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

<div><p>Background</p><p>Dietary 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.</p><p>Methods</p><p>We 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.</p><p>Results</p><p>The mean (<i>SD</i>) 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 (<i>SD</i>) 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 (<i>p</i> < 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 (<i>p</i> < 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 (<i>p</i> < 0·01).</p><p>Conclusion</p><p>Dietary 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.</p></div

Mullen Scale for Early Learning and Gensini Gavito Scale scores of the 114 studied children aged 12–48 months old in Kahemba, Democratic Republic of Congo.

<p>Mullen Scale for Early Learning and Gensini Gavito Scale scores of the 114 studied children aged 12–48 months old in Kahemba, Democratic Republic of Congo.</p

Overall and by household groups crude coefficient (<i>p</i>-value) from the univariable linear regression for scores derived from Mullen Scale of Early Learning, Gensini Gavito Scale, and cassava cyanogen content for the 114 studied children aged 12–48 months in Kahemba, democratic republic of Congo.

<p>Overall and by household groups crude coefficient (<i>p</i>-value) from the univariable linear regression for scores derived from Mullen Scale of Early Learning, Gensini Gavito Scale, and cassava cyanogen content for the 114 studied children aged 12–48 months in Kahemba, democratic republic of Congo.</p

Demographic, maternal, and child characteristics of the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.

<p>Demographic, maternal, and child characteristics of the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.</p

Proportion of different factors related to the child’s medical and perinatal history, parental level of education, stimulation & learning opportunities for the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.

<p>Proportion of different factors related to the child’s medical and perinatal history, parental level of education, stimulation & learning opportunities for the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.</p

Overall and by household groups crude coefficient (<i>p</i>-value) from multivariable linear regression and GLM analysis Gamma function (Italic) for scores derived from Mullen Scale of Early Learning and Gensini Gavito Scale for the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.

<p>Overall and by household groups crude coefficient (<i>p</i>-value) from multivariable linear regression and GLM analysis Gamma function (Italic) for scores derived from Mullen Scale of Early Learning and Gensini Gavito Scale for the 114 studied children aged 12–48 months in Kahemba, Democratic Republic of Congo.</p

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Dietary cyanogen cassava content and urinary thiocyanate excretion for the studied 114 children aged 12–48 months in Kahemba, Democratic Republic of Congo.

<p>Dietary cyanogen cassava content and urinary thiocyanate excretion for the studied 114 children aged 12–48 months in Kahemba, Democratic Republic of Congo.</p

Illustrative example of neurodisability in konzo.

<p>(A) Spastic stance in a boy severely affected by konzo. (B) Depiction of deficits at KABC-II cognition testing. (C) Deficits in fine motor control at the BOT-2 testing.</p

Age, biochemical measures and neurocognitive proficiency scores by konzo status.

<p>Children with konzo had low concentrations of serum albumin, plasma SCN, and neurology proficiency scores. They had, however, higher concentrations of serum triglycerides and 8,12-iso-iPF2<b>α</b>-VI isoprostane relative to those with no konzo.</p><p>Age, biochemical measures and neurocognitive proficiency scores by konzo status.</p