Screening for neurocognitive deficits in adult populations reliant on toxic cassava as the main source of food

Context and objective. Chronic dietary reliance on improperly processed cyanogenic toxic cassava is widespread in sub-Saharan Africa. The objective of the present study was to screen for neurocognition impairments and daily-life functioning in adults with dietary dependency on cyanogenic cassava as the main source of food. Methods. A cross-sectional design enrolled heads of households (in couples) in the rural district of Kahemba, Democratic Republic of Congo. Participants were screened for neurocognitive impairments using the Community Screening Interview for Dementia (CSID). Detailed neuropsychiatric evaluations were performed and disease entities classified according to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria when applicable. Cassava cyanogenic exposure was ascertained by urinary concentrations of thiocyanate (SCN). Regression models were used to identify predictors of CSID performance at the 0.05 significance level. Results. For hundred and six households (203 couples, mean age 38.4 ± 11. 4 years) were involved. One hundred thirty-six subjects (33.5 %) [69 women and 67 men, mean age 39 ± 14.4 years)] and 13 (3.2 %) [7 women and 6 men, mean age: 32 ± 2.6 years] fulfilled the criteria for mild cognitive impairment (MCI) and Major Neurocognitive disorder (MNCD), respectively. The overall mean urinary concentration of SCN was 949.5+518.3 mol/l after adjusting Context and objective. Chronic dietary reliance on improperly processed cyanogenic toxic cassava is widespread in sub-Saharan Africa. The objective of the present study was to screen for neurocognition impairments and daily-life functioning in adults with dietary dependency on cyanogenic cassava as the main source of food. Methods. A cross-sectional design enrolled heads of households (in couples) in the rural district of Kahemba, Democratic Republic of Congo. Participants were screened for neurocognitive impairments using the Community Screening Interview for Dementia (CSID). Detailed neuropsychiatric evaluations were performed, and disease entities classified according to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria when applicable. Cassava cyanogenic exposure was ascertained by urinary concentrations of thiocyanate (SCN). Regression models were used to identify predictors of CSID performance at the 0.05 significance level. Results. For hundred and six households (203 couples, mean age 38.4 ± 11. 4 years) were involved. One hundred thirty-six subjects (33.5 %) [69 women and 67 men, mean age 39 ± 14.4 years)] and 13 (3.2 %) [7 women and 6 men, mean age: 32 ± 2.6 years] fulfilled the criteria for mild cognitive impairment (MCI) and Major Neurocognitive disorder (MNCD), respectively. The overall mean urinary concentration of SCN was . for age, gender, nutritional status, and history of konzo, neurocognition domain-specific deficits were independently associated with either hypertension or USCN (350mol / l incremental increase in excretion Functional impairments in daily-life activities increased as subjects poorly performed at the CSID screening (Spearman r = - .2, p < 0.01). Conclusion. Neurocognitive deficits in adults are common in Congolese adults relying on cyanogenic cassava as the main source of food. Our study findings warrant further studies to elucidate the overall lifespan brain/behavioral burden and mechanisms of cassava toxicity among adults with dietary dependency on cyanogenic cassava as the main source of food

Concurrent exposure to heavy metals and cognition in school-age children in Congo-Kinshasa: A complex overdue research agenda.

The impact of concurrent exposure to neurotoxic metals is a significant threat to brain function, mostly in contexts of multiple exposures as seen in the developing world. Ninety-five children (46 boys and 49 girls, 6 to 11-year old) from Congo-Kinshasa were assessed for cognition using the Kaufman Assessment Battery for Children (2nd edition) and exposure to Cr, Cu, Zn, Co, Mn, As, Cd, Se, Hg, Fe, and Pb by inductively coupled plasma mass spectrometry (ICPMS) in serum and urine collections. Concentrations of elements were all above normal ranges except for Cd, Se and Hg. General linear mixed effects models were used to predict neurocognitive outcomes with variable selection methods including backward elimination, elastic net, or subsets identified based on subject matter expertise. After adjusting for sex, age, and SES, urinary Co > 5 µg/l was associated with poor simultaneous processing (memory) (p = 0.0237). Higher excretion but normal concentration of Cd in serum was associated with better memory (p = 0.03), planning (p = 0.05), and overall performance scores (p < 0.01); thus appeared to be neuroprotective. However, higher excretion of Zn had negative influence on the overall performance scores (p = 0.02). Predictive neurotoxicology is a challenging task in contexts of multiple and concurrent exposures. Urinary Co > 5 µg/l is a risk factor for poor neurodevelopmental outcomes in such contexts. The impact of heavy metals on cognition is dependent on concentrations of and interactions between toxic and essential elements.