The cost-effectiveness of small-quantity lipid-based nutrient supplements for prevention of child death and malnutrition and promotion of healthy development: modelling results for Uganda.

OBJECTIVE: Recent meta-analyses demonstrate that small-quantity lipid-based nutrient supplements (SQ-LNS) for young children significantly reduce child mortality, stunting, wasting, anaemia and adverse developmental outcomes. Cost considerations should inform policy decisions. We developed a modelling framework to estimate the cost and cost-effectiveness of SQ-LNS and applied the framework in the context of rural Uganda. DESIGN: We adapted costs from a costing study of micronutrient powder (MNP) in Uganda, and based effectiveness estimates on recent meta-analyses and Uganda-specific estimates of baseline mortality and the prevalence of stunting, wasting, anaemia and developmental disability. SETTING: Rural Uganda. PARTICIPANTS: Not applicable. RESULTS: Providing SQ-LNS daily to all children in rural Uganda (> 1 million) for 12 months (from 6 to 18 months of age) via the existing Village Health Team system would cost ∼$52 per child (2020 US dollars) or ∼$58·7 million annually. SQ-LNS could avert an average of > 242 000 disability-adjusted life years (DALYs) annually as a result of preventing 3689 deaths, > 160 000 cases of moderate or severe anaemia and ∼6000 cases of developmental disability. The estimated cost per DALY averted is $242. CONCLUSIONS: In this context, SQ-LNS may be more cost-effective than other options such as MNP or the provision of complementary food, although the total cost for a programme including all age-eligible children would be high. Strategies to reduce costs, such as targeting to the most vulnerable populations and the elimination of taxes on SQ-LNS, may enhance financial feasibility.

Comparing two simplified questionnaire-based methods with 24-h recalls for estimating fortifiable wheat flour and oil consumption in Mandaluyong City, Philippines.

Information on fortifiable food consumption is essential to design, monitor and evaluate fortification programmes, yet detailed methods like 24-h recalls (24HRs) that provide such data are rarely conducted. Simplified questionnaire-based methods exist but their validity compared with 24HRs has not been shown. We compared two simplified methods (i.e., a household food acquisition and purchase questionnaire [FAPQ] and a 7-day semiquantitative food frequency questionnaire [SQ-FFQ]) against 24HRs for estimating fortifiable food consumption. We assessed the consumption of fortifiable wheat flour and oil using a FAPQ and, for wheat flour only, a 7-day SQ-FFQ and compared the results against 24HRs. The participants included children 12-18 months (n = 123) and their mothers 18-49 years selected for a study assessing child vitamin A intake and status in Mandaluyong City, Philippines. For fortifiable wheat flour, the FAPQ estimated considerably lower mean intakes compared to 24HRs for children and mothers (2.2 vs. 14.1 g/day and 5.1 vs. 42.3 g/day, respectively), while the SQ-FFQ estimated slightly higher mean intakes (15.7 vs. 14.1 g/day and 51.5 vs. 42.3 g/day, respectively). For fortifiable oil, the FAPQ estimated considerably higher mean intakes compared to 24HRs for children and mothers (4.6 vs. 1.8 g/day and 12.5 vs. 6.1 g/day, respectively). The SQ-FFQ, but not the FAPQ, generated useful information on fortifiable food consumption that can inform fortification programme design and monitoring decisions in the absence of more detailed individual-level data. Potential adaptations to improve the FAPQ, such as additional questions on foods prepared away from home and usage patterns, merit further research.

Advanced Dietary Analysis and Modeling: A Deep Dive into the National Cancer Institute Method.

