title: Comparison of urinary aflatoxin M1 and aflatoxin albumin adducts as biomarkers for assessing aflatoxin exposure in Tanzanian children.
abstract: OBJECTIVE
  To determine levels of urinary aflatoxin M1 (AFM1) in children and correlate the concentrations with previously reported aflatoxin albumin adduct (AF-alb) levels in these children.
  
  
  METHODS
  Matched urine and blood samples were collected from 84 Tanzanian children aged 6-14 months old. From 31 children in one village (Kigwa), samples were collected at three time points six months apart. Samples were collected from 31 and 22 children from two different regions at the second time point only. Urinary AFM1 was measured using a commercial enzyme-linked immunosorbent assay (ELISA) kit with a modified protocol to improve sensitivity. AF-alb was measured using an established ELISA method.
  
  
  RESULTS
  The relative ranking of the three villages for exposure to aflatoxin based on either AFM1or AF-alb biomarker measurements was the same. In Kigwa village, both AFM1 and AF-alb levels were higher at six months post-harvest compared to baseline. However, at the next visit, the AFM1 levels dropped from a GM (interquartile range) of 71.0 (44.7, 112.6) at visit two to 49.3 (31.5, 77.3) pg/ml urine, whereas AF-alb levels increased from 47.3 (29.7, 75.2) to 52.7 (35.4, 78.3) pg/mg albumin between these two visits, reflecting the fact that AFM1 measures short-term exposure, whereas AF-alb measures longer term exposure. There was a correlation between AFB1 intake and AFM1 excretion (r= 0.442, p ≤ 0.001).
  
  
  CONCLUSIONS
  Urinary AFM1 is a good biomarker for AFB1 exposure in Tanzanian children, reflecting geographical and temporal variations in exposure to this foodborne toxin.
authors.affiliation: a Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast , Belfast , United Kingdom.
authors.forename: Gaoyun
authors.initials: G
authors.lastname: Chen
authors.affiliation: a Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast , Belfast , United Kingdom.|b School of Food Science and Nutrition, University of Leeds , Leeds , United Kingdom.
authors.forename: Yun Yun
authors.initials: YY
authors.lastname: Gong
authors.affiliation: c The Nelson Mandela Institution of Science and Technology, School of Life Sciences and Bioengineering , Arusha , Tanzania.
authors.forename: Martin E
authors.identifier: http://orcid.org/0000-0002-8320-2841
authors.initials: ME
authors.lastname: Kimanya
authors.affiliation: d Tanzania Food and Drugs Authority , Dar es Salaam , Tanzania.
authors.forename: Candida P
authors.initials: CP
authors.lastname: Shirima
authors.affiliation: e LICAMM , School of Medicine, University of Leeds , Leeds, United Kingdom.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Routledge
mesh_terms: D016607:Aflatoxin M1 / Q000097:blood / Q000652:urine*; D000348:Aflatoxins / Q000097:blood / Q000652:urine*; D000418:Albumins; D015415:Biomarkers / Q000097:blood / Q000652:urine*; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007223:Infant; D013636:Tanzania; D003313:Zea mays
chemical_list: D000348:Aflatoxins; D000418:Albumins; D015415:Biomarkers; C098408:aflatoxin-albumin adduct; D016607:Aflatoxin M1
keywords: Aflatoxins; Tanzania; aflatoxin albumin adducts; children; urinary AFM1