Effectiveness of intermittent iron and high-dose vitamin A supplementation on hemoglobin, iron and vitamin A status of schoolchildren in southern Ethiopia: a randomized placebo controlled trial.

OBJECTIVE

We assessed the effectiveness of weekly iron and semestrial high-dose vitamin A supplementation on hemoglobin (Hb) concentration, and iron and vitamin A status of schoolchildren in rural Ethiopia.

METHOD: Using a 2 × 2 factorial design, 504 schoolchildren aged 7-10 years were randomly assigned to one of the four arms: control placebo; high-dose vitamin A; iron; or iron and high-dose vitamin A. Semestrial 200,000 IU vitamin A and weekly 42 mg of iron supplement were provided for 11 months. At baseline and at endline, Hb and serum concentrations of ferritin (sF), soluble transferrin receptor (sTfR), and retinol-binding protein (RBP) were measured. Serum indicators were adjusted for inflammation indicators, while Hb was adjusted for village altitude. Total body iron was calculated from sTfR and sF concentrations using an established formula.

RESULT: At baseline, prevalence of anemia (Hb < 11.0 g/dL), iron deficiency (sTfR > 8.3 mg/L or sF < 15 μg/L), iron-deficiency anemia, and vitamin A deficiency (RBP < 0.7 μmol/L) were 27.8%, 21.7%, 6.3% and 12.2%, respectively. Both iron and vitamin A supplementation had no significant effect on Hb, sTfR, and RBP concentrations. Supplementing iron weekly significantly increased sF (6.86 μg/L, 95%CI: 1.67, 12.05) and total body iron (0.45 mg/Kg, 95%CI: 0.17, 0.74), while semestrial vitamin A supplementation had no significant effect on both sF and total body iron.

CONCLUSION

Intermittent iron and vitamin A supplementation had no significant detectable effects on Hb, sTfR, and RBP concentrations of schoolchildren. Weekly iron supplementation improved sF concentrations. These findings suggest that providing iron and vitamin A supplements to populations where the extent of the deficiencies is not a major public health problem may not be beneficial.