Exposure to aflatoxins and fumonisins and linear growth of children in rural Ethiopia: a longitudinal study

Abstract

Objective: We hypothesise that exposure to aflatoxins and fumonisins, measured in serum, alters protein synthesis, reducing serum protein and insulin-like growth factor 1 (IGF-1), increasing inflammation and infection, leading to child's linear growth failure.

Design: Children 6-35 months, stratified by baseline stunting, were subsampled from an intervention trial on quality protein maize consumption and evaluated at two time-points.

Setting: Blood samples and anthropometric data were collected in the pre-harvest (August-September 2015) and post-harvest (February 2016) seasons in rural Ethiopia.

Participants: 102 children (50 stunted and 52 non-stunted).

Results: Proportions of children exposed to aflatoxin G1, aflatoxin G2 and aflatoxin M1 were higher in the pre-harvest (8, 33 and 7, respectively) compared to post-harvest season (4, 28 and 4, respectively). The proportion of children exposed to any aflatoxin was higher in the pre-harvest than post-harvest season (51 % v. 41 %). Fumonisin exposure ranged from 0 % to 11 %. In joint statistical tests, aflatoxin exposure was associated with serum biomarkers of inflammation (C-reactive protein, α-1-glycoprotein) and protein status (transthyretin, lysine, tryptophan), IGF-1 and linear growth (all P < 0·01). However, exposure to specific aflatoxins was not significantly associated with any biomarkers or outcomes (all P > 0·05).

Conclusions: Aflatoxin exposure among rural Ethiopian children was high, with large variation between seasons and individual aflatoxins. Fumonisin exposure was low. There was no clear association between aflatoxin exposure and protein status, inflammation or linear growth. A larger study may be needed to examine the potential biological interactions, and the assessment of aflatoxins in food is needed to determine sources of high exposure.

Keywords: Aflatoxin; Ethiopia; Fumonisin; Inflammation; Linear growth; Protein status.

Fig. 1

Conceptual framework: (1) Aflatoxins exposure was measured by the biomarkers AFB1 lysine, AFB1, AFB2, AFG1, AFG2 and AFM1 from serum samples; (2) Inflammation was measured by inflammation biomarkers: C-reactive protein (CRP) and α-1-glycoprotein protein (AGP) concentration from serum samples; (3) Protein synthesis was measured by protein and amino acid biomarkers in serum: Insulin-like growth factor 1 (IGF-1), transthyretin, lysine and tryptophan; (4) Diarrhea was measured using the mother’s/female caregiver’s recall over the preceding two weeks; (5) Wealth tertiles were constructed based on household assets (primarily agricultural transportation and household implements) using principal component analysis (PCA); (6) Linear growth was measured using height-for-age Z-score (HAZ) and height-for-age difference (HAD)

Fig. 2

Pre- and post-harvest weighted prevalence of exposure to aflatoxins (a) and fumonisins (b) as measured in serum

Fig. 3

Mean weighted height-for-age Z-scores (HAZ, panel a) and weighted prevalence of stunting (panel b) in pre- and post-harvest seasons, by exposure to any aflatoxins in either season