across populations. The use of physiologically based serum ferritin thresholds could help in detecting the clinical and functional outcomes of iron deficiency.

FUNDING

None.

The ABCDs of Nutritional Assessment in Infectious Diseases Research

Malnutrition is the most common acquired cause of immunodeficiency worldwide. Nutritional deficiencies can blunt both the innate and adaptive immune response to pathogens. Furthermore, malnutrition is both a cause and consequence of infectious diseases. The bidirectional relationship between infectious diseases and undernutrition, as well as the inflammatory milieu of infectious diseases, can complicate nutritional assessment. This article aims to provide clinicians and researchers with an overview of commonly used tools to assess nutritional status, with a particular emphasis on their use in the context of infectious diseases. These tools include anthropometric, biochemical, clinical/physical, and dietary assessments to screen and evaluate undernutrition, diet quality, and food insecurity effectively.

Food Insecurity, Anemia and Vitamin A Deficiency in Brazilian Children Aged between 6 and 59 Months of Age: Brazilian National Survey on Child Nutrition (ENANI-2019)

Background

Anemia and vitamin A deficiency (VAD) can be related to poverty and food insecurity (FI), which can increase risk of stunting and delayed child development.

Objectives

This study aims to assess the association between FI and the occurrence of anemia and VAD in Brazilian children aged 6-59 months.

Methods

Data from 6020 children from the Brazilian National Survey on Child Nutrition (2019) were used. FI was assessed using the Brazilian Food Insecurity Scale, classifying households into food security (FS) and FI levels. The outcomes were anemia [hemoglobin <10.5 g/dL (6-23 months) and hemoglobin <11 g/dL (24-59 months)] and VAD (retinol corrected by C-reactive protein <0.7 μmol/L). FI frequencies, anemia, and VAD prevalences were calculated according to FI levels, 95% confidence intervals (CIs), and P-trend. The adjusted prevalence ratio (PR) was estimated using quasi-Poisson regression.

Results

The prevalence of mild, moderate, and severe FI was 37.7% (95% CI: 32.0%, 43.4%), 6.2% (95% CI: 4.8%, 7.6%), and 4.2% (95% CI: 3.1%, 5.3%), respectively. The prevalence of anemia was 7.1% (95% CI: 5.9%, 8.3%), and VAD was 3.0% (95% CI: 2.5%, 3.6%). A significant linear trend (P-trend < 0.001) was observed in the prevalence of anemia according to the degree of FI: severe (15.5%; 95% CI: 8.1%, 22.9%), moderate (10.0%; 95% CI: 5.4%, 14.6%), mild (6.6%; 95% CI: 4.9%, 8.3%), and FS (6.4%; 95% CI: 4.7%, 8.1%). Children living in households with severe FI had an 82% higher prevalence of anemia (PR: 1.82; 95% CI: 1.40, 4.17) than those living in FS. A significant linear trend (P-trend < 0.001) was observed in the prevalence of VAD according to the degree of FI: severe (3.3%; 95% CI: 0.0%, 6.7%), moderate (5.8%; 95% CI: 2.3%, 9.2%), FI (2.8%; 95% CI: 1.9%, 3.7%), and FS (2.9%; 95% CI: 2.1%, 3.7%). No association was observed between FI and VAD.

Conclusions

Severe FI was associated with anemia among Brazilian children aged 6-59 months.

Association Between Dietary Inflammatory Index and Triglyceride Glucose-Body Mass Index with Iron Deficiency in Reproductive Age Women: Evidence from NHANES 2005-2018

Background & Aims

There is a growing focus on the role of dietary factors and metabolic conditions in the evolution and progression of iron deficiency (ID), yet few studies have examined the underlying mechanisms. Dietary Inflammatory Index (DII) is a metric that gauges the inflammatory potential of an overall diet. This study explores the association between DII and triglyceride glucose-body mass index (TyG-BMI) with ID in reproductive-age women.

Methods

This analysis utilized data from 2311 reproductive-age women in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. ID was identified using serum ferritin and transferrin receptor (TfR). The association between DII, TyG-BMI and ID was assessed using weighted logistic regression, linear regression and restricted cubic spline (RCS) models, with receiver operating characteristic (ROC) curve analysis for diagnostic power. Mediation effects of TyG-BMI were further explored by causal mediation analysis.

