Effects of the Zanzibar school-based deworming program on iron status of children

Rebecca J. Stoltzfus, Marco Albonico, Hababuu M. Chwaya, James M. Tielsch, Kerry J. Schulze, Lorenzo Savioli

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


We evaluated the effects of the Zanzibar school-based deworming program on the iron status of primary school children. Parasitologic and nutritional assessments were carried out at baseline, 6 mo, and 12 mo in 4 nonprogram schools (n = 1002), 4 schools in which students received twice-yearly deworming (n = 952), and 4 schools in which students received thrice-yearly deworming (n = 970) with 500 mg generic mebendazole. Schools were randomly selected for evaluation and allocated to program groups. Relative to no treatment, thrice-yearly deworming caused significant decreases in protoporphyrin concentrations and both deworming regimens caused marginally significant increases in serum ferritin concentrations. The average annual changes in protoporphyrin concentrations were -5.9 and -23.5 μmol/mol heme in the control and thrice-yearly deworming groups, respectively (P <0.001). The average changes in ferritin concentration were 2.8 and 4.5 μg/L, respectively (P = 0.07). Deworming had no effect on annual hemoglobin change or prevalence of anemia. However, the relative risk of severe anemia (hemoglobin <70 g/L) was 0.77 (95% confidence limits: 0.39, 1.51) in the twice-yearly deworming group and 0.45 (0.19, 1.08) in the thrice-yearly deworming group. The effects on prevalence of high protoporphyrin values and incidence of moderate-to-severe anemia (hemoglobin < 90 g/L) were significantly greater in children with > 2000 hookworm eggs/g feces at baseline. We estimate that this deworming program prevented 1260 cases of moderate-to-severe anemia and 276 cases of severe anemia in a population of 30 000 schoolchildren in 1 y. Where hookworm is heavily endemic, deworming programs can improve iron status and prevent moderate and severe anemia, but deworming may be needed at least twice yearly.

Original languageEnglish (US)
Pages (from-to)179-186
Number of pages8
JournalAmerican Journal of Clinical Nutrition
Issue number1
StatePublished - 1998


  • Africa
  • Anemia
  • Anthelmintic drug
  • Deworming
  • Helminth
  • Hookworms
  • Humans
  • Iron deficiency
  • Schoolchildren
  • Zanzibar

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


Dive into the research topics of 'Effects of the Zanzibar school-based deworming program on iron status of children'. Together they form a unique fingerprint.

Cite this