Illustration of the Importance of Adjustment for within- and between-Person Variability in Dietary Intake Surveys for Assessment of Population Risk of Micronutrient Deficiency/Excess Using an Example Data Set.

Nutrition intervention decisions should be evidence based. Single 24-h recalls are often used for measuring dietary intake in large dietary studies. However, this method does not consider the day-to-day variation in populations' diets. We illustrate the importance of adjustment of single 24-h recall data to remove within-person variation using the National Cancer Institute method to calculate usual intake when estimating risk of deficiency/excess. We used an example data set comprising a single 24-h recall in a total sample of 1326 1-<10-year-old children, and two additional recalls in a sub-sample of 11%, for these purposes. Results show that risk of deficiency was materially overestimated by the single unadjusted 24-h recall for vitamins B12, A, D, C and E, while risk of excess was overestimated for vitamin A and zinc, when compared to risks derived from usual intake. Food sources rich in particular micronutrients seemed to result in overestimation of deficiency risk when intra-individual variance is not removed. Our example illustrates that the application of the NCI method in dietary surveys would contribute to the formulation of more appropriate conclusions on risk of deficiency/excess in populations to advise public health nutrition initiatives when compared to those derived from a single unadjusted 24-h recall.

Assessment of the contribution of industrially processed foods to salt and iodine intake in Thailand.

Iodization of food grade salt has been mandated in Thailand since 1994. Currently, processed food consumption is increasing, triggered by higher income, urbanization, and lifestyle changes, which affects the source of salt and potentially iodized salt among the population. However, adequate information about the use of iodized salt in processed foods in Thailand is still lacking. Therefore, this study aimed to assess iodine intake through salt-containing processed foods and condiments which were identified using national survey data. Potential iodine intake from iodized salt in food products was modelled using consumption data and product salt content from food labelling and laboratory analysis. Fish sauce, soy sauce and seasoning sauces (salty condiments) have alternative regulation allowing for direct iodization of the final product, therefore modelling was conducted including and excluding these products. Daily salt intake from household salt and food industry salt (including salty condiments) was estimated to be 2.4 g for children 0-5 years of age, 4.6 g for children 6-12 years of age, and 11.5 g for adults. The use of iodized salt in processed foods (excluding salty condiments) met approximately 100% of the estimated average requirement (EAR) for iodine for non-pregnant adults and for children 6 to 12 years of age, and 50% of the EAR for iodine for children aged 0 to 5 years of age. In all cases, iodine intake from processed food consumption was greater than from estimated household iodized salt consumption. Findings suggest that iodized salt from processed foods is an important source of iodine intake, especially in adults. The use of iodized salt by the food industry should be enforced along with population monitoring to ensure sustainability of optimal iodine intake. Currently, the addition of iodine into fish sauce, soy sauce and seasoning sauces has an important role in achieving and sustaining optimal iodine intake.

Anthropometric assessment in ambulatory nutrition amid the COVID-19 pandemic: Possibilities for the remote and in-person care.

BACKGROUND AND AIMS: The COVID-19 pandemic has caused many changes in the nutritional care process as a result of the social distancing measures imposed, especially in the assessment of nutritional status, in which obtaining anthropometric measures is necessary. METHODS: Critical review of the international anthropometry literature, in the light of the recent scientific evidence of COVID-19. RESULTS: This paper presents recommendations for anthropometric assessment of the nutritional status of people in ambulatory settings for both remote and in-person assessment. The most appropriate measures to the current pandemic scenario are also discussed, in order to contribute to the monitoring of nutritional status and to minimize health impacts.results CONCLUSION: When sanitary conditions cannot be guaranteed during in-person encounters or when the person cannot attend the office of the professional, the remote anthropometric assessment can be a useful strategy to nutritional surveillance.

Nutritional status assessment in patients with Covid-19 after discharge from the intensive care unit.