Results

Among reproductive-age women, both DII and TyG-BMI were significantly positively associated with ID (DII: OR = 1.32, 95% CI 1.19, 1.48; TyG-BMI: OR = 1.13, 95% CI 1.02, 1.35). There is a close relationship between the DII index and TfR (β= 1.17, 95% CI 1.03, 1.13). RCS analysis indicated that the relationships were mostly linear (P-overall < 0.05, P-nonlinear > 0.05). Furthermore, TyG-BMI mediated 5.19%, 12.83%, and 5.63% of the associations between DII and ID, Ferritin, and transferrin receptor (TfR), respectively.

Conclusion

The findings suggest that targeted interventions to enhance dietary practices, nutritional intake, and overall metabolic well-being may result in substantial amelioration of ID among reproductive women.

Vitamin C-Rich Guava Consumed with Mungbean Dal Reduces Anemia and Increases Hemoglobin but not Iron Stores: A Randomized Controlled Trial of Food-to-Food Fortification in Indian Children

BACKGROUND

Adding vitamin C-rich fruit to staples containing iron could be an effective strategy to improve iron bioavailability and thereby reduce iron-deficiency anemia in children.

OBJECTIVES

We aimed to assess the effect of consuming a mungbean-based meal with or without guava fruit on body iron stores, hemoglobin concentration, and anemia of children as part of a school feeding program.

METHODS

We conducted a 7-mo randomized, controlled trial with 6- to 10-y-old school children (n = 200; 46% anemic, 71% iron-deficient) from a rural community in Haryana, North India. Children were assigned to 2 treatment groups to daily receive either a meal of mungbean dal only (3.0 mg iron; vitamin C:iron molar ratio ∼0.5:1), or mungbean dal with fresh guava (3.2 mg iron; ∼170 mg vitamin C; molar ratio ∼18:1). Meals were served every school day under supervision. The primary outcome was body iron stores, whereas concentrations of hemoglobin and other iron indicators were secondary outcomes.

RESULTS

Daily consumption of mungbean dal along with guava did not result in an overall improvement of body iron stores [mean treatment effect: 0.65 mg/kg body weight; 95% confidence interval (CI): -0.34, 1.63; P = 0.197]. However, compared with children who consumed mungbean dal only, children in the guava group showed a larger increase in hemoglobin concentration (3.7 g/L; 95% CI: 1.6, 5.6; P = 0.001), and a larger drop in the prevalence of anemia (-51%; 95% CIs: -74, -10; P = 0.022) and iron-deficiency anemia (-56%, 95% CI: -83, 13; P = 0.087). These effects were more pronounced in children who were iron deficient at study start.

CONCLUSIONS

Addition of guava to a mungbean-based meal containing a moderate amount of iron increased hemoglobin and reduced anemia but did not provide enough additional absorbed iron to also increase body iron stores. Food-to-food fortification by inclusion of vitamin C-rich fruits in iron-containing school meals may help alleviate the burden of anemia in children.

TRIAL REGISTRATION NUMBER

This trial was registered at https://clinicaltrials.gov/ct2/show/NCT01191463.

A systematic review and meta-analysis of the association between neglected tropical diseases and malnutrition: more research needed on diseases other than intestinal parasites, leishmaniasis and leprosy

Background. According to the World Health Organization, neglected tropical diseases (NTDs) affect over two billion people worldwide. While the links between nutrition and many diseases have become clear over recent decades, NTDs have lagged behind and the linkage with nutrition is largely unknown. We conducted this systematic review with meta-analysis to determine the current knowledge on the association between NTDs and malnutrition. Methodology. PubMed, Embase, Scopus and African Journals Online databases were searched using predefined search terms. We included all original articles with a case-control design and at least one NTD. The studies had to compare nutritional parameters between infected cases and control participants. Articles that did not report original data were excluded. The quality of the studies was assessed using the Newcastle-Ottawa scale. Pooled estimates were conducted using the random effect model. The publication bias of the studies was determined by funnel plots. Q and I 2 statistics were used to assess the heterogeneity of the studies. Results. After screening 1294 articles, only 16 qualified for the systematic review and 12 for meta-analysis. These predominately had a focus on soil-transmitted helminthiasis (ascariasis, hookworm diseases and trichuriasis) and schistosomiasis, with a minority concerning leishmaniasis and leprosy. Pooled estimates showed an association between intestinal parasites and stunting in children [odds ratio (OR) = 1.38, 95% confidence interval (CI): 1.14-1.66, I 2 = 0%, tau2 = 0]. We also identified a moderate association established between serum iron deficiency (OR = 4.67, 95% CI: 1.91-11.44, tau2 = 0) and intestinal parasites. Conclusions/significance. Of the 20 NTDs, the links between diet and disease have been explored for only 4. There is a paucity of data from low- and middle-income countries and least-developed countries where the NTD burden is high. Therefore, more research into the role of malnutrition in NTDs other than intestinal parasites, leishmaniasis and leprosy is needed.

