Postweaning exposure to aflatoxin results in impaired child growth: a longitudinal study in Benin, West Africa

Abstract

Aflatoxins are dietary contaminants that are hepatocarcinogenic and immunotoxic and cause growth retardation in animals, but there is little evidence concerning the latter two parameters in exposed human populations. Aflatoxin exposure of West African children is known to be high, so we conducted a longitudinal study over an 8-month period in Benin to assess the effects of exposure on growth. Two hundred children 16-37 months of age were recruited from four villages, two with high and two with low aflatoxin exposure (50 children per village). Serum aflatoxin-albumin (AF-alb) adducts, anthropometric parameters, information on food consumption, and various demographic data were measured at recruitment (February) and at two subsequent time points (June and October). Plasma levels of vitamin A and zinc were also measured. AF-alb adducts increased markedly between February and October in three of the four villages, with the largest increases in the villages with higher exposures. Children who were fully weaned at recruitment had higher AF-alb than did those still partially breast-fed (p < 0.0001); the major weaning food was a maize-based porridge. There was no association between AF-alb and micronutrient levels, suggesting that aflatoxin exposure was not accompanied by a general nutritional deficiency. There was, however, a strong negative correlation (p < 0.0001) between AF-alb and height increase over the 8-month follow-up after adjustment for age, sex, height at recruitment, socioeconomic status, village, and weaning status; the highest quartile of AF-alb was associated with a mean 1.7 cm reduction in growth over 8 months compared with the lowest quartile. This study emphasizes the association between aflatoxin and stunting, although the underlying mechanisms remain unclear. Aflatoxin exposure during the weaning period may be critical in terms of adverse health effects in West African children, and intervention measures to reduce exposure merit investigation.

Figure 1. AF-alb adduct GM level across the four villages at the three survey time points. The “Total” bars show the adduct level of all the villages at three survey points, with the overall adduct level at the October survey being significantly higher than the other two survey points (p < 0.01). Djidja and Dovi-Cogbe had significantly higher AF-alb than did Bagbe and Sedje at both the October and June survey points (p < 0.01 for both). However, at the February survey, the AF-alb adduct levels are different across all the villages (p < 0.01).

Figure 2. Adjusted mean AF-alb level in weaned and partially weaned children. Data used in this figure are from the February survey point, and the mean AF-alb levels (95% CI) are adjusted for age and SES. The differences between partially breast-fed and fully weaned children are significant in ANOVA, p = 0.0001.