Schistosomiasis
Serum concentration of micronutrients in relation to schistosomiasis and
indicators of infection: a cross-sectional study among rural Zimbabwean
schoolchildren.
Friis H; Ndhlovu P; Kaondera K; Sandstrom B; Michaelsen KF; Vennervald
BJ; Christensen NO
Eur J Clin Nutr 1996 Jun;50(6):386-91 OBJECTIVE: To study the
relation between indicators of infection and Schistosoma mansoni and S.
haematobium infection, and serum concentrations of zinc, ferritin and
retinol. DESIGN: Cross-sectional. SETTING AND SUBJECTS: 313 rural Zimbabwean
schoolchildren (144 boys and 169 girls, 11-17 years). VARIABLES: S. mansoni
and S. haematobium egg output, concentration of C-reactive protein, neutrophil
count, questionnaire data on fever and diarrhoea, and serum concentrations
of retinol, ferritin and zinc. RESULTS: Age, elevated CRP, fever and S.
mansoni egg output were significant predictors of the concentration of
retinol. The regression coefficient for age was positive, and negative
for elevated CRP, fever and S. mansoni egg output. As S. mansoni, but
not S. haematobium, was of significance, it is unlikely that low retinol
level increased susceptibility to infection. The effect of S. mansoni
on retinol level was 0.03 mumol/l (95% CI: 0.002-0.06, P = 0.03) for each
100 eggs/g increase in egg output. Neither indicators of infection nor
age and sex were predictors of concentration of zinc and log10 concentration
of ferritin. CONCLUSION: S. mansoni infection reduced retinol level, when
indicators of infection and age were controlled for. High intensities
of S. mansoni infection may induce vitamin A deficiency among children
with marginal vitamin A status. The study emphasizes the importance of
controlling for age and metabolic response to concurrent infections in
studies using serum retinol as a measure of vitamin A status.
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