BACKGROUND: The National Cancer Institute (NCI) method has been used widely by researchers to make inferences about usual dietary intake distributions of foods and nutrients based on a limited number of 24-h dietary recalls (24-HRs). Although the NCI method does not provide individual estimates of usual intake, it can be used to address many research questions, including modeling effects of nutrition interventions on population distributions of usual intake. Software for implementing the NCI method, and corresponding code examples, is publicly available in the form of SAS macros but little formal guidance exists for conducting advanced analyses. OBJECTIVES: We aim to present advanced techniques for working with NCI macros to conduct both basic and advanced dietary analyses and modeling. METHOD: We first present the 3 basic building blocks of analyses using the NCI method: 1) data set preparation, 2) application of the MIXTRAN macro to estimate parameters of the usual intake distribution, including effects of covariates, after transformation of 24-HRs to approximate normality, and 3) application of the DISTRIB macro to estimate the distribution of usual nutrient intake. Then, we illustrate how researchers can employ these building blocks to answer questions beyond typical descriptive analyses. RESULTS: Researchers can adapt the building blocks to: 1) account for factors such as demographic changes or nutrition interventions such as food fortification, 2) estimate the prevalence of dietary inadequacy via the full probability method, 3) incorporate nutrient intake from sources not always captured by 24-HRs, such as dietary supplements and human milk, and 4) carry out multiple subgroup analyses. This article describes the theoretical basis and operational guidance for these techniques. CONCLUSION: With this article as a detailed resource, researchers can leverage the basic NCI building blocks to investigate a wide range of questions about usual dietary intake distribution.

Introduction to the SIMPLE Macro, a Tool to Increase the Accessibility of 24-Hour Dietary Recall Analysis and Modeling.

BACKGROUND: Information on long-term dietary intake is often required for research or program planning, but surveys routinely use short-term assessments such as 24-h recalls (24HRs). Methods to reduce the impact of within-person variation in 24HRs, such as the National Cancer Institute (NCI) method, typically require extensive training and skill. OBJECTIVES: We introduce the Simulating Intake of Micronutrients for Policy Learning and Engagement (SIMPLE) macro, a new tool to increase the accessibility of 24HR analysis. We explain the underlying theory behind the tool and provide examples of potential applications. METHODS: The SIMPLE macro connects the core NCI statistical code to estimate usual intake distributions and includes additional code to enable advanced analyses such as predictive modeling. The related SIMPLE-Iron macro applies the full probability method to estimate inadequate iron intake, and the SIMPLE-1D macro is used for descriptive or modeling analyses of data with a single 24HR per person. The macros and associated documentations are freely available. We analyzed data from the US National Health and Nutrition Examination Survey (NHANES) and the Cameroon National Micronutrient Survey to compare the SIMPLE macro to 1) the core NCI code using the Estimated Average Requirement cut point method, and 2) the IMAPP software for iron only, and to demonstrate the applications of the SIMPLE macro for estimating usual intake and predictive modeling. RESULTS: The SIMPLE macro generates identical results to the core NCI code. The SIMPLE-Iron macro also produces estimates of inadequate iron intake comparable to the IMAPP software. The examples demonstrate application of the SIMPLE macro to 1) descriptive analyses of nutrient intake from food and supplements (NHANES), and 2) analyses accounting for breast-milk nutrient intake and modeling fortification and supplementation programs (Cameroon). CONCLUSIONS: The SIMPLE macros may facilitate the analysis and modeling of dietary data to inform nutrition research, programs, and policy.

Determination of Vitamin A Total Body Stores in Children from Dried Serum Spots: Application in a Low- and Middle-Income Country Community Setting.

BACKGROUND: The retinol isotope dilution (RID) method has been used to evaluate vitamin A (VA) status in healthy adults and children in low- and middle-income countries (LMIC) and to assess the efficacy of various VA interventions. OBJECTIVE: The study was designed to examine whether dried serum spots (DSS) can be applied to RID when conducting VA total body store (TBS) assessments in community settings. METHODS: Four days after an oral dose of 0.4 mg [13C10]retinyl acetate was administered to Filipino children (12-18 mo), a single blood draw was divided to isolate both serum and plasma. Serum (40 µL) was spotted and dried on Whatman 903 cards and shipped at ambient temperature whereas liquid plasma (LP) was frozen at -80°C and shipped on dry ice. The VA tracer to tracee ratio from DSS and LP was quantified by LC-MS/MS. Comparisons between DSS and LP paired samples (n = 72) were made for [13C10]retinol specific activity (SAp) by Pearson's correlation and for VA TBS by Bland-Altman analysis. RESULTS: The sum of 3 coextracted DSS were required to consistently detect [13C10]retinol above the LC-MS/MS limit of quantitation (LOQ). [13C10]retinol SAp from DSS was highly correlated with SAp from LP (r = 0.945; P < 0.01). A comparison of methods for TBS determination using Bland-Altman analysis indicated agreement with an intraindividual difference of 24.7 µmol (4.6%). Mean total liver reserve (TLR) values from DSS and LP were 1.7 µmol/g (± 0.6 SD) and 1.6 µmol/g (± 0.6 SD), respectively. CONCLUSIONS: VA TBS can be determined from DSS thereby reducing the logistics and cost of maintaining a cold chain by shipping samples at ambient temperature and, thus, making the RID technique more feasible in LMIC community settings. This trial was registered at https://clinicaltrials.gov as NCT03030339.

