Characterisation of Aflatoxin B1-Albumin Adducts as Biomarkers of Aflatoxin Exposure in Children with Stunted Growth in Kano State

Chronic aflatoxin exposure has been associated with impaired linear growth in children independent of nutritional status, and serum aflatoxin B1-albumin adducts provide a validated biomarker of medium-term aflatoxin exposure useful for investigating this relationship in northern Nigerian populations. This study characterises aflatoxin B1-albumin adduct levels as exposure biomarkers and examines their association with growth outcomes in stunted and non-stunted children in Kano State. A case-control study enrolled one hundred stunted children (height-for-age z-score below negative two) and one hundred non-stunted children aged two to five years from Kano Municipal and Ungogo LGAs, matched for age, sex, and socioeconomic status. Serum aflatoxin B1-albumin adducts were quantified by competitive ELISA using a validated kit. Dietary aflatoxin exposure was estimated by a food frequency questionnaire capturing groundnut, maize, and sorghum consumption frequencies and preparation methods. Serum albumin, insulin-like growth factor 1 (IGF-1), and insulin-like growth factor binding protein 3 (IGFBP-3) were measured as growth axis biomarkers. Results show significantly higher aflatoxin B1-albumin adduct levels in stunted children compared to non-stunted controls (median 18.4 vs 7.2 pg/mg albumin). Adduct levels correlated significantly and negatively with height-for-age z-score and with serum IGF-1 levels. Logistic regression confirmed that aflatoxin adduct level above the median was an independent risk factor for stunting after controlling for dietary protein intake and maternal education. The study provides mechanistic evidence linking aflatoxin exposure to IGF-1 pathway suppression and growth faltering in Kano children. Keywords: aflatoxin B1-albumin adducts, stunting, aflatoxin exposure, IGF-1, Kano State.