Evidence for an association between hookworm infection and cognitive function in Indonesian school children

The association between helminth infection and cognitive and motor function was investigated in school-age children in Java, Indonesia. 432 children f rom 42 primary schools participated in the study Children were stratified b y age and sex into two age groups, 8-9 years and 11-13 years. Children infe cted with hookworm performed significantly worse than children without hook worm infection in 6 of the 14 cognitive or motor tests. After controlling f or school (as a random effect) plus age, socio-economic status and parental education, sex, stunting (height-for-age < - 2sd), body mass index, haemog lobin concentration and the presence tf A. lumbricoides and T. trichiura in fections, infection with hookworm explained significantly lower scores on t ests of Fluency (P < 0.01), Digit-Span Forwards (P < 0.01), Number Choice ( P < 0.01), Picture Search (P < 0.03), Stroop Colour Word (P < 0.02) and Maz es (P < 0.001). In 4 of the 6-tests (Fluency, Number Choice, Picture Search and Mazes). there was a significant interaction between hookworm infection and age (P < 0.03), indicating that the association between hookworm and l ower rest scores increased with age. No associations were observed between hookworm infection and scores in tot, of Digit-Span Backwards, Corsi-Block, Stroop Colour, Scroop Interference, Free Recall, Verbal Analogies, Bead Th reading or the Pegboard. (P > 0.05). Tests associated with helminths repres ented various functions of working memory. No significant associations betw een helminth infection and motor function were observed that could not be e xplained by chance. The results suggest that hookworm infection can bale a significant adverse effect on children's working memory which may have cons equences for a child's reasoning ability and reading comprehension. Althoug h the results are only associational, che fact that differences in cognitio n were observed at baseline imply that Preventing infection with helminths in school-age children could be of benefit.