Use of Model-Based Compartmental Analysis and a Super-Child Design to Study Whole-Body Retinol Kinetics and Vitamin A Total Body Stores in Children from 3 Lower-Income Countries.

BACKGROUND: Model-based compartmental analysis has been used to describe and quantify whole-body vitamin A metabolism and estimate total body stores (TBS) in animals and humans. OBJECTIVES: We applied compartmental modeling and a super-child design to estimate retinol kinetic parameters and TBS for young children in Bangladesh, Guatemala, and the Philippines. METHODS: Children ingested [13C10]retinyl acetate and 1 or 2 blood samples were collected from each child from 6 h to 28 d after dosing. Temporal data for fraction of dose in plasma [13C10]retinol were modeled using WinSAAM software and a 6-component model with vitamin A intake included as weighted data. RESULTS: Model-predicted TBS was 198, 533, and 1062 µmol for the Bangladeshi (age, 9-17 mo), Filipino (12-18 mo), and Guatemalan children (35-65 mo). Retinol kinetics were similar for Filipino and Guatemalan groups and generally faster for Bangladeshi children, although fractional transfer of plasma retinol to a larger exchangeable storage pool was the same for the 3 groups. Recycling to plasma from that pool was ∼2.5 times faster in the Bangladeshi children compared with the other groups and the recycling number was 2-3 times greater. Differences in kinetics between groups are likely related to differences in vitamin A stores and intakes (geometric means: 352, 727, and 764 µg retinol activity equivalents/d for the Bangladeshi, Filipino, and Guatemalan children, respectively). CONCLUSIONS: By collecting 1 or 2 blood samples from each child to generate a composite plasma tracer data set with a minimum of 5 children/time, group TBS and retinol kinetics can be estimated in children by compartmental analysis; inclusion of vitamin A intake data increases confidence in model predictions. The super-child modeling approach is an effective technique for comparing vitamin A status among children from different populations. These trials were registered at www.clinicaltrials.gov as NCT03000543 (Bangladesh), NCT03345147 (Guatemala), and NCT03030339 (Philippines).

A New Statistical Method for Estimating Usual Intakes of Nearly-Daily Consumed Foods and Nutrients Through Use of Only One 24-hour Dietary Recall.

BACKGROUND: To estimate usual intake distributions of dietary components, collection of nonconsecutive repeated 24-h dietary recalls is recommended, but resource limitations sometimes restrict data collection to single-day dietary data per person. OBJECTIVES: We developed a new statistical method, the NCI 1-d method, which uses single-day dietary data and an external within-person to between-person variance ratio to estimate population distributions of usual intake of nearly-daily consumed foods and nutrients. METHODS: We used NHANES 2011-2014 data for men (n = 4938 and n = 4293 for the first and second 24-h recalls) to compare nutrient intake distributions of vitamin A, magnesium, folate, and vitamin E generated by the 1-d method (with use of only the first recall per person) with those from the NCI amount-only method (with use of all days of dietary intake per person). The within-person to between-person variance ratio from the amount-only model was used as the unbiased "external" estimate for the 1-d method. We also examined the effect of mis-specification of variance ratios on usual intake distributions. RESULTS: The amount-only and 1-d methods estimated statistically equivalent median (25p, 75p): 647 (459, 890) compared with 648 (461, 886) µg retinol activity equivalents/d, 338 (268, 420) compared with 334 (266, 417) mg magnesium/d, 595 (458, 762) compared with 589 (456, 758) µg dietary folate equivalents/d, and 9.7 (7.3, 12.6) compared with 9.6 (7.3, 12.7) mg vitamin E/d. As the external variance ratios increased from 25% to 200% of the unbiased ratios, the prevalence of inadequate intake ranged from 53% to 43% for vitamin A, 57% to 55% for magnesium, 16% to 2% for folate, and 70% to 73% for vitamin E. CONCLUSIONS: The 1-d method is a viable statistical method for estimating usual intakes of nearly-daily consumed dietary components when the variance ratio is unbiased. Results are sensitive to variance ratio selection, so researchers should still collect replicate data where possible.