INTRODUCTION: The nutritional diagnosis and early nutritional management of COVID-19 patients must be integrated into the overall therapeutic strategy. The aim of our study is to assess the nutritional status of patients with COVID-19 after a stay in intensive care, to describe the prevalence of undernutrition, to determine the factors influencing undernutrition and to describe the nutritional management. TOOLS AND METHODS: This is a descriptive observational study of adult patients admitted to the endocrinology service for additional care after a stay in intensive care during the period from April 17, 2020 to May 26, 2020. The assessment tool used was the Mini Nutritional Assessment (MNA). RESULTS: Our study included 41 patients; the average age of the patients was 55 years, 51.2% had a severe or critical form of COVID-19, 75.6% stayed in intensive care, 12.2% had a loss of autonomy. The average BMI was 25.2 kg/m2 (17-42 kg/m2), 42.5% were overweight, 61% had weight loss, 26.2% had weight loss greater than 10%, 14.6% of our patients were undernourished, 65.9% were at risk of undernutrition, 19.5% had hypoalbuminemia, 17.1% had hypoprotidemia, 19.5% hypocalcemia, 34.1% anemia, 12.2% hypomagnesemia and 51.2% had a deficiency in vitamin D. A positive correlation was found between poor nutritional status and a longer stay in intensive care (>5 days) (p = 0.011) and lymphopenia (p = 0,02). CONCLUSION: Despite a personalized diet, 14.6% of patients presented undernutrition. Particular attention should be paid to patients with a long stay in intensive care.

Benefits and Harms of a Prevention Program for Iodine Deficiency Disorders: Predictions of the Decision-Analytic EUthyroid Model.

Background: Iodine deficiency is one of the most prevalent causes of intellectual disability and can lead to impaired thyroid function and other iodine deficiency disorders (IDDs). Despite progress made on eradicating iodine deficiency in the last decades in Europe, IDDs are still prevalent. Currently, evidence-based information on the benefit/harm balance of IDD prevention in Europe is lacking. We developed a decision-analytic model and conducted a public health decision analysis for the long-term net benefit of a mandatory IDD prevention program for the German population with moderate iodine deficiency, as a case example for a European country. Methods: We developed a decision-analytic Markov model simulating the incidence and consequences of IDDs in the absence or presence of a mandatory IDD prevention program (iodine fortification of salt) in an open population with current demographic characteristics in Germany and with moderate ID. We collected data on the prevalence, incidence, mortality, and quality of life from European studies for all health states of the model. Our primary net-benefit outcome was quality-adjusted life years (QALYs) predicted over a period of 120 years. In addition, we calculated incremental life years and disease events over time. We performed a systematic and comprehensive uncertainty assessment using multiple deterministic one-way sensitivity analyses. Results: In the base-case analysis, the IDD prevention program is more beneficial than no prevention, both in terms of QALYs and life years. Health gains predicted for the open cohort over a time horizon of 120 years for the German population (82.2 million inhabitants) were 33 million QALYs and 5 million life years. Nevertheless, prevention is not beneficial for all individuals since it causes additional hyperthyroidism (2.7 million additional cases). Results for QALY gains were stable in sensitivity analyses. Conclusions: IDD prevention via mandatory iodine fortification of salt increases quality-adjusted life expectancy in a European population with moderate ID, and is therefore beneficial on a population level. However, further ethical aspects should be considered before implementing a mandatory IDD prevention program. Costs for IDD prevention and treatment should be determined to evaluate the cost effectiveness of IDD prevention.

Barriers Against Prevention Programs for Iodine Deficiency Disorders in Europe: A Delphi Study.

