Hookworm, Ascaris lumbricoides infection and polyparasitism associated with poor cognitive performance in Brazilian schoolchildren

Abstract

Summaryobjective To investigate the relationship between hookworm and Ascaris lumbricoides infection and performance on three subsets of the Wechsler Intelligence Scale for Children -third edition (WISC-III) (Digit Span, Arithmetic and Coding) and Raven Colored Progressive Matrices.methods Cross-sectional study of 210 children between the ages of 6 and 11 years in Americaninhas, Minas Gerais, Brazil. Separate proportional odds models were used to measure the association between the intensity of helminth infections and poor performance on each of the four cognitive tests.results After adjusting for sex, age, socioeconomic status and other helminth infections, moderate-tohigh-intensity hookworm infection was associated with poor performance on the WISC-III Coding subtest [OR = 3.20; 95% confidence interval (CI) = 1.43-7.17], low intensity of hookworm infection was associated with poor performance on the WISC-III Coding subtest [odds ratio (OR) = 3.71; 95% CI = 1.80-7.66] and moderate-to-high-intensity A. lumbricoides infection was associated with poor performance on the Raven test (OR = 2.03; 95% CI = 1.04-3.99), all in comparison with uninfected children. Children co-infected with A. lumbricoides infection and hookworm infection had greater odds of poor performance on some WISC-III subtests than children with only A. lumbricoides infection.conclusions These findings suggest that hookworm infection may be associated with poorer concentration and information processing skills, as measured on the WISC-III Coding subtest, and that A. lumbricoides infection may be associated with poorer general intelligence, as measured through the Raven Colored Progressive Matrices. This study also presents evidence that polyparasitized children experience worse cognitive outcomes than children with only one helminth infection.

RETRACTED: Parasite prevalence and the worldwide distribution of cognitive ability

“…For example, Bleakley (2007) studied the effects of eradication of hookworm in the southern US during the early twentieth century, and found that areas where hookworm infections had been greatly reduced had higher average incomes after treatment than areas that had not received treatment. Jardin-Botelho et al (2008) found that Brazilian children infected with hookworm performed more poorly on cognitive tests than uninfected children, and that children infected with more than one type of intestinal helminth performed more poorly than children infected with only one.…”

Effect of Deworming on Indices of Health, Cognition, and Education Among Schoolchildren in Rural China: A Cluster-Randomized Controlled Trial

“…The WISC-IV tests were culturally adapted, translated, and edited into simplified Chinese and validated for assessment among Chinese children in 2008. 33 According to the literature, children's working memory and processing speed are the cognitive areas that are most likely to be affected by STH infection 34,35 ; thus, we focused our efforts on measuring these two outcomes. In the WISC-IV, Working Memory Index (WMI) is assessed through two core subtests: Digit Span and Letter Number Sequencing.…”

Co-Infections of Asymptomatic Malaria and Soil-Transmitted Helminths in School Children in Localities with Different Levels of Urbanization in the Mount Cameroon Region

“…STHs also cause anemia through blood loss, nutritional theft and loss of appetite due to immunological factor [6]. Therefore children with multiple parasitic infections especially those with heavy infection intensity tend to experience more cognitive outcomes and other health problems such as malnutrition than those with single infections [28].…”