Prevalence and predictors of overweight and obesity among Cameroonian women in a national survey and relationships with waist circumference and inflammation in Yaoundé and Douala.

Information on the distribution and predictors of obesity in Africa is needed to identify populations at risk and explore intervention options. Our objectives were to (a) examine the prevalence and geographic distribution of overweight and obesity among Cameroonian women; (b) evaluate change in anthropometric indicators among urban women between 2009 and 2012; (c) examine associations between household and individual characteristics and overweight and obesity; and (d) examine relationships between body mass index (BMI), abdominal obesity, and inflammation. We analysed data from a nationally representative survey conducted in 3 geographic strata (North, South, and Yaoundé/Douala) in Cameroon in 2009 and a survey in Yaoundé/Douala in 2012. Participants selected for this analysis were nonpregnant women, ages 15-49 years (n = 704 in 2009; n = 243 in 2012). In 2009, ~8% of women were underweight (BMI < 18.5) and 32% overweight or obese (BMI ≥ 25.0). Underweight was most common in the North (19%) and overweight and obesity in the South (40%) and Yaoundé/Douala (49%). Prevalence of BMI ≥ 25.0 in Yaoundé/Douala did not differ in 2012 compared with 2009 (55.5% vs. 48.7%; P = 0.16). Residence in urban areas, greater maternal age, and TV ownership were independently related to overweight and obesity in national and stratified analyses. In Yaoundé/Douala in 2012, 48% (waist-to-hip ratio > 0.85) to 73% (waist circumference > 80 cm) had abdominal obesity. Body mass index was positively associated with abdominal obesity and inflammation. Though causal inferences cannot be drawn, these findings indicate population subgroups at greatest risk for overweight and associated health consequences in Cameroon.

Estimating Lives Saved by Achieving Dietary Micronutrient Adequacy, with a Focus on Vitamin A Intervention Programs in Cameroon.

Background: We previously compared the potential effects of different intervention strategies for achieving dietary vitamin A (VA) adequacy. The Lives Saved Tool (LiST) permits estimates of lives saved through VA interventions but currently only considers periodic VA supplements (VASs).Objective: We aimed to adapt the LiST method for estimating the mortality impact of VASs to estimate the impact of other VA interventions (e.g., food fortification) on child mortality and to estimate the number of lives saved by VA interventions in 3 macroregions in Cameroon.Methods: We used national dietary intake data to predict the effects of VA intervention programs on the adequacy of VA intake. LiST parameters of population affected fraction and intervention coverage were replaced with estimates of prevalence of inadequate intake and effective coverage (proportion achieving adequate VA intake). We used a model of liver VA stores to derive an estimate of the mortality reduction from achieving dietary VA adequacy; this estimate and a conservative assumption of equivalent mortality reduction for VAS and VA intake were applied to projections for Cameroon.Results: There were 2217-3048 total estimated VA-preventable deaths in year 1, with 58% occurring in the North macroregion. The relation between effective coverage and lives saved differed by year and macroregion due to differences in total deaths, diarrhea burden, and prevalence of low VA intake. Estimates of lives saved by VASs (the intervention common to both methods) were similar with the use of the adapted method (in 2012: North, 743-1021; South, 280-385; Yaoundé and Douala, 146-202) and the "usual" LiST method (North: 697; South: 381; Yaoundé and Douala: 147).Conclusions: Linking effective coverage estimates with an adapted LiST method permits estimation of the effects of combinations of VA programs (beyond VASs only) on child mortality to aid program planning and management. Rigorous program monitoring and evaluation are necessary to confirm predicted impacts.

Iron, Zinc, Folate, and Vitamin B-12 Status Increased among Women and Children in Yaoundé and Douala, Cameroon, 1 Year after Introducing Fortified Wheat Flour.