Background: Although substantial progress has been made in recent decades in eliminating iodine deficiency, iodine deficiency disorders (IDDs) are still prevalent in European countries. Challenges include ineffective public health programs and discontinuation of IDD prevention. However, the barriers against the implementation and continuation of prevention and monitoring of IDD remain unclear. Therefore, the objective of our study was to identify potential barriers against pan-European IDD prevention and monitoring programs and to find solutions for the different challenges. Methods: We conducted a Delphi study consisting of three rounds. We identified potential participants with expertise and experience in relevant fields from all European countries, including policy makers, health care professionals, health scientists, and patient representatives. The Delphi method was conducted with open-ended questions and item ranking to achieve group consensus on potential barriers against national and pan-European IDD prevention and monitoring programs and related solutions to overcome those barriers. The answers of the Delphi rounds were analyzed using qualitative content analysis and descriptive analysis methods. In addition, we conducted two expert interviews to analyze and discuss the study results. Results: Eighty experts from 36 countries and different fields of work participated in the first Delphi round, 52 in the second, and 46 in the third. Potential barriers include challenges in the fields of knowledge and information, implementation and management, communication and cooperation, political support, and differences between the European countries. Ranked solutions addressing these barriers include cooperation with different stakeholders, gaining knowledge, sharing information, the development of a European program with national specification, European guidelines/recommendations, and European monitoring. The ranking gives a first overview as to which of these barriers would need to be solved most urgently and which solutions may be most helpful. Conclusion: In our study, we derived key information and first insights with regard to barriers against IDD prevention programs from a broad range of stakeholders. Most barriers were found in the category of implementation and management. Also a lack of political support seems to play an important role. The findings of our study may help decision makers in health policy to develop more effective IDD prevention and monitoring strategies.

Comparison of Various Methods to Determine Added Sugars Intake to Assess the Association of Added Sugars Intake and Micronutrient Adequacy.

Different methods for determining the effect of added sugars intake among children and adults on meeting recommended nutrient intakes were compared using 24 h dietary recall data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Four methods were used to determine deciles of added sugars intake (as the percentage of total calories): 1 day intake, 2 day average intake, and individual usual intake (UI) determined with the National Cancer Institute (NCI) and the multivariate Markov Chain Monte Carlo methods. Percentages of the population below the Estimated Average Requirement (EAR) for calcium and vitamin D/above the Adequate Intake (AI) for potassium and dietary fiber for each decile of added sugars intake were assessed with the NCI method. Using regression analyses, added sugars intake deciles (by any method) in children were inversely associated (p < 0.001) with percentages below the EAR/above the AI of vitamin D, calcium, potassium, and fiber. In adults, added sugars intake deciles were inversely associated with meeting recommendations for vitamin D, potassium, and fiber. There were no significant between-method differences for regression coefficients for any nutrients investigated. Overall, these methods showed a similar association of added sugars intake with nutrient inadequacy/adequacy; therefore, method preference may depend more on practical reasons.

Measuring socioeconomic gaps in nutrition and early child development in Bolivia.

BACKGROUND: A large body of evidence shows that socioeconomic status (SES) is strongly associated to children's early development, health and nutrition. Few studies have looked at within sample differences across multiple measures of child nutrition and development. This paper examines SES gaps in child nutritional status and development in Bolivia using a representative sample of children 0-59 months old and a rich set of outcomes, including micronutrient deficiencies, anthropometic measures, and gross motor and communicative development. METHODS: We construct direct and proxy measures of living standards based on household expenditures and on ownership of assets combined with access to services and dwelling characteristics. The data for this study come from a nationally representative household survey in Bolivia that contains information on health, nutrition, and child development tests. We used a regression framework to assess the adjusted associations between child development outcomes and socioeconomic status, after controlling for other demographic factors that might affect child's development. The SES gap in child development was estimated by OLS. To explore when the development gaps between children in different socioeconomic groups start and how they change for children at different ages, we analyze the differences in outcomes between the poorest (Q1) and richest (Q5) quintiles by child's age by estimating kernel weighted local polynomial regressions of standardized scores for all child development indicators. RESULTS: There are large and statistically significant differences in all anthropometrics z-scores between children in Q5 and children in Q1: height for age (0.95 SD), weight for age (0.70 SD), and weight for height (0.21 SD). When we divide the sample into children at the bottom and top consumption quintiles the results show that 68.6% of children in the poorest quintile are anemic. While this percentage falls to 40.9% for children in the richest quintile, it remains high compared to other countries in the region. The prevalence of vitamin A deficiency is 29.9% for children in the richest quintile and almost 10 percentage points higher for those at the bottom quintile (39.0%); the prevalence of Iron deficiency for children in the top and bottom quintiles is 16.4% and 23.8%, respectively. Compared to the most deprived quintile, children in the wealthiest quintile are less likely to have iron deficiency, anemia, to be stunted, and to have a risk of delays in gross motor and communicative development. At age three, most of these gaps have increased substantially. Our findings are robust to the choice of socioeconomic measurement and highlight the need for targeted policies to reduce developmental gaps. CONCLUSION: These findings highlight the need for targeted public policies that invest in multiple dimensions of child development as early as possible, including health, nutrition and cognitive and verbal stimulation. From a policy perspective, the large socioeconomic gaps in nutrition outcomes documented here reinforce the need to strengthen efforts that tackle the multiple causes of malnutrition for the poorest.

