RESUMO
OBJECTIVE: To study the relationship between blood lead levels and cognitive abilities of children exposed to this metal. METHOD: This is a cross-sectional study that included 134 children aged 6 to 8.5 years old from 3 schools with different risks of lead exposure located in El Callao (Peru). Cognitive assessments were made by means of the Graphic Test of Reasoning (GTR) and the Kohs Block Design Test (KBDT). Blood lead levels and other laboratory tests were performed. RESULTS: Children with lead > 10 ug/dl presented greater prevalence of low scores in the Graphic Test of Reasoning (18.9% vs. 7.1%, p = 0.049) and in the Kohs Block Design Test (KBDT) (39.6% vs. 18.6%, p = 0.01) compared with those with lower lead blood levels. A deficit of 1 category in the Graphic Test of Reasoning was associated with an increase in lead blood level of 16.78 ug/dl (assuming a linear relationship) and from 1 to 5.19 ug/dl (logarithmic model). For each 10 ug/dl of increase in lead levels, the Kohs Block Design Test decreases in 6.24 units (12.91 in males and 0.216 in females) (linear model), and an increase from 1 to 10 ug/dl corresponds to a drop of 16.44 points in the Kohs Block Design Test (31.19 in males and 3.98 in females) (logarithmic model). Considering the Graphic Test of Reasoning subscales, lead levels correlated negatively with the areas of numerical problems (rho = -0.445, p < 0.001), numerical relationships (rho = -0.365, p < 0.001), inferences (rho = -0.281, p = 0.002) and similarities (rho = -0.250, p = 0.005). CONCLUSIONS: Lead levels were non-linearly associated with lower cognitive abilities, especially in males, being the numerical reasoning the most affected area.
Assuntos
Transtornos Cognitivos/etiologia , Cognição/efeitos dos fármacos , Exposição Ambiental/efeitos adversos , Inteligência/efeitos dos fármacos , Intoxicação do Sistema Nervoso por Chumbo na Infância/complicações , Chumbo/sangue , Criança , Transtornos Cognitivos/sangue , Transtornos Cognitivos/diagnóstico , Estudos Transversais , Feminino , Humanos , Testes de Inteligência , Modelos Lineares , Masculino , Peru , Distribuição por Sexo , Fatores SexuaisRESUMO
OBJETIVE: To study the relationship between blood lead levels and cognitive abilities of children exposed to this metal. METHOD: This is a cross-sectional study that included 134 children aged 6 to 8.5 years old from 3 schools with different risks of lead exposure located in El Callao (Peru). Cognitive assessments were made by means of the Graphic Test of Reasoning (GTR) and the Kohs Block Design Test (KBDT). Blood lead levels and other laboratory tests were performed. RESULTS: Children with lead > 10 ug/dl presented greater prevalence of low scores in the Graphic Test of Reasoning (18.9 percent vs. 7.1 percent, p = 0.049) and in the Kohs Block Design Test (KBDT) (39.6 percent vs. 18.6 percent, p = 0.01) compared with those with lower lead blood levels. A deficit of 1 category in the Graphic Test of Reasoning was associated with an increase in lead blood level of 16.78 ug/dl (assuming a linear relationship) and from 1 to 5.19 ug/dl (logarithmic model). For each 10 ug/dl of increase in lead levels, the Kohs Block Design Test decreases in 6.24 units (12.91 in males and 0.216 in females) (linear model), and an increase from 1 to 10 ug/dl corresponds to a drop of 16.44 points in the Kohs Block Design Test (31.19 in males and 3.98 in females) (logarithmic model). Considering the Graphic Test of Reasoning subscales, lead levels correlated negatively with the areas of numerical problems (rho = -0.445, p < 0.001), numerical relationships (rho = -0.365, p < 0.001), inferences (rho = -0.281, p = 0.002) and similarities (rho = -0.250, p = 0.005). CONCLUSIONS: Lead levels were non-linearly associated with lower cognitive abilities, especially in males, being the numerical reasoning the most affected area.
OBJETIVO: Estudar a relação entre níveis séricos de chumbo e funções cognitivas em crianças expostas a esse metal. MÉTODO: Este é um estudo transversal que incluiu 134 crianças de 6 a 8,5 anos de idade, de três escolas localizadas em El Callao (Peru), e com riscos diferentes de exposição ao chumbo. As avaliações de suas funções cognitivas foram realizadas utilizando-se o Teste Gráfico de Raciocínio e o Teste dos Cubos de Kohs. Foram medidos os níveis séricos de chumbo RESULTADOS: As crianças com níveis séricos de chumbo > 10 ug/dl apresentaram maior prevalência de baixa pontuação no Teste Gráfico de Raciocínio (18,9 por cento vs. 7,1 por cento, p = 0,049) e também no Teste dos Cubos de Kohs (39,6 por cento vs. 18,6 por cento, p = 0,01), quando comparadas com aquelas com níveis séricos menores. Um déficit de uma categoria no Teste Gráfico de Raciocínio foi associado com um aumento no nível sérico de chumbo de 16,78 ug/dl (assumindo uma relação linear) e de 1 a 5,19 ug/dl (modelo logarítmico). Para cada 10 ug/dl de aumento no nível sérico de chumbo, o Teste dos Cubos de Kohs apresentou diminuição de 6,24 unidades (12,91 para os meninos e 0,216 para as meninas) (modelo linear) e um aumento de 1 a 10 ug/dl correspondeu a uma diminuição de 16,44 pontos no Teste dos Cubos de Kohs (31,19 para os meninos e 3,98 para as meninas) (modelo logarítmico). Considerando as subescalas do Teste Gráfico de Raciocínio, os níveis séricos de chumbo correlacionaram-se negativamente com as áreas de problemas numéricos (rho = -0,445, p < 0,001), relações numéricas (rho = -0,365, p < 0,001), inferências (rho = -0,281, p = 0,002) e semelhanças (rho = -0,250, p = 0,005). CONCLUSÕES: Níveis séricos de chumbo foram associados de uma maneira não-linear com déficits das habilidades cognitivas, especialmente entre os meninos, sendo o raciocínio numérico a área mais afetada.