Background: Few data are available on the effectiveness of large-scale food fortification programs.Objective: We assessed the impact of mandatory wheat flour fortification on micronutrient status in Yaoundé and Douala, Cameroon.Methods: We conducted representative surveys 2 y before and 1 y after the introduction of fortified wheat flour. In each survey, 10 households were selected within each of the same 30 clusters (n = ∼300 households). Indicators of inflammation, malaria, anemia, and micronutrient status [plasma ferritin, soluble transferrin receptor (sTfR), zinc, folate, and vitamin B-12] were assessed among women aged 15-49 y and children 12-59 mo of age.Results: Wheat flour was consumed in the past 7 d by ≥90% of participants. Postfortification, mean total iron and zinc concentrations of flour samples were 46.2 and 73.6 mg/kg (target added amounts were 60 and 95 mg/kg, respectively). Maternal anemia prevalence was significantly lower postfortification (46.7% compared with 39.1%; adjusted P = 0.01), but mean hemoglobin concentrations and child anemia prevalence did not differ. For both women and children postfortification, mean plasma concentrations were greater for ferritin and lower for sTfR after adjustments for potential confounders. Mean plasma zinc concentrations were greater postfortification and the prevalence of low plasma zinc concentration in women after fortification (21%) was lower than before fortification (39%, P < 0.001); likewise in children, the prevalence postfortification (28%) was lower than prefortification (47%, P < 0.001). Mean plasma total folate concentrations were ∼250% greater postfortification among women (47 compared with 15 nmol/L) and children (56 compared with 20 nmol/L), and the prevalence of low plasma folate values was <1% after fortification in both population subgroups. In a nonrepresentative subset of plasma samples, folic acid was detected in 77% of women (73% of those fasting) and 93% of children. Mean plasma and breast-milk vitamin B-12 concentrations were >50% greater postfortification.Conclusion: Although the pre-post survey design limits causal inference, iron, zinc, folate, and vitamin B-12 status increased among women and children in urban Cameroon after mandatory wheat flour fortification.

Dietary gap assessment: an approach for evaluating whether a country's food supply can support healthy diets at the population level.

OBJECTIVE: Dietary diversity, and in particular consumption of nutrient-rich foods including fruits, vegetables, nuts, beans and animal-source foods, is linked to greater nutrient adequacy. We developed a 'dietary gap assessment' to evaluate the degree to which a nation's food supply could support healthy diets at the population level. Design/Setting In the absence of global food-based dietary guidelines, we selected the Dietary Approaches to Stop Hypertension (DASH) diet as an example because there is evidence it prevents diet-related chronic disease and supports adequate micronutrient intakes. We used the DASH guidelines to shape a hypothetical 'healthy' diet for the test country of Cameroon. Food availability was estimated using FAO Food Balance Sheet data on country-level food supply. For each of the seven food groups in the 'healthy' diet, we calculated the difference between the estimated national supply (in kcal, edible portion only) and the target amounts. RESULTS: In Cameroon, dairy and other animal-source foods were not adequately available to meet healthy diet recommendations: the deficit was -365 kcal (-1527 kJ)/capita per d for dairy products and -185 kcal (-774 kJ)/capita per d for meat, poultry, fish and eggs. Adequacy of fruits and vegetables depended on food group categorization. When tubers and plantains were categorized as vegetables and fruits, respectively, supply nearly met recommendations. Categorizing tubers and plantains as starchy staples resulted in pronounced supply shortfalls: -109 kcal (-457 kJ)/capita per d for fruits and -94 kcal (-393 kJ)/capita per d for vegetables. CONCLUSIONS: The dietary gap assessment illustrates an approach for better understanding how food supply patterns need to change to achieve healthier dietary patterns.

Maximizing the benefits and minimizing the risks of intervention programs to address micronutrient malnutrition: symposium report.