Role of Supplemental Nutrition Assistance Program in Improving Diet Quality: Implications for Nurses.

The Supplemental Nutrition Assistance Program (SNAP) provides access to healthy food for low-income individuals and households. Food security, however, does not necessarily achieve higher diet quality for beneficiaries. Diet quality is an important consideration for the development and management of chronic illness, a significant public health concern. In this study, we review incentives and disincentives implemented to improve the diet quality, the evidence on SNAP including benefits, challenges, and the politics of funding. New interventions and policies will be needed in order to improve the overall diet quality of SNAP households. SNAP should align with nutritional science to meet national public health goals. Nurses are trusted advocates for patients and the public and are uniquely positioned to aid in this effort. Informed by evidence, nurses willing to leverage their influence, can lead this needed change.

Estimating the Health and Economic Benefits of Universal Salt Iodization Programs to Correct Iodine Deficiency Disorders.

Background: There has been tremendous progress over the past 25 years to control iodine deficiency disorders (IDDs) through universal salt iodization (USI). In 2019, using the median urinary iodine concentration (MUIC), only 19 countries in the world are classified as iodine deficient; in contrast in 1993, using the total goiter rate (TGR), 113 countries were classified as iodine deficient. However, few analyses have tried to quantify the global health and economic benefits of USI programs, and the shift from TGR to MUIC as the main indicator of IDDs complicates assessment of progress. Methods: We used a novel approach to estimate the impact of USI on IDDs, applying a regression model derived from observational data on the relationship between the TGR and the MUIC from 24 countries. The model was used to generate hypothetical national TGR values for 2019 based on current MUIC data. TGR in 1993 and modeled TGR in 2019 were then compared for 139 countries, and using consequence modeling, the potential health and economic benefits realized between 1993 and 2019 were estimated. Results: Based on this approach, the global prevalence of clinical IDDs (as assessed by the TGR) fell from 13.1% to 3.2%, and 720 million cases of clinical IDDs have been prevented by USI (a reduction of 75.9%). USI has significantly reduced the number of newborns affected by IDDs, with 20.5 million cases prevented annually. The resulting improvement in cognitive development and future earnings suggest a potential global economic benefit of nearly $33 billion. However, 4.8 million newborns will be affected by IDDs in 2019, who will experience life-long productivity losses totaling a net present value of $12.5 billion. Conclusions: The global improvements in iodine status over the past 25 years have resulted in major health and economic benefits, mainly in low- and middle-income countries. Efforts should now focus on sustaining this achievement and expanding USI to reach the continuing large number of infants who remain unprotected from IDDs.

The Results of 16 Years of Iodization: Assessment of Iodine Deficiency Among School-age Children in Antalya, Turkey

Objective: Iodine deficiency (ID) continues to be a problem around the world. This study investigated the prevalence of ID and goiter among school-age children in the city center of Antalya, Turkey. The aim was to investigate the effect of an iodization program, which had been running for sixteen years, on nutritional iodine status in this population. Methods: A total of 1,594 school children, aged 6-14 years, were included in this cross-sectional study. ID was evaluated based on median [interquartile range (IQR)] urine iodine/creatine (UI/Cr) (µg/g) ratio and median (IQR) UI concentrations (UIC) (µg/L). UICs were measured using the Sandell-Kolthoff method. Goiter was determined by palpation and staged according to World Health Organization classification. Results: Median (IQR) UIC was found to be 174.69 (119.17-242.83) µg/L, and UIC was found to be lower than 50 µg/L in 6.5% of the population. The median UI/Cr ratio increased from 62.3 to 163.3 µg/g and goiter rates had decreased from 34% to 0.3% over the 16 years of the program. However, 19% were still classified as ID (mild, moderate or severe) and, furthermore, 11.5% were classified as excessive iodine intake. Conclusion: Comparison of two cross-sectional studies, carried out 16-years apart, showed that Antalya is no longer an ID region. However, surveillance should be continued and the percentage of ID and iodine excess individuals in the population should be monitored to avoid emerging problems.

