H. Sakti et al., Evidence for an association between hookworm infection and cognitive function in Indonesian school children, TR MED I H, 4(5), 1999, pp. 322-334
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.