Assessing the impact of micronutrient intervention programs implemented under special circumstances--meeting report

The World Food Programme and the Office of the United Nations High Commissioner for Refugees organized a meeting of experts to discuss evaluation of micronutrient interventions under special circumstances, such as emergency and refugee situations.

Multimicronutrient interventions for groups with higher needs may include home fortification products for young children or supplements for pregnant and lactating women. The choice of preparation should be guided by target group needs, evidence of efficacy of a product or its compounds, acceptability, and cost-effectiveness. Different designs can be used to assess whether an intervention has the desired impact. First, program implementation and adherence must be ascertained. Then, impact on micronutrient status can be assessed, but design options are often limited by logistic challenges, available budget, security issues, and ethical and practical issues regarding nonintervention or placebo groups. Under these conditions, a plausibility design using pre- and postintervention cross-sectional surveys, a prospective cohort study, or a step-wedge design, which enrolls groups as they start receiving the intervention, should be considered. Post hoc comparison of groups with different adherence levels may also be useful. Hemoglobin is often selected as an impact indicator because it is easily measured and tends to respond to change in micronutrient status, especially iron. However, it is not a very specific indicator of micronutrient status, because it is also influenced by inflammation, parasitic infestation, physiological status (age, pregnancy), altitude, and disorders such as thalassemia and sickle cell disease.

Given the constraints described above, replicability of impact in different contexts is key to the validation of micronutrient interventions.