Interventions to address micronutrient deficiencies have large potential to reduce the related disease and economic burden. However, the potential risks of excessive micronutrient intakes are often not well determined. During the Global Summit on Food Fortification, 9-11 September 2015, in Arusha, a symposium was organized on micronutrient risk-benefit assessments. Using case studies on folic acid, iodine and vitamin A, the presenters discussed how to maximize the benefits and minimize the risks of intervention programs to address micronutrient malnutrition. Pre-implementation assessment of dietary intake, and/or biomarkers of micronutrient exposure, status and morbidity/mortality is critical in identifying the population segments at risk of inadequate and excessive intake. Dietary intake models allow to predict the effect of micronutrient interventions and their combinations, e.g. fortified food and supplements, on the proportion of the population with intakes below adequate and above safe thresholds. Continuous monitoring of micronutrient intake and biomarkers is critical to identify whether the target population is actually reached, whether subgroups receive excessive amounts, and inform program adjustments. However, the relation between regular high intake and adverse health consequences is neither well understood for many micronutrients, nor do biomarkers exist that can detect them. More accurate and reliable biomarkers predictive of micronutrient exposure, status and function are needed to ensure effective and safe intake ranges for vulnerable population groups such as young children and pregnant women. Modelling tools that integrate information on program coverage, dietary intake distribution and biomarkers will further enable program makers to design effective, efficient and safe programs.

Regional, Socioeconomic, and Dietary Risk Factors for Vitamin B-12 Deficiency Differ from Those for Folate Deficiency in Cameroonian Women and Children.

BACKGROUND: Representative data on folate and vitamin B-12 dietary intake and status in low-income countries are rare, despite the widespread adoption of folic acid fortification. OBJECTIVE: The purpose of this study was to evaluate folate and vitamin B-12 intake, status, and risk factors for deficiency before implementation of a national fortification program in Cameroon. METHODS: A nationally representative cross-sectional cluster survey was conducted in 3 ecologic zones of Cameroon (South, North, and the 2 largest cities, Yaoundé/Douala), and information on dietary intake was collected from 10 households in each of 30 randomly selected clusters per zone. In a subset of women and their 12- to 59-mo-old children (n = 396 pairs), plasma folate and vitamin B-12, as well as breast milk vitamin B-12, were analyzed. RESULTS: Vitamin B-12 and folate dietary intake patterns and plasma concentrations were similar for women and children. In the subsample, 18% and 29% of women and 8% and 30% of children were vitamin B-12 (≤ 221 pmol/L) and folate (< 10 nmol/L) deficient, respectively. Mean dietary folate ranged from 351 µg dietary folate equivalents/d in the North to 246 µg dietary folate equivalents/d in Yaoundé/Douala; plasma folate was negatively associated with socioeconomic status (P = 0.001). Plasma vitamin B-12 deficiency was similar in the South and North, 29% and 40%, respectively, but was only 11% in Yaoundé/Douala, and was positively associated with socioeconomic status. Mean breast milk vitamin B-12 was statistically significantly lower in the North (101 pmol/L) than in the South (296 pmol/L) or Yaoundé/Douala (349 pmol/L). CONCLUSIONS: Folate intake and status are inadequate among women and young children in Yaoundé/Douala, whereas low vitamin B-12 intake and status are more common in poor and rural areas, especially in the North. Different strategies may be needed to control deficiency of these nutrients in different regions of Cameroon.

Comparison of a Household Consumption and Expenditures Survey with Nationally Representative Food Frequency Questionnaire and 24-hour Dietary Recall Data for Assessing Consumption of Fortifiable Foods by Women and Young Children in Cameroon.

BACKGROUND: Household Consumption and Expenditures Surveys (HCES) are potential sources of data on dietary patterns for planning fortification programs, but they rarely have been compared with individual-level dietary assessment methods. OBJECTIVE: To compare apparent consumption of fortifiable foods estimated from the Third Cameroon Household Survey (ECAM3) with the results of a national dietary survey using food frequency questionnaire (FFQ) and 24-hour recall (24HR) methods among women aged 15 to 49 years and children aged 12 to 59 months. METHODS: We estimated coverage and frequency of consumption in the previous week (ECAM3 and FFQ) and coverage and amount consumed on the previous day (ECAM3 and 24HR) of refined vegetable oil, wheat flour, sugar, and bouillon cubes. RESULTS: Coverage in the past week as measured by the ECAM3 and FFQ, respectively, was 64% vs. 54% for oil, 60% vs. 92% for flour, 69% vs. 78% for sugar, and 85% vs. 96% for bouillon cubes. The different methods identified similar patterns of coverage among subgroups for oil, but patterns for other foods were variable. Frequency of consumption and previous-day coverage were lower with the ECAM3 than with the FFQ and 24HR, likely reflecting infrequent acquisition relative to intake. For women, the mean amounts consumed on the previous day (among consumers) were 43 vs. 29 g of oil, 71 vs. 83 g of flour, 42 vs. 32 g of sugar, and 5.0 vs. 2.4 g of bouillon cubes (ECAM and 24HR, respectively). CONCLUSIONS: HCES provide useful information on patterns of food access but inadequate information on individual consumption amounts to estimate appropriate food fortification levels.

