title: Arsenic exposure affects plasma insulin-like growth factor 1 (IGF-1) in children in rural Bangladesh.
abstract: BACKGROUND
  Exposure to inorganic arsenic (As) through drinking water during pregnancy is associated with lower birth size and child growth. The aim of the study was to assess the effects of As exposure on child growth parameters to evaluate causal associations.
  
  
  RESULTS
  Children born in a longitudinal mother-child cohort in rural Bangladesh were studied at 4.5 years (n=640) as well as at birth (n=134). Exposure to arsenic was assessed by concurrent and prenatal (maternal) urinary concentrations of arsenic metabolites (U-As). Associations with plasma concentrations of insulin-like growth factor 1 (IGF-1), calcium (Ca), vitamin D (Vit-D), bone-specific alkaline phosphatase (B-ALP), intact parathyroid hormone (iPTH), and phosphate (PO4) were evaluated by linear regression analysis, adjusted for socioeconomic factor, parity and child sex. Child U-As (per 10 µg/L) was significantly inversely associated with concurrent plasma IGF-1 (β=-0.27; 95% confidence interval: -0.50, -0.0042) at 4.5 years. The effect was more obvious in girls (β=-0.29; -0.59, 0.021) than in boys, and particularly in girls with adequate height (β=-0.491; -0.97, -0.02) or weight (β=-0.47; 0.97, 0.01). Maternal U-As was inversely associated with child IGF-1 at birth (r=-0.254, P=0.003), but not at 4.5 years. There was a tendency of positive association between U-As and plasma PO4 in stunted boys (β=0.27; 0.089, 0.46). When stratified by % monomethylarsonic acid (MMA, arsenic metabolite) (median split at 9.7%), a much stronger inverse association between U-As and IGF-1 in the girls (β=-0.41; -0.77, -0.03) was obtained above the median split.
  
  
  CONCLUSIONS
  The results suggest that As-related growth impairment in children is mediated, at least partly, through suppressed IGF-1 levels.
authors.affiliation: Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh ; Institute of Environmental Medicine (IMM), Karolinska Institutet, Stockholm, Sweden.
authors.forename: Sultan
authors.initials: S
authors.lastname: Ahmed
authors.forename: Rokeya Sultana
authors.initials: RS
authors.lastname: Rekha
authors.forename: Khalid Bin
authors.initials: KB
authors.lastname: Ahsan
authors.forename: Mariko
authors.initials: M
authors.lastname: Doi
authors.forename: Margaretha
authors.initials: M
authors.lastname: Grandér
authors.forename: Anjan Kumar
authors.initials: AK
authors.lastname: Roy
authors.forename: Eva-Charlotte
authors.initials: EC
authors.lastname: Ekström
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Wagatsuma
authors.forename: Marie
authors.initials: M
authors.lastname: Vahter
authors.forename: Rubhana
authors.initials: R
authors.lastname: Raqib
mesh_terms: D000293:Adolescent; D001151:Arsenic / Q000009:adverse effects*; D001459:Bangladesh; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D062486:Public Health Surveillance; D012424:Rural Population
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I; D001151:Arsenic