Moderate- and low-intensity co-infections by intestinal helminths and Schistosoma mansoni, dietary iron intake, and anemia in Brazilian children.

To determine the role of moderate- and low-intensity infections with Schistosoma mansoni and intestinal helminths (hookworm, Trichuris trichiura, Ascaris lumbricoides) on the prevalence of anemia and their relationship to iron consumption, a cross-section of 1,709 children in rural Brazil was studied. All participants were selected for infection with one or multiple helminthic parasites, and demographic, anthropometric, and dietary intake were surveyed. The prevalence and intensity were as follows: hookworm infection, 15.7% and 8.6 eggs/g; T. trichiura, 74.8% and 190.5 eggs/g; A. lumbricoides, 63% and 1,905.5 eggs/g; S. mansoni, 44.5% and 60.3 eggs/g. There was no increase in odds ratio for anemia with any combination of intestinal helminths without S. mansoni infection. By logistic regression, the odds ratio for having anemia when infected with S. mansoni and two intestinal helminths was 1.7 (95% CI, 1.1-2.5) and for S. mansoni and three intestinal helminths was 2.4 (95% CI, 1.2-4.6) compared with children with a single parasite species. Children with an adequate intake of iron had no increased odds of anemia independent of the combination of parasite infections.

Fatores de risco para anemia por deficiência de ferro em crianças e adolescentes parasitados por helmintos intestinais / Risk factors for iron-deficiency anemia in children and adolescents with intestinal helminthic infections

OBJETIVO: Investigar os fatores de risco para anemia por deficiência de ferro em crianças e adolescentes (7 a 17 anos) infectados por helmintos. MÉTODOS: Foi realizado um estudo transversal com 1709 crianças e adolescentes residentes na cidade de Jequié, Estado da Bahia, Brasil, que apresentavam infecçäo leve ou moderada por Schistosoma mansoni, Ascaris lumbricoides, Trichuris trichiura e ancilostomídeos. Foram obtidos dados sobre níveis de hemoglobina (hemoglobinômetro portátil), consumo alimentar (inquérito recordatório de 24 horas), infecçäo parasitária (método Kato-Katz), condiçöes ambientais e domiciliares, renda e escolaridade dos responsáveis. Os fatores de risco para anemia na populaçäo foram estudados com base em um modelo hierárquico de causalidade. RESULTADOS: A prevalência de infecçäo por T. trichiura, A. lumbricoides, S. mansoni e ancilostomídeos foi de 74,8, 63,0, 55,5 e 15,7 por cento, respectivamente. Constatou-se que 32,2 por cento das crianças e adolescentes eram anêmicos. Depois do ajuste para variáveis de confusäo, os resultados da análise multivariada mostraram que a renda familiar per capita abaixo de um quarto do salário mínimo (27 dólares), o sexo masculino, a faixa etária de 7 a 9 anos e a ingestäo inadequada de ferro biodisponível foram significativamente associados à anemia. CONCLUSÖES: As açöes para controle da anemia no grupo de maior risco, conforme identificado no presente estudo, devem visar o aumento do consumo de alimentos ricos em ferro e da biodisponibilidade do ferro ingerido, bem como a melhoria das condiçöes sócio-ambientais.

[Risk factors for iron-deficiency anemia in children and adolescents with intestinal helminthic infections]. / Fatores de risco para anemia por deficiência de ferro em crianças e adolescentes parasitados por helmintos intestinais.

OBJECTIVE: To investigate risk factors for iron-deficiency anemia in children and adolescents (7 to 17 years of age) with intestinal helminthic infections. METHODS: A cross-sectional study was carried out with 1 709 children and adolescents living in Jequié, a town in the state of Bahia, Brazil, who had mild to moderate infection by Schistosoma mansoni, Ascaris lumbricoides, Trichuris trichiura, or hookworms. We obtained data concerning hemoglobin levels (using a portable hemoglobinometer), dietary habits (24-hour dietary recall), parasitic infections (Kato-Katz method), sanitary conditions (water supply, sewage connection, garbage collection), housing conditions (type of construction, number of persons per room), income, and amount of schooling of the parents or guardians. The risk factors for anemia were studied based on a hierarchical model of causality. RESULTS: The prevalence of parasitic infection was 74.8% for T. trichiura, 63.0% for A. lumbricoides, 55.5% for S. mansoni, and 15.7% for hookworms. Among the children and adolescents studied 32.2% were anemic. After adjustment for confounding variables, the results of the multivariate analysis showed that the following variables were significantly associated with anemia: per capita family income below US$ 27 (equal to one fourth of the Brazilian minimum wage), male sex, age of 7 to 9 years, and inadequate intake of bioavailable iron. CONCLUSIONS: The initiatives to control anemia in the group at greatest risk, as identified in this study, should seek to increase the consumption of iron-rich foods, boost the bioavailability of the iron ingested, and improve socioenvironmental conditions.