An Economic Optimization Model for Improving the Efficiency of Vitamin A Interventions: An Application to Young Children in Cameroon.

BACKGROUND: Vitamin A (VA) intervention programs in developing countries do not generally consider spatial differences in needs or in intervention costs. New data from Cameroon reveal nonuniform spatial distributions of VA deficiency among young children and of costs of some of the programs designed to address them. METHODS: We develop a spatially explicit, intertemporal economic optimization tool that makes use of subnational dietary intake data and VA intervention program costs to identify more efficient sets of interventions to improve VA nutrition among young children aged 6 to 59 months in Cameroon. RESULTS: The model suggests substantial changes in the composition and geographic foci of VA intervention programs vis-à-vis a business-as-usual scenario. National VA-fortified edible oil and bouillon cube programs are cost-effective, even when start-up costs are considered. High-dosage VA supplementation delivered via Child Health Days is most cost-effective in the North macro-region, where needs are greatest and the cost per child effectively covered is lowest. Overall, the VA intervention programs suggested by the optimization model are approximately 44% less expensive, with no change in the total number of children effectively covered nationwide. CONCLUSIONS: The VA intervention programs should consider spatial and temporal differences in needs and in the expected benefits and costs of alternative VA interventions. Doing so will require spatially disaggregated strategies and the data and political will to support them, longer planning time horizons than are currently used in most developing countries, and long-term funding commitments.

Use of Optimization Modeling for Selecting National Micronutrient Intervention Strategies: An Example Based on Potential Programs for Control of Vitamin A Deficiency in Cameroon.

Vitamin and mineral (micronutrient [MN]) deficiencies are common in lower income countries, especially among young children and women of reproductive age. These deficiencies are cause for serious concern because of their high prevalence and their associated complications, which include depressed immune function and increased risk and severity of infections, impaired neurocognitive development, and anemia, which together result in elevated mortality and reduced human productive capacity. A broad range of different intervention strategies are available to control MN deficiencies. At present, these interventions are usually implemented at a national scale through different public and private sector entities, often with little coordination. We have developed a set of models based on the estimated ability of different interventions to achieve effective coverage and the necessary financial resources required to deploy these interventions. The models provide a unified and transparent framework for considering different options using the common indicator of effective coverage. More specifically, information on nutritional benefits and costs are analyzed using an economic optimization model to identify the mix of interventions that could be delivered to specific target groups in particular geographic areas to achieve a desired level of effective coverage at lowest cost. Alternatively, these optimization models can be developed to identify the combination of interventions needed to achieve the maximum effective coverage, given specified budgetary limitations. The results of these models can be useful input into policy-making processes. To introduce this analytical approach, the set of papers in this volume addresses the problem of vitamin A deficiency among young children in Cameroon.

Estimating the Effective Coverage of Programs to Control Vitamin A Deficiency and Its Consequences Among Women and Young Children in Cameroon.