Current or recent malaria infection is associated with elevated inflammation-adjusted ferritin concentrations in pre-school children: a secondary analysis of the BRINDA database

Inflammation and infections such as malaria affect micronutrient biomarker concentrations and hence estimates of nutritional status. It is unknown whether correction for C-reactive protein (CRP) and α1-acid glycoprotein (AGP) fully captures the modification in ferritin concentrations during a malaria infection, or whether environmental and sociodemographic factors modify this association. Cross-sectional data from eight surveys in children aged 6-59 months (Cameroon, Cote d'Ivoire, Kenya, Liberia, Malawi, Nigeria and Zambia; n 6653) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anaemia (BRINDA) project were pooled. Ferritin was adjusted using the BRINDA adjustment method, with values < 12 μg/l indicating iron deficiency. The association between current or recent malaria infection, detected by microscopy or rapid test kit, and inflammation-adjusted ferritin was estimated using pooled multivariable linear regression. Age, sex, malaria endemicity profile (defined by the Plasmodium falciparum infection prevalence) and malaria diagnostic methods were examined as effect modifiers. Unweighted pooled malaria prevalence was 26·0 % (95 % CI 25·0, 27·1) and unweighted pooled iron deficiency was 41·9 % (95 % CI 40·7, 43·1). Current or recent malaria infection was associated with a 44 % (95 % CI 39·0, 52·0; P < 0·001) increase in inflammation-adjusted ferritin after adjusting for age and study identifier. In children, ferritin increased less with malaria infection as age and malaria endemicity increased. Adjustment for malaria increased the prevalence of iron deficiency, but the effect was small. Additional information would help elucidate the underlying mechanisms of the role of endemicity and age in the association between malaria and ferritin.

Serum hepcidin recalibrated values in Mexican schoolchildren by demographic characteristics, nutritional and infection/inflammation status

Hepcidin production is regulated by iron concentration, erythropoietic activity, and inflammation. There is no reference method for determining its levels, but results obtained through various methods strongly correlate and can be compared using recalibration equations.

OBJECTIVE

To describe recalibrated serum hepcidin values at different percentiles in schoolchildren, considering age, sex, inflammatory processes, H. pylori infection, and iron status.

METHODS

Secondary analysis of data incorporating information on inflammation, H. pylori infection, and iron status of 349 schoolchildren. Hepcidin analysis was performed using a competitive ELISA, and recalibrated hepcidin values were calculated using the inverse of the linear regression model equation obtained by van der Vorm et al. Results: Recalibrated hepcidin values were lower than non-calibrated values. In schoolchildren without infection/inflammation and without iron deficiency, recalibrated values at the 50th percentile (25th-75th) were 4.89 ng/mL (2.68-8.42). For schoolchildren without infection/inflammation but with iron deficiency, recalibrated values were 2.34 ng/mL (1.10-6.58), the lowest hepcidin values observed. The highest values were found in the group with infection/inflammation, regardless of iron deficiency status.

CONCLUSIONS

Recalibrated hepcidin values were lower than non-calibrated values. The highest values were observed in schoolchildren with infectious or inflammatory processes, and the lowest values were observed in schoolchildren with iron deficiency but only in the absence of infectious or inflammatory processes. Using recalibrated hepcidin values allows comparison between data obtained using different analytical methods.

Iron status and anemia in a representative sample of US pregnant women is not associated with pre-pregnancy BMI: Results from the NHANES (1999-2010) study

