Discussion with NUGAG members and stakeholders highlighted the limited evidence in some areas, meriting further research on intermittent iron supplementation in preschool and school-age children, in particular, in the following areas:

• the most effective and safe dose of folic acid that can be provided intermittently;
• provision of multiple micronutrients on an intermittent basis and their effects on other indicators of vitamin and mineral status, such as retinol and zinc;
• efficacy of intermittent iron regimens with regard to neurocognitive and developmental outcomes and growth (attempts should be made to use comparable measures across studies when possible);
• efficacy of intermittent supplementation in the treatment of anaemia, iron deficiency and iron deficiency anaemia, as well as the best therapeutic regimen (dose, frequency, duration);
• cost-effectiveness of intermittent compared with daily iron supplementation, taking into account more than just the cost differential of the supplements themselves;
• whether this intervention requires continuous or periodic implementation over the year, taking into account both biological and programmatic feasibility.

In addition, future studies are encouraged to comprehensively document the effects of intermittent supplementation on anaemia, iron deficiency, haemoglobin and ferritin concentrations and other indicators of iron status and inflammation. Reporting of side-effects in greater detail according to recommended definitions is highly desirable to better understand the factors influencing adherence. A more systematic and comparable reporting system addressing the relevance of direct and continued supervision is also needed.