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.

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.

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.

Impacts of micronutrient intervention programs on effective coverage and lives saved: Modeled evidence from Cameroon.

Policymakers are committed to improving nutritional status and to saving lives. Some micronutrient intervention programs (MIPs) can do both, but not to the same degrees. We apply the Micronutrient Intervention Modeling tool to compare sets of MIPs for (1) achieving dietary adequacy separately for zinc, vitamin A (VA), and folate for children and women of reproductive age (WRA), and (2) saving children's lives via combinations of MIPs. We used 24-h dietary recall data from Cameroon to estimate usual intake distributions of zinc and VA for children 6-59 months and of folate for WRA. We simulated the effects on dietary inadequacy and lives saved of four fortified foods and two VA supplementation (VAS) platforms. We estimated program costs over 10 years. To promote micronutrient-specific dietary adequacy, the economic optimization model (EOM) selected zinc- and folic acid-fortified wheat flour, VA-fortified edible oils, and bouillon cubes, and VAS via Child Health Days in the North macroregion. A different set of cost-effective MIPs emerged for reducing child mortality, shifting away from VA and toward more zinc for children and more folic acid for WRA. The EOM identified more efficient sets of MIPs than the business-as-usual MIPs, especially among programs aiming to save lives.

Comparing estimated cost-effectiveness of micronutrient intervention programs using primary and secondary data: evidence from Cameroon.

Designing a cost-effective portfolio of micronutrient intervention programs is complex and generally undertaken with limited data. We developed the MINIMOD-Secondary Data (MINIMOD-SD) tool, which uses household consumption and expenditure survey data and other secondary data to estimate apparent nutrient intakes and model the effectiveness and cost-effectiveness of micronutrient intervention programs. We present the SD tool methodology and results in the context of Cameroon, with a particular focus on vitamin A (VA) for children and folate for women of reproductive age (WRA). We compared the MINIMOD-SD tool estimates with those of the full MINIMOD tool, which uses 24-h dietary recall data. The SD tool consistently underestimated folate intake among women (median (IQR): 230 (143,352) versus 303 (244,367) µg dietary folate equivalents (DFEs)/day) and especially VA among children (141 (64,279) versus 227 (102,369)). Qualitatively, however, the two tools were generally consistent in predicted subnational patterns of micronutrient adequacy and identification of effective and cost-effective (cost per child/WRA moving from inadequate to adequate intake) interventions. Secondary data and the MINIMOD-SD tool can provide policymakers with information to qualitatively assess deficiency risks and identify cost-effective interventions. However, accurately quantifying individual-level deficiency or dietary inadequacy and intervention effectiveness and cost-effectiveness will likely require individual-level dietary data and biomarker measurements.

Predicted Effects and Cost-Effectiveness of Wheat Flour Fortification for Reducing Micronutrient Deficiencies, Maternal Anemia, and Neural Tube Defects in Yaoundé and Douala, Cameroon.

BACKGROUND: Policy makers aiming to reduce micronutrient deficiencies (MNDs) and their health effects must choose among alternative definitions of impact when evaluating cost-effectiveness. OBJECTIVE: Estimate the cost-effectiveness of a mandatory wheat flour fortification program for reducing cases of MNDs (iron, zinc, folate, vitamin B12), anemia and neural tube defects (NTDs) averted, and disability-adjusted life years (DALYs) averted in urban Cameroon. METHODS: A 13-year predictive model was developed, including a 3-year start-up period and 10 years of program activity. Costs were estimated using historical program budgets. Effects were calculated based on observed changes in prevalence of MND and anemia 1 year postfortification and predicted reductions in NTDs based on NTD burden and wheat flour intake. Total DALYs averted were estimated for anemia and NTDs. RESULTS: The program cost ∼$2.4 million over 13 years and averted an estimated ∼95 000 cases of maternal anemia and ∼83 500 cases of iron deficiency among children after 1 year. Cost/case-year averted for MNDs ranged from $0.50 for low plasma folate to $3.30 for iron deficiency and was $2.20 for maternal anemia. The program was predicted to avert 1600 cases of NTDs over 10 years at ∼$1500 per case averted. Estimated cost/DALY averted was $50 for NTDs and $115 for anemia. CONCLUSIONS: In Cameroon, cost-effectiveness of wheat flour fortification varied by the measure of impact employed, but was classified as "very cost-effective" for all outcomes using World Health Organization criteria. Policy makers and their advisors must determine how best to use information on program costs and benefits to inform their decisions.