Iron deficiency in pregnancy is related to many poor health outcomes, including anemia and low birth weight. A small number of previous studies have identified maternal body mass index (BMI) as a potential risk factor for poor iron status. Our objective was to examine the association between pre-pregnancy BMI, iron status, and anemia in a nationally representative sample of US adult women. We used data from the National Health and Nutrition Examination Survey (NHANES; 1999-2010) for pregnant women ages 18-49 years (n = 1156). BMI (kg/m2) was calculated using pre-pregnancy weight (self-reported) and height (measured at examination). Iron deficiency (ID) was defined as total body iron (calculated from serum ferritin and transferrin receptor using Cook's equation) < 0 mg/kg and anemia as hemoglobin < 11 g/dL. Associations were examined using weighted linear and Poisson regression models, adjusted for confounders (age, race/ethnicity, education, and trimester). Approximately 14% of pregnant women had ID and 8% had anemia in this sample. Ferritin and total body iron trended slightly lower (p = 0.12, p = 0.14) in women with pre-pregnancy BMI in the normal and overweight categories compared to the underweight and obese categories; hemoglobin concentrations were similar across BMI groups (p = 0.76). There were no differences in the prevalence of ID or anemia in women with pre-pregnancy overweight and obesity (ID: overweight, adjusted prevalence ratio (PR) = 1.27, 95%CI: 0.89-1.82; obesity, PR = 0.75, 95%CI: 0.39-1.45; anemia: overweight, PR = 1.08, 95%CI: 0.53-2.19; obesity, PR = 0.99, 95%CI: 0.49-2.01) compared to women with a normal BMI. Findings from these US nationally representative data indicate that total body iron, serum hemoglobin, ID, and anemia in pregnancy do not differ by pre-pregnancy BMI. Since ID and anemia during pregnancy remain significant public health concerns, NHANES should consider measuring current iron status in upcoming cycles.

Micronutrient deficiencies and the double burden of malnutrition in Vietnamese female adolescents: a national cross-sectional study in 2020

Background

Vietnam is facing a double burden of malnutrition, with increasing prevalence of overweight coexisting with undernutrition (stunting and/or thinness) and micronutrient deficiencies (MNDs). Although malnutrition during female adolescence leads to poor health outcomes with potential intergenerational effects on offspring, no studies have comprehensively investigated MNDs and nutritional status among contemporary Vietnamese female adolescents.

Methods

Data from 10- to 18-year-old female participants (n = 1471) in the nationally-representative Vietnam General Nutrition Survey 2020 were analysed. Blood nutritional biomarkers, anthropometric measurements, and sociodemographic data were collected, and associations between nutrition status and MNDs were analysed; with anaemia, iron deficiency (ID), iron deficiency anaemia, low serum zinc, low serum retinol, and any MNDs as specified outcomes.

Findings

Prevalence of overweight, stunting, and thinness was 27.2%, 14.3%, and 6.9%, respectively. Low serum zinc was common (39.8%), as was ID (13.4%). Bivariate analyses showed that older age (16-18 years old), ethnic minority status, lower wealth index, and inflammation were associated with MNDs. In adjusted logistic regressions, stunting was associated with increased odds ratio and [95% confidence intervals] of low serum retinol (8.92 [2.26, 35.15], p < 0.01), as was thinness (12.25 [3.47, 43.33], p < 0.01). Stunting was also associated with increased odds of having any MND (2.06 [1.31, 3.25], p < 0.01).

Interpretation

More female adolescents were overweight than undernourished in Vietnam in 2020. However, undernutrition, low serum zinc, and ID remain prevalent. Food systems approaches should be considered to stem the stark increase in the double burden of malnutrition in young people living in Vietnam.

Funding

UK BBSRCBB/T008989/1.

Interactions of Nutrition and Infection: The Role of Micronutrient Deficiencies in the Immune Response to Pathogens and Implications for Child Health

Approximately five million children die each year from preventable causes, including respiratory infections, diarrhea, and malaria. Roughly half of those deaths are attributable to undernutrition, including micronutrient deficiencies (MNDs). The influence of infection on micronutrient status is well established: The inflammatory response to pathogens triggers anorexia, while pathogens and the immune response can both alter nutrient absorption and cause nutrient losses. We review the roles of vitamin A, vitamin D, iron, zinc, and selenium in the immune system, which act in the regulation of molecular- or cellular-level host defenses, directly affecting pathogens or protecting against oxidative stress or inflammation. We further summarize high-quality evidence regarding the synergistic or antagonistic interactions between MNDs, pathogens, and morbidity or mortality relevant to child health in low- and middle-income countries. We conclude with a discussion of gaps in the literature and future directions for multidisciplinary research on the interactions of MNDs, infection, and inflammation.

