Dietary cyanogen exposure and early child neurodevelopment: An observational study from the Democratic Republic of Congo

Abstract

BackgroundDietary cyanogen exposure from ingesting bitter (toxic) cassava as a main source of food in sub-Saharan Africa is related to neurological impairments in sub-Saharan Africa. We explored possible association with early child neurodevelopmental outcomes.MethodsWe undertook a cross-sectional neurodevelopmental assessment of 12–48 month-old children using the Mullen Scale of Early Learning (MSEL) and the Gensini Gavito Scale (GGS). We used the Hopkins Symptoms Checklist-10 (HSCL-10) and Goldberg Depression Anxiety Scale (GDAS) to screen for symptoms of maternal depression-anxiety. We used the cyanogen content in household cassava flour and urinary thiocyanate (SCN) as biomarkers of dietary cyanogen exposure. We employed multivariable generalized linear models (GLM) with Gamma link function to determine predictors of early child neurodevelopmental outcomes.ResultsThe mean (SD) and median (IQR) of cyanogen content of cassava household flour were above the WHO cut-off points of 10 ppm (52.18 [32·79]) and 50 (30–50) ppm, respectively. Mean (SD) urinary levels of thiocyanate and median (IQR) were respectively 817·81 (474·59) and 688 (344–1032) μmole/l in mothers, and 617·49 (449·48) and 688 (344–688) μmole/l in children reflecting individual high levels as well as a community-wide cyanogenic exposure. The concentration of cyanide in cassava flour was significantly associated with early child neurodevelopment, motor development and cognitive ability as indicated by univariable linear regression (p < 0.05). After adjusting for biological and socioeconomic predictors at multivariable analyses, fine motor proficiency and child neurodevelopment remained the main predictors associated with the concentration of cyanide in cassava flour: coefficients of -0·08 to -.15 (p < 0·01). We also found a significant association between child linear growth, early child neurodevelopment, cognitive ability and motor development at both univariable and multivariable linear regression analyses coefficients of 1.44 to 7.31 (p < 0·01).ConclusionDietary cyanogen exposure is associated with early child neurodevelopment, cognitive abilities and motor development, even in the absence of clinically evident paralysis. There is a need for community-wide interventions for better cassava processing practices for detoxification, improved nutrition, and neuro-rehabilitation, all of which are essential for optimal development in exposed children.

Konzo: a distinct neurological disease associated with food (cassava) cyanogenic poisoning

“…More recently, we showed that subjects affected by the disease also have poor neurodevelopmental trajectories including decline in motor and cognitive performances while still relying on improperly processed cassava as the main source of food (Boivin et al, 2017). Our most recent work has extended these findings to children as young as one year of age, suggesting that cassava-associated neurotoxicity may begin when children are weaned from breast milk to cassava porridge (Kashala-Abotnes et al, 2018). In documenting neurocognitive impairments in children with Konzo, Boivin and colleagues also noted sub-clinical symptoms even in Konzo-free children living in Konzo-affected households.…”

“…Samples of cassava flour and urines in a study of very young children had similar concentrations. The cyanogen content in cassava flour was above the safe limit of 10 ppm (Organization FaAOWH, 2018) and the level of SCN urinary excretion was above 350 μmole/litre in most households (Kashala-Abotnes et al, 2018). The introduction of a new food-processing method has helped reduce the cyanogenic content of cassava and hence, the levels of exposure to its cyanogenic compounds, and a subsequent decrease in the number of incident cases of Konzo was noted in select areas of DRC and Tanzania (Mlingi et al, 2011; Banea et al, 2013, 2014; Banea et al, 2012).…”

Antidotal Effects of the Phenothiazine Chromophore Methylene Blue Following Cyanide Intoxication

“…Of note, in many countries, children are exposed to naturally occurring compounds containing CN, present in their food, such as in apricot kernels (Chaouali et al, 2013;Cigolini et al, 2011;Gerivani et al, 2016;Kupper et al, 2008;Sauer et al, 2015;Vlad et al, 2015) or cassava (Ariffin et al, 1992). Ingestion of CN contained in the cassava plant has been linked not only to dreadful outbreaks of spastic paralysis with myoclonus in tropical regions of Africa in adults (Tagwireyi et al, 2016), but also to death (Ariffin et al, 1992) and developmental deficits (Kashala-Abotnes et al, 2018) during acute exposure in children.…”

Microscopic Characteristics, Chromatographic Profiles and Inhibition of Peroxidase Activity of the Leaves of &lt;i&gt;Manihot esculenta&lt;/i&gt; and &lt;i&gt;Manihot glaziovii&lt;/i&gt;, Consumed as Traditional Vegetables

“…Kahemba is a rural area of the Kwango region in DRC, which is severely affected by konzo. Konzo is a neurological disease associated with chronic dietary reliance on foodstuffs from insufficiently processed bitter cassava [5]. Cassava cultivars (varieties) are classified as sweets and bitters cassava.…”