Strategies to achieve adequate vitamin A intake for young children: options for Cameroon.

Meeting children's vitamin A (VA) needs remains a policy priority. Doing so efficiently is a fiscal imperative and protecting at-risk children during policy transitions is a moral imperative. Using the Micronutrient Intervention Modeling tool and data for Cameroon, we predict the impacts and costs of alternative VA intervention programs, identify the least-cost strategy for meeting targets nationally, and compare it to a business-as-usual (BAU) strategy over 10 years. BAU programs effectively cover ∼12.8 million (m) child-years (CY) and cost ∼$30.1 m; ∼US$2.34 per CY effectively covered. Improving the VA-fortified oil program, implementing a VA-fortified bouillon cube program, and periodic VA supplements (VAS) in the North macroregion for 3 years effectively cover ∼13.1 m CY at a cost of ∼US$9.5 m, or ∼US$0.71 per CY effectively covered. The tool then identifies a sequence of subnational policy choices leading from the BAU toward the more efficient strategy, while addressing VA-attributable mortality concerns. By year 4, fortification programs are predicted to eliminate inadequate VA intake in the South and Cities macroregions, but not the North, where VAS should continue until additional delivery platforms are implemented. This modeling approach offers a concrete example of the strategic use of data to follow the Global Alliance for VA framework and do so efficiently.

Weighing the risks of high intakes of selected micronutrients compared with the risks of deficiencies.

Several intervention strategies are available to reduce micronutrient deficiencies, but uncoordinated implementation of multiple interventions may result in excessive intakes. We reviewed relevant data collection instruments and available information on excessive intakes for selected micronutrients and considered possible approaches for weighing competing risks of intake above tolerable upper intake levels (ULs) versus insufficient intakes at the population level. In general, population-based surveys in low- and middle-income countries suggest that dietary intakes greater than the UL are uncommon, but simulations indicate that fortification and supplementation programs could lead to high intakes under certain scenarios. The risk of excessive intakes can be reduced by considering baseline information on dietary intakes and voluntary supplement use and continuously monitoring program coverage. We describe a framework for comparing risks of micronutrient deficiency and excess, recognizing that critical information for judging these risks is often unavailable. We recommend (1) assessing total dietary intakes and nutritional status; (2) incorporating rapid screening tools for routine monitoring and surveillance; (3) addressing critical research needs, including evaluations of the current ULs, improving biomarkers of excess, and developing methods for predicting and comparing risks and benefits; and (4) ensuring that relevant information is used in decision-making processes.

An Economic Model for Optimizing Effective Coverage of MN interventions: A Case Study of Cameroon.

Objectives: Micronutrient (MN) interventions are generally undertaken at national scale. New spatially disaggregated data on MN deficiencies in Cameroon suggest that subnational strategies may be more efficient, but methods to choose among alternative interventions are needed. We developed a tool to plan and manage sub-national MN interventions for Cameroon. Methods: Data from a nationally representative multi-stage cluster survey were used to determine the spatial distribution of MN deficiencies among population sub-groups at greatest risk. Macroregion-specific data (North, South, Douala/Yaoundé) on food intake were used to predict the effects of alternative MN intervention strategies on the prevalence of inadequate MN intake and absorption. MN supplements, fortified and biofortified foods, deworming and behavioral change communication to promote breastfeeding are among the interventions examined. Costs of alternative interventions were prepared. The costs and nutritional benefits of alternative interventions are included in an economic optimization model that chooses the best combination of MN interventions to ensure adequate MN intake, at regional level, over a ten-year planning horizon, given funding and other constraints. Results: Preliminary results indicate large spatial differences in MN deficiencies, e.g., estimated prevalence of vitamin A deficiency varied from ~62% (North region) to ~22% (Northwest region). Consumption of VA-rich foods and fortifiable foods also varies spatially. Hence, program efficiency may be enhanced by adopting targeted sub-national MN intervention strategies. Conclusions: Given spatial patterns in MN deficiencies, diet-driven effectiveness of alternative MN interventions, and costs of these interventions, sub-national MN interventions may offer efficiency gains that exceed the costs of planning and implementing them.