Baby Food Pouches, Baby-Led Weaning, and Iron Status in New Zealand Infants: An Observational Study

Iron deficiency in infants can impact development, and there are concerns that the use of baby food pouches and baby-led weaning may impair iron status. First Foods New Zealand (FFNZ) was an observational study of 625 New Zealand infants aged 6.9 to 10.1 months. Feeding methods were defined based on parental reports of infant feeding at "around 6 months of age": "frequent" baby food pouch use (five+ times per week) and "full baby-led weaning" (the infant primarily self-feeds). Iron status was assessed using a venepuncture blood sample. The estimated prevalence of suboptimal iron status was 23%, but neither feeding method significantly predicted body iron concentrations nor the odds of iron sufficiency after controlling for potential confounding factors including infant formula intake. Adjusted ORs for iron sufficiency were 1.50 (95% CI: 0.67-3.39) for frequent pouch users compared to non-pouch users and 0.91 (95% CI: 0.45-1.87) for baby-led weaning compared to traditional spoon-feeding. Contrary to concerns, there was no evidence that baby food pouch use or baby-led weaning, as currently practiced in New Zealand, were associated with poorer iron status in this age group. However, notable levels of suboptimal iron status, regardless of the feeding method, emphasise the ongoing need for paying attention to infant iron nutrition.

Potential Drug-Nutrient Interactions of 45 Vitamins, Minerals, Trace Elements, and Associated Dietary Compounds with Acetylsalicylic Acid and Warfarin-A Review of the Literature

In cardiology, acetylsalicylic acid (ASA) and warfarin are among the most commonly used prophylactic therapies against thromboembolic events. Drug-drug interactions are generally well-known. Less known are the drug-nutrient interactions (DNIs), impeding drug absorption and altering micronutritional status. ASA and warfarin might influence the micronutritional status of patients through different mechanisms such as binding or modification of binding properties of ligands, absorption, transport, cellular use or concentration, or excretion. Our article reviews the drug-nutrient interactions that alter micronutritional status. Some of these mechanisms could be investigated with the aim to potentiate the drug effects. DNIs are seen occasionally in ASA and warfarin and could be managed through simple strategies such as risk stratification of DNIs on an individual patient basis; micronutritional status assessment as part of the medical history; extensive use of the drug-interaction probability scale to reference little-known interactions, and application of a personal, predictive, and preventive medical model using omics.

Serum Zinc Concentrations by Inflammation Status, Time of Day, and Fasting Status for Estimating Zinc Deficiency in 6-59-Mo-Old Children: Results from the Brazilian National Survey on Child Nutrition (ENANI-2019)

BACKGROUND

Serum zinc concentration (SZC) is considered the best biomarker of zinc status in population-level evaluations. However, zinc deficiency (ZD) estimations can be biased if they do not consider blood collection timing, inflammation, and fasting status.

OBJECTIVES

The objectives of this study were to determine SZC without and with adjustment for inflammation, according to blood collection timing and fasting status, estimate ZD prevalence, and evaluate the associated factors with ZD in a representative sample of Brazilian children aged <5 y.

METHODS

Population-based study with 7597 children aged 6-59 mo surveyed by the Brazilian National Survey on Child Nutrition. SZC was adjusted for inflammation using the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia regression correction approach, with high-sensitive C-reactive protein, assessed according to blood collection timing (morning/afternoon) and fasting status (<8 and ≥8 h). SZC <65 μg/dL (morning collection) or SZC <57 μg/dL (afternoon collection) were classified as ZD. The analysis between associated factors and ZD used the adjusted prevalence ratio (PR).

RESULTS

After adjusting for inflammation, SZC was higher in all percentiles and varied according to collection timing and fasting status. Children who had blood collected in the morning without fasting or in the afternoon had lower SZC than those assessed in the morning with fasting. The differences in adjusted SZC according to the timing of collection and fasting status were greater in the higher percentiles of the distribution, with the greatest absolute difference observed when comparing the 95th percentile of morning fasting compared with nonfasting (20.3 μg/dL). The prevalence of ZD estimated without and with adjusting SZC for inflammation was 17.8% and 13.8%, respectively. The occurrence of diarrhea, fever, or respiratory symptoms in the 15 d before blood collection was associated with a higher prevalence of ZD (PR: 1.42; 95% confidence interval: 1.04, 1.94).

CONCLUSIONS

Adjusting SZC for inflammation and considering fasting status is important to avoid overestimating the prevalence of ZD.

Manganese and Sleep Outcomes in United States Adults: Results from the 2017-2020 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Manganese (Mn) is an essential micronutrient, but inadequate or excess Mn intake can have a detrimental impact on human health. Despite the essentiality, little is known about the relationship between Mn and sleep.

OBJECTIVE

This study aimed to examine the relationship between blood Mn concentrations and sleep outcomes in US adults.