Nutritional Deficiencies in Patients with Severe Obesity before Bariatric Surgery: What Should Be the Focus During the Preoperative Assessment?

BACKGROUND: Nutritional deficiencies are a well-recognized long-term complication following bariatric surgery. The presence of preoperative deficiencies has been shown to be predictive of postoperative deficiencies. OBJECTIVE: The aim of the study was to investigate the prevalence of micronutrient deficiency in a large sample of patients with severe obesity preoperatively, and to determine whether such deficiencies may be related to patient's sex, body mass index, or ethnic subgroup. DESIGN: A cross-sectional study of data collected at the time of the preoperative evaluation. PARTICIPANTS/SETTING: Data were collected during the preoperative evaluation of 872 bariatric surgery candidates in a university hospital in Israel between 2011 and 2018. The patients were 72.9% women, with a mean age of 37.9±12.1 years and mean body mass index of 42.4±4.7 MAIN OUTCOME MEASURES: Nutritional deficiencies according to blood assays. Data on anthropometrics, comorbidities, and demographic characteristics was also collected. STATISTICAL ANALYSES: Baseline differences between patient subgroups were analyzed using independent-samples t test, analysis of variance, or χ2 test. RESULTS: Deficiencies of vitamin D, iron, folate, vitamin B-12, elevated parathyroid hormone and low transferrin saturation were present in 75.2%, 42.6%, 28.5%, 8.5%, 35.5%, and 70% of patients, respectively. Nutritional deficiencies were significantly more common among women compared with men for iron (45.9% vs 33.5%; P=0.002), low transferrin saturation (77.7% vs 44.6%; P<0.001), vitamin D (77.5% vs 69.2%; P=0.019) and elevated parathyroid hormone level (39.5% vs 22.9%; P=0.002). Iron, transferrin saturation, and vitamin D deficiencies were more prevalent in Arab patients compared with Jewish patients: 59.6% vs 36%; P<0.001, 80.2% vs 62.8%; P=0.003, and 85.1% vs 71.6%; P<0.001, respectively. Vitamin D and iron deficiency were more common among higher body mass index subgroups (P=0.004 and P=0.040, respectively). CONCLUSIONS: The results indicate a high prevalence of nutritional deficiencies, mainly of iron and vitamin D in bariatric surgery candidates. Patients at higher risk for nutritional deficiencies include those with higher body mass index, women, and Arabs.

Impact of Nutritional Deficiencies on Children and Young Adults with Crohn's Disease Undergoing Intraabdominal Surgery.

PURPOSE: We examined the impact of comorbidities on length of stay and total hospital charges for children and young adults with Crohn's Disease (CD) undergoing surgery. METHODS: Patients (<21 years) were identified with a diagnosis of CD and an intraabdominal surgery in the Kids' Inpatient Database for the years 2006, 2009 and 2012. Length of stay (LOS) and total hospital charges (THC; USD$) were stratified by anemia, anxiety, depression and nutritional deficiency. National estimates were obtained using case weighting and multivariable linear regression was performed. RESULTS: We identified 3224 CD admissions with an intraabdominal surgery. The population was predominantly male, non-Hispanic white, and high school aged. There was an increase in LOS and THC for nutritional deficiency in all study years, and for depression and anemia in specific years. Multivariable linear regression revealed a 3.3-5.5 day increase in LOS associated with a comorbid diagnosis of nutritional deficiency. However, no increase in THC was seen for any comorbidity under evaluation. CONCLUSIONS: Behavioral health and, particularly, nutritional status have a significant impact on the care of children and young adults with CD. Nutritional deficiency, anemia, and depression resulted in increased LOS for those undergoing surgery. Improved presurgical management of comorbidities may reduce LOS for these patients. LEVEL OF EVIDENCE: III.

