Association of Blood Lead Level with Neurological Features in 972 Children Affected by an Acute Severe Lead Poisoning Outbreak in Zamfara State, Northern Nigeria

Abstract

BackgroundIn 2010, Médecins Sans Frontières (MSF) investigated reports of high mortality in young children in Zamfara State, Nigeria, leading to confirmation of villages with widespread acute severe lead poisoning. In a retrospective analysis, we aimed to determine venous blood lead level (VBLL) thresholds and risk factors for encephalopathy using MSF programmatic data from the first year of the outbreak response.Methods and FindingsWe included children aged ≤5 years with VBLL ≥45 µg/dL before any chelation and recorded neurological status. Odds ratios (OR) for neurological features were estimated; the final model was adjusted for age and baseline VBLL, using random effects for village of residence. 972 children met inclusion criteria: 885 (91%) had no neurological features; 34 (4%) had severe features; 47 (5%) had reported recent seizures; and six (1%) had other neurological abnormalities. The geometric mean VBLLs for all groups with neurological features were >100 µg/dL vs 65.9 µg/dL for those without neurological features. The adjusted OR for neurological features increased with increasing VBLL: from 2.75, 95%CI 1.27–5.98 (80–99.9 µg/dL) to 22.95, 95%CI 10.54–49.96 (≥120 µg/dL). Neurological features were associated with younger age (OR 4.77 [95% CI 2.50–9.11] for 1–<2 years and 2.69 [95%CI 1.15–6.26] for 2–<3 years, both vs 3–5 years). Severe neurological features were seen at VBLL <105 µg/dL only in those with malaria.InterpretationIncreasing VBLL (from ≥80 µg/dL) and age 1–<3 years were strongly associated with neurological features; in those tested for malaria, a positive test was also strongly associated. These factors will help clinicians managing children with lead poisoning in prioritising therapy and developing chelation protocols.

Health and ecological hazards due to natural radioactivity in soil from mining areas of Nasarawa State, Nigeria

“…The Zamfara lead poisoning was termed as the worst lead poisoning epidemic in human history [54]. The health consequence of the Zamfara lead poisoning is reported in recent literature [55][56][57]. Despite the fact that one of the daughter nuclides of 210 Pb has been identified as a powerful alpha emitter that is used in radiation poisoning [58,59], till date, no study has considered the radio toxicity of the Zamfara lead poisoning.…”

Respiratory tract infection associated with seizures

“…28 Non-infectious causes of encephalopathy in children include cerebrovascular events, metabolic disorders, endocrine disorders (including diabetic ketoacidosis), hepatic failure, renal failure, poisoning, substance misuse, and iatrogenic causes (such as anticonvulsant overdose or withdrawal and opioid overdose or withdrawal). [28][29][30][31][32][33] For personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribe…”

Developmental Exposure to Lead

“…Indeed, significantly elevated blood lead levels are the norm for many children in countries that have not phased lead out of gasoline [12]. A notable tragedy has unfolded over the past several years in Nigeria, where activities related to gold mining have resulted in widespread lead exposures and what has been described as the worst outbreak of lead poisoning in modern history, killing hundreds of children [18][19][20][21]. A notable tragedy has unfolded over the past several years in Nigeria, where activities related to gold mining have resulted in widespread lead exposures and what has been described as the worst outbreak of lead poisoning in modern history, killing hundreds of children [18][19][20][21].…”