METHODS

This cross-sectional study used data on blood Mn and sleep from the 2017-2020 National Health and Nutrition Examination Survey (NHANES) (n = 8356, age ≥18 y). Multivariable logistic regression was used to examine associations between quintiles of blood Mn concentrations and subjective sleep outcomes (short sleep duration, late sleep midpoint, trouble sleeping, and obstructive sleep apnea [OSA] symptoms), adjusting for age, gender, body mass index, race/ethnicity, income, smoking, inflammation-adjusted serum ferritin concentration (iron status), caffeine, and alcohol intake. Gender-stratified models were used due to interactions with gender.

RESULTS

The mean (SE) blood Mn concentration was 9.7 (0.1) μg/L in US adults. In males, a nonlinear association was noted in the relationship between blood Mn levels and short sleep duration on weekdays and weekends. The third Mn quintile (Q3) group had lower odds of short sleep duration (<7 h) on weekdays (odds ratio [OR]=0.6, 95% confidence interval [CI]: 0.4, 0.9) than the lowest Mn quintile (Q1, reference) after adjusting for covariates in males. The second Mn quintile (Q2) group had lower odds of late sleep midpoint on weekdays than Q1 (OR=0.6, 95% CI: 0.4, 0.8). In females, Q2 group had lower odds of OSA symptoms than Q1 (OR: 0.6, 95% CI: 0.4, 0.9). No relationship was noted between Mn and trouble sleeping.

CONCLUSIONS

Gender differences exist in the association between Mn and sleep in adults. Q1 group had the poorest sleep outcomes, including higher odds of short sleep duration (in males), late sleep midpoint (in males), and OSA symptoms (in females).

Micronutrients and socio-demographic factors were major predictors of anaemia among the Ethiopian population

Anaemia is characterised by low hemoglobin (Hb) concentration. Despite being a public health concern in Ethiopia, the role of micronutrients and non-nutritional factors as a determinant of Hb concentrations has been inadequately explored. This study focused on the assessment of serum micronutrient and Hb concentrations and a range of non-nutritional factors, to evaluate their associations with the risk of anaemia among the Ethiopian population (n 2046). It also explored the mediation effect of Zn on the relation between se and Hb. Bivariate and multivariate regression analyses were performed to identify the relationship between serum micronutrients concentration, inflammation biomarkers, nutritional status, presence of parasitic infection and socio-demographic factors with Hb concentration (n 2046). Sobel-Goodman test was applied to investigate the mediation of Zn on relations between serum se and Hb. In total, 18·6 % of participants were anaemic, 5·8 % had iron deficiency (ID), 2·6 % had ID anaemia and 0·6 % had tissue ID. Younger age, household head illiteracy and low serum concentrations of ferritin, Co, Cu and folate were associated with anaemia. Serum se had an indirect effect that was mediated by Zn, with a significant effect of se on Zn (P < 0·001) and Zn on Hb (P < 0·001). The findings of this study suggest the need for designing a multi-sectorial intervention to address anaemia based on demographic group.

Streamlining Micronutrient Biomarker Statistical Analysis in Populations: An Introduction to the SAMBA R Package

Micronutrient deficiency is a common global health problem, and accurately assessing micronutrient biomarkers is crucial for planning and managing effective intervention programs. However, analyzing micronutrient data and applying appropriate cutoffs to define deficiencies can be challenging, particularly when considering the confounding effects of inflammation on certain micronutrient biomarkers. To address this challenge, we developed the Statistical Apparatus of Micronutrient Biomarker Analysis (SAMBA) R package, a new tool that increases ease and accessibility of population-based micronutrient biomarker analysis. The SAMBA package can analyze various micronutrient biomarkers to assess status of iron, vitamin A, zinc, and B vitamins; adjust for inflammation; account for complex survey design when appropriate; and produce reports of summary statistics and prevalence estimates of micronutrient deficiencies using recommended age-specific and sex-specific cutoffs. In this study, we aimed to provide a step-by-step procedure for how to use the SAMBA R package, including how to customize it for broader use, and made both the package and user manual publicly available on GitHub. SAMBA was validated by comparing results by analyzing 24 data sets on nonpregnant women of reproductive age from 23 countries and 30 data sets on preschool-aged children from 26 countries with those obtained by an independent analyst. SAMBA generated identical means, percentiles, and prevalence of micronutrient deficiencies to those calculated by the independent analyst. In conclusion, SAMBA simplifies and standardizes the process for deriving survey-weighted and inflammation-adjusted (when appropriate) estimates of the prevalence of micronutrient deficiencies, reducing the time from data cleaning to result generation. SAMBA is a valuable tool that facilitates the accurate and rapid analysis of population-based micronutrient biomarker data, which can inform public health research, programs, and policy across contexts.