Children's cognitive impairment associated with cassava cyanide in Democratic Republic of the Congo: Burden of disease

Abstract

Worldwide, tens of millions of children rely on cassava as a dietary staple throughout their formative years of brain and behavioral development. Recently, it was discovered that cassava cyanide can impair children's neurocognitive development at relatively low exposures. We revisited the World Health Organization's foodborne disease burden estimate of cassava cyanide, focusing on the new health endpoint of children's cognitive impairment in Democratic Republic of the Congo (DRC). The loss of Intelligence Quotient (IQ) scores was used to measure the endpoint of cognitive impairment caused by cassava cyanide exposure, which was estimated based on the concentration-effect relationship between children's IQ scores and cyanide concentrations in flour. We estimated the burden of intellectual disability (ID) associated with cassava cyanide exposure in terms of disability-adjusted life years (DALYs). The median content of cyanide in cassava samples collected from DRC was 12.5 mg/kg, causing a median decrement to children's IQ of 2.37 points. The estimated number of children with ID associated with cassava cyanide exposure was 1,643 cases, although 1,567 of these cases (95%) were mild ID. The burden of cognitive impairment attributable to cassava cyanide in DRC alone was 13,862 DALYs per 100,000 children, or 3.01 million for all children under age 5. The results of the study, showing a significant burden of cassava cyanide-related cognitive impairment in children even at relatively low doses, can contribute to the implementation of cost-effective interventions to make cassava consumption safer for children in high-risk rural areas of DRC.

Fig 1. Flowchart for the literature search on cassava cyanide and children’s cognitive impairment.

Fig 2. The change of individual cases with intellectual disability attributable to dietary exposure of cassava cyanide every 100,000 children.