The strengths of the study are that it is a carefully conducted
randomized controlled trial with very low attrition and very high
compliance [12]. An important limitation to the study was that it
was not designed primarily to measure an effect on Hb concentration
or on the risk of anemia, as the primary objective of the
study was the effect on acute infections [12]. Furthermore there are
multiple risks for anemia including iron deficiency, treating the
children with folic acid and/or vitamin B12 without preventing
other limiting factors might have underestimated the efficacy of
these vitamins on the Hb concentration.