Endemic diseases of geochemical origin and methodological approaches toward their prevention and elimination.

A new approach to the study of diseases of geochemical origin is presented, which is based on the hypothesis that all such geochemical endemias were not possible in conditions of virgin biosphere and are products of human civilization. Two genetically different types of endemic diseases of geochemical origin are distinguished, each having a specifically spatial structure: (1) diseases of natural origin due to natural element deficiency or excess in the particular zones or areas; (2) diseases of anthropogenic origin related to chemical transformation of the environment in the course of agricultural or industrial production. Anthropogenically provoked diseases of geochemical nature always occur in conditions of already formed natural geochemical heterogeneity. As each type of the endemic disease has a peculiar structure of spatial distribution, the present health risk can be mapped as a genetically two-layer structure, characterizing deviation of the existing geochemical conditions from those ideal for specific species. Parameters of geochemical conditions, which are ideal for humans and domesticated species, should be sought within the areas with undisturbed soil cover, where these species have been formed in their present form. The hypothesis is tested on example of thyroid diseases observed in iodine-deficient areas affected by a nuclear accident with 131I fallout. The developed approach is believed to serve as a practical tool for monitoring and prevention of endemic diseases of geochemical origin.

Optimal Assessment and Quantification of Iodine Nutrition in Pregnancy and Lactation: Laboratory and Clinical Methods, Controversies and Future Directions.

Iodine intake must be boosted during pregnancy to meet the demands for increased production and placental transfer of thyroid hormone essential for optimal foetal development. Failure to meet this challenge results in irreversible brain damage, manifested in severity from neurological cretinism to minor or subtle deficits of intelligence and behavioural disorders. Attention is now being focused on explaining observational studies of an association between insufficient iodine intake during pregnancy and mild degrees of intellectual impairment in the offspring and confirming a cause and effect relationship with impaired maternal thyroid function. The current qualitative categorisation of iodine deficiency into mild, moderate and severe by the measurement of the median urinary iodine concentration (MUIC) in a population of school-age children, as a proxy measure of dietary iodine intake, is inappropriate for defining the degree or severity of gestational iodine deficiency and needs to be replaced. This review examines progress in analytical techniques for the measurement of urinary iodine concentration and the application of this technology to epidemiological studies of iodine deficiency with a focus on gestational iodine deficiency. We recommend that more precise definitions and measurements of gestational iodine deficiency, beyond a spot UIC, need to be developed. We review the evidence for hypothyroxinaemia as the cause of intrauterine foetal brain damage in gestational iodine deficiency and discuss the many unanswered questions, from which we propose that further clinical studies need to be designed to address the pathogenesis of neurodevelopmental impairments in the foetus and infant. Agreement on the testing instruments and standardization of processes and procedures for Intelligence Quotient (IQ) and psychomotor tests needs to be reached by investigators, so that valid comparisons can be made among studies of gestational iodine deficiency and neurocognitive outcomes. Finally, the timing, safety and the efficacy of prophylactic iodine supplementation for pregnant and lactating women needs to be established and confirmation that excess intake of iodine during pregnancy is to be avoided.

Food-basket intervention to reduce micronutrient deficiencies among Maasai-pregnant women in Tanzania: a quasi-experimental study.

