title: Prenatal lead exposure and fetal growth: Smaller infants have heightened susceptibility.
abstract: As population lead levels decrease, the toxic effects of lead may be distributed to more sensitive populations, such as infants with poor fetal growth.
  
  
  
  To determine the association of prenatal lead exposure and fetal growth; and to evaluate whether infants with poor fetal growth are more susceptible to lead toxicity than those with normal fetal growth.
  
  
  
  We examined the association of second trimester maternal blood lead levels (BLL) with birthweight-for-gestational age (BWGA) z-score in 944 mother-infant participants of the PROGRESS cohort. We determined the association between maternal BLL and BWGA z-score by using both linear and quantile regression. We estimated odds ratios for small-for-gestational age (SGA) infants between maternal BLL quartiles using logistic regression. Maternal age, body mass index, socioeconomic status, parity, household smoking exposure, hemoglobin levels, and infant sex were included as confounders.
  
  
  
  While linear regression showed a negative association between maternal BLL and BWGA z-score (β=-0.06 z-score units per log2BLL increase; 95% CI: -0.13, 0.003; P=0.06), quantile regression revealed larger magnitudes of this association in the <30th percentiles of BWGA z-score (β range [-0.08, -0.13] z-score units per log2BLL increase; all P values<0.05). Mothers in the highest BLL quartile had an odds ratio of 1.62 (95% CI: 0.99-2.65) for having a SGA infant compared to the lowest BLL quartile.
  
  
  
  While both linear and quantile regression showed a negative association between prenatal lead exposure and birthweight, quantile regression revealed that smaller infants may represent a more susceptible subpopulation.
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: rrodosth@hsph.harvard.edu.
authors.forename: Rodosthenis S
authors.initials: RS
authors.lastname: Rodosthenous
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Neonatology, Beth Israel Deaconess Medical Center and Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA. Electronic address: heburris@bidmc.harvard.edu.
authors.forename: Heather H
authors.initials: HH
authors.lastname: Burris
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address: Katherine.svensson@mssm.edu.
authors.forename: Katherine
authors.initials: K
authors.lastname: Svensson
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address: Chitra.amarasiriwardena@mssm.edu.
authors.forename: Chitra J
authors.initials: CJ
authors.lastname: Amarasiriwardena
authors.affiliation: Division of Research in Community Interventions, National Institute of Perinatology, Mexico City, Mexico. Electronic address: alejandra.cantoral@insp.mx.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Cantoral
authors.affiliation: Division of Research in Community Interventions, National Institute of Perinatology, Mexico City, Mexico. Electronic address: lschnaas@hotmail.com.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Schnaas
authors.affiliation: Division of Research in Community Interventions, National Institute of Perinatology, Mexico City, Mexico. Electronic address: adrianam@insp.mx.
authors.forename: Adriana
authors.initials: A
authors.lastname: Mercado-García
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: bcoull@hsph.harvard.edu.
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address: Robert.wright@mssm.edu.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Wright
authors.affiliation: Division of Research in Community Interventions, National Institute of Perinatology, Mexico City, Mexico. Electronic address: mmtellez@insp.mx.
authors.forename: Martha M
authors.initials: MM
authors.lastname: Téllez-Rojo
authors.affiliation: Laboratory of Precision Environmental Biosciences, Columbia University Mailman School of Public Health, New York, NY, USA. Electronic address: andrea.baccarelli@columbia.edu.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D005865:Gestational Age; D006801:Humans; D007236:Infant, Small for Gestational Age; D007854:Lead / Q000633:toxicity*; D008297:Male; D018811:Maternal Exposure; D008800:Mexico; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012306:Risk; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D007854:Lead
keywords: Birth weight; Fetal growth; Lead; Pregnancy; Quantile regression; Small-for-gestational age