title: 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: BACKGROUND
  In 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.
  
  
  RESULTS
  We 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.
  
  
  CONCLUSIONS
  Increasing 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.
authors.affiliation: Manson Unit, Médecins Sans Frontières, London, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Greig
authors.affiliation: Public Health Department, Médecins Sans Frontières, Amsterdam, The Netherlands.
authors.forename: Natalie
authors.initials: N
authors.lastname: Thurtle
authors.affiliation: Public Health Department, Médecins Sans Frontières, Amsterdam, The Netherlands.
authors.forename: Lauren
authors.initials: L
authors.lastname: Cooney
authors.affiliation: Medical Statistics Department, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Cono
authors.initials: C
authors.lastname: Ariti
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Abdulkadir Ola
authors.initials: AO
authors.lastname: Ahmed
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Teshome
authors.initials: T
authors.lastname: Ashagre
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Anthony
authors.initials: A
authors.lastname: Ayela
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Kingsley
authors.initials: K
authors.lastname: Chukwumalu
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Alison
authors.initials: A
authors.lastname: Criado-Perez
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Camilo
authors.initials: C
authors.lastname: Gómez-Restrepo
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Meredith
authors.affiliation: Centers for Disease Control and Prevention, National Center for Environmental Health, Atlanta, Georgia, United States of America.
authors.forename: Antonio
authors.initials: A
authors.lastname: Neri
authors.affiliation: Nigeria Mission, Médecins Sans Frontières, Sokoto, Nigeria; Institute of Social and Cultural Anthropology, University of Oxford, Oxford, United Kingdom.
authors.forename: Darryl
authors.initials: D
authors.lastname: Stellmach
authors.affiliation: Department of Public Health, Federal Ministry of Health, Abuja, Nigeria.
authors.forename: Nasir
authors.initials: N
authors.lastname: Sani-Gwarzo
authors.affiliation: Nigeria Centre for Disease Control, Abuja, Nigeria.
authors.forename: Abdulsalami
authors.initials: A
authors.lastname: Nasidi
authors.affiliation: Public Health Department, Médecins Sans Frontières, Amsterdam, The Netherlands.
authors.forename: Leslie
authors.initials: L
authors.lastname: Shanks
authors.affiliation: Public Health Department, Médecins Sans Frontières, Amsterdam, The Netherlands; Guys and St. Thomas' NHS Foundation Trust and King's College London, London, United Kingdom.
authors.forename: Paul I
authors.initials: PI
authors.lastname: Dargan
mesh_terms: D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood*; D007855:Lead Poisoning / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D016015:Logistic Models; D008288:Malaria / Q000150:complications; D020258:Neurotoxicity Syndromes / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D009549:Nigeria; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D007854:Lead
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