BACKGROUND: Micronutrients comprised of vitamin and mineral nutrients that are needed during pregnancy for foetal growth, development and maturation, as well as for reducing/preventing maternal complications. However, micronutrient-rich foods (vegetables and fruits) are lacking in the Ngorongoro Conservation Area as a result of restrictions on cultivation in conservation areas and the unavailability of vegetables and fruits in local markets. The present study introduced a food basket intervention and assessed the effectiveness of the food baskets with respect to addressing anaemia, vitamin A and iron deficiencies among pregnant Maasai women within the Ngorongoro Conservation Area. METHODS: The quasi-experimental study included Misigiyo ward as a control group (provided education only) and Olbalbal ward as an intervention group (provided food baskets and education). The study assessed haemoglobin, serum ferritin and retinol at baseline and during follow-up. Haemoglobin, serum ferritin and retinol were quantitatively (duplicate) measured with HemoCue™ (HemoCue AB, Ängelholm, Sweden), Maglumi 800 (Snibe Diagnostic, Shenzhen, China) and vitamin A enzyme-linked immunosorbent assay, respectively. Dependent and independent t-tests were used to compare the micronutrient blood levels between and within the groups. RESULTS: The present study found a statistically significant increase in serum retinol (P < 0.001) in the intervention group compared to the control group; moreover, baseline serum retinol was positively associated with the follow-up serum retinol, whereas baseline haemoglobin and serum ferritin were negatively associated. CONCLUSIONS: The food basket intervention holds promise with repect to reducing micronutrient deficiency, especially in communities where micronutrient-rich foods are scarce.

Approaches to improving micronutrient status assessment at the population level.

Optimising micronutrient status globally is a major health priority. Nutritional biomarkers are critical for the identification of nutrient inadequacies in light of the limitations of dietary assessment methods. Early diagnosis and prevention of nutrient inadequacies require sensitive, validated and harmonised methods to determine and monitor micronutrient status in individual healthcare and population-based surveys. Important criteria in the identification, validation and implementation of nutritional biomarkers include the testing of biomarker specificity and sensitivity, and their response to dietary as well as physiologic changes, e.g. age or pregnancy. Nutritional status can be categorised into deficient, suboptimal, adequate and excess status, where appropriate, and provided cut-offs are available. Cut-offs are quantitative measures to reflect health outcomes and are important in validating nutritional surveys, interventions and monitoring of populations. For many biomarkers, available cut-offs have limited interpretability and are most commonly derived in adult populations only. For the comparison of studies from across the globe, the harmonisation of analytical methods is essential and can be realised with the use of internationally available reference material and interlaboratory comparison studies. This narrative review describes current efforts on identifying and validating existing and new biomarkers, the derivation of biomarker cut-offs, and international efforts on harmonisation of laboratory methods for biomarker quantitation and their interpretation, in the example of B-vitamins. Establishing sensitive, reliable and cost-efficient biomarkers and related cut-offs for use in populations across the globe are critical to facilitating the early diagnosis of micronutrient inadequacies on the clinical and community-based level for timely intervention and disease prevention.

Evidence on point-of-care diagnostics for assessment of nutritional biochemical markers as an integral part of maternal services in low- and middle-income countries: systematic scoping review protocol.

BACKGROUND: Malnutrition affects a third of the global population with low- and middle-income countries (LMICs) being the most affected. Most of those affected by malnutrition have limited means of determining their nutritional status. Recent developments of point-of-care (POC) diagnostics promise to enable early diagnosis of nutritional deficiencies or disease risk through biochemical indicator assessment. This provides potential opportunities for relatively simple interventions before the emergence of clinical symptoms. The main objective of this systematic scoping review is to map evidence on accessibility to POC diagnostic tests for the assessment of nutritional biochemical markers as an integral part of maternal health services in LMICs. METHODS AND ANALYSIS: We will search for relevant literature from the following databases: PubMed, Science Direct, EBSCOhost (Academic search complete, CINAHL with full text, MEDLINE with full text, MEDLINE), Google Scholar and World Health Organization library database. We will also search reference lists of included studies and existing networks such as organisations and conferences to source relevant literature. Primary research articles, published in peer-reviewed journals; review articles and grey literature that address the research question will be included. We will also search clinical trial registers to find relevant studies. Two independent reviewers will screen abstracts and full articles in parallel, from the included studies, using specific inclusion and exclusion criteria. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines will be used for reporting the screening results. NVivo version 10 will be employed to enable content thematic analysis of the review findings. A narrative summary of the results will be presented according to the emerging themes. DISCUSSION: We anticipate finding relevant literature on point-of-care diagnostic services for assessment of biochemical indicators as part of maternal services in low- and middle-income countries. The evidence obtained from the included studies when summarised will help to guide future research.