To assess the effect on the haemoglobin concentrations of schoolchildren of weekly iron tablets administered by teachers.

Sixty schools were randomly assigned to two groups: in 30 schools children were given weekly for 10 weeks a tablet providing 65 mg of iron and 0.25 mg of folic acid; in the other 30 schools no iron tablets were given. All children were dewormed and given vitamin A before the study began. The haemoglobin concentration of up to 20 randomly selected children in each school was estimated before and 2 weeks after the end of treatment.

Rural community schools in Kolondieba district of Mali.

Some 1113 schoolchildren aged 6–19 years with a mean of 11.4 years.

The haemoglobin concentration of treated children rose on average by 1.8 g l-1 (P < 0.001) and the prevalence of anaemia fell by 8.2% (P < 0.001); in untreated children the haemoglobin concentration fell by an average of -2.7 g l-1 (P < 0.001) and the prevalence of anaemia rose by 9.4% (P < 0.001). The fall in haemoglobin concentration among untreated girls of -4.0 g l-1 was greater than in untreated boys (-0.3 g l-1, P < 0.001).

Weekly iron tablets given by teachers prevented a general fall in the haemoglobin concentrations of untreated children, and led to a small but statistically significant rise among treated children (P < 0.001). Young children benefited more than children aged ≥12 years, and girls benefited more than boys.