BACKGROUND: To compare the cost-effectiveness of nutrition programs, the anticipated nutritional benefits of each intervention must be expressed using a common metric. OBJECTIVE: We present the methodology for estimating the benefits of vitamin A (VA)-related interventions among women and children in Cameroon. METHODS: We estimated "reach" (proportion of the population that receives a program), "coverage" (proportion that is deficient and receives a program), and "effective coverage" (proportion that "converts" from inadequate to adequate VA intake following an intervention) using dietary data collected during a national survey in 3 macro-regions of Cameroon (North, South, and Yaoundé/Douala). Effective coverage of programs such as (bio)fortification and micronutrient powders was estimated by adding the dietary VA contributed by the intervention to baseline VA intakes, including the contribution of increased maternal VA intake to infant VA intake through increases in breast milk VA. For interventions that provide VA-related benefits through other pathways (eg, periodic high-dose VA supplements and deworming), we developed alternative methods of estimating "daily VA intake equivalents. " RESULTS: Baseline VA intakes and intervention reach varied by geographic macro-region. On average, estimates of program reach were greater than the effective coverage estimates by ∼50%. Effective coverage varied by intervention package and macro-region, ranging from <20 000 (deworming, Yaoundé/Douala) to >400 000 (micronutrient powder or VA supplement, North) children effectively covered per year. CONCLUSION: These estimates of effective coverage, along with macro-region-specific information on the costs of each intervention package, serve as inputs into an economic optimization model to identify the most cost-effective package of VA interventions for each macro-region of Cameroon.

Measuring the Costs of Vitamin A Interventions: Institutional, Spatial, and Temporal Issues in the Context of Cameroon.

BACKGROUND: To address vitamin A (VA) deficiency, an array of interventions have been developed for increasing VA status among young children. With numerous possible combinations of interventions, however, comes the need to take decisions regarding which intervention or combination of interventions is most cost effective for achieving VA deficiency reduction targets. METHODS: Detailed intervention-specific, "macro-region"-level data in Cameroon are used to generate estimates of the costs associated with delivering VA to children aged 6 to 59 months. RESULTS: In Cameroon, our estimates of costs per effectively-covered child (ie, children at risk of inadequate intake of VA who are exposed to an intervention and who achieve adequate intake) each year (2 rounds of Child Health Days [CHDs]) were US$3.31 for VA supplements. VA fortification of edible oil and bouillon cube was US$2.95 and US$2.41, respectively, per child effectively covered per year, and biofortification of maize was US$5.30 per child effectively covered per year. Combinations of interventions could reduce costs (eg, delivering additional interventions that affect VA status through the CHDs). Spatial differences in costs within Cameroon were also evident, for example, delivering high-dose VA capsules through CHDs leads to a cost of US$0.77 per child reached in the northern regions compared to US$1.40 per child reached in the southern regions. CONCLUSION: The costs associated with alternative VA interventions in Cameroon differ spatially, temporally, and in their cost-effectiveness. Choosing the appropriate combination of interventions can produce a more efficient portfolio of interventions to address VA deficiencies and VA-related deaths.

Simulations based on representative 24-h recall data predict region-specific differences in adequacy of vitamin A intake among Cameroonian women and young children following large-scale fortification of vegetable oil and other potential food vehicles.

BACKGROUND: The WHO recommends assessing food and nutrient intakes to design food-fortification programs, but nationally representative dietary data are seldom available in low-income countries. OBJECTIVE: Prior to initiation of food fortification in Cameroon, we measured intake of vitamin A (VA) and fortifiable foods (vegetable oil, sugar, wheat flour, and bouillon cube) to simulate the effects of fortification with different foods and VA amounts on prevalence of inadequate and excessive VA intake. METHODS: Twenty-four-hour recalls were conducted among 912 women and 883 children (with duplicates in a subset) in a nationally representative cluster survey stratified by region (North, South, Yaoundé/Douala). Usual intake distributions were estimated by the National Cancer Institute method. RESULTS: Nationally, 53% of women had a usual intake of <500 µg retinol activity equivalents/d, and 59% of nonbreastfeeding children had an intake of <210 µg retinol activity equivalents/d, although VA intake varied by region. The current fortification program (12 mg/kg VA in oil) would decrease the prevalence of inadequate intakes to 35% among both women and children, without increasing the proportion with retinol intakes >3000 µg/d among women or >600 µg/d among children. However, inadequate VA intake would remain >50% in the North, where VA deficiency was most common. Increasing VA in oil or fortifying a second food (sugar, wheat flour, or bouillon cube) would further decrease the prevalence of inadequate intakes, but, depending on the food vehicle and region, would also increase the prevalence of retinol intakes above the tolerable upper intake level, mainly among children. CONCLUSIONS: The current food-fortification program can be expected to improve dietary VA adequacy without increasing the risk of excessive intake among women and children in Cameroon. Modifications to the program must balance the potential to further increase VA intake with the risk of excessive intake among children.