title: A nested case-control study indicating heavy metal residues in meconium associate with maternal gestational diabetes mellitus risk.
abstract: BACKGROUND
  Environmental pollutant exposure may play certain roles in the pathogenesis and progression of diabetes mellitus including gestational diabetes mellitus (GDM). We hypothesize that heavy metal exposure may trigger GDM during pregnancy. The objective of this study was to investigate the possible associations between selected heavy metal exposure and GDM risk.
  
  
  METHODS
  This investigation is a retrospective case-control study nested within a cohort of 1359 pregnant women. These participants were recruited in Xiamen Maternity and Child Care Hospital, China, during June to July, 2012. All their newborns' meconium samples were collected. By reviewing the antenatal care records, 166 GDM mothers were screened out from the 1359 participants; 137 of 166 GDM mothers offered their newborns' meconium samples for the metal analysis. Those 137 mothers were set as the case group. Similarly, 294 healthy mothers without any gestational complication were initially screened out from the rest 1193 non-GDM mothers. 190 of the 294 healthy mothers offered their newborns' meconium samples for the metal analysis. Those 190 mothers were set as the control group. Arsenic (As), mercury (Hg), lead (Pb), cadmium (Cd), and chromium (Cr) levels in these case-control meconium samples were measured by inductively coupled plasma mass spectrometry. The possible association between the metal levels and maternal GDM risk of studied subjects was assessed by binary logistic regression.
  
  
  RESULTS
  GDM prevalence of 12.21% was observed in the investigated 1359 participants. The concentrations of As, Hg, Cr and Cd in studied cases were significantly higher (p < 0.05) than those of controls. After adjustments for maternal age, pre-pregnant body mass index, gravidity, parity, hepatitis B virus infection, and newborn sex, As, Cd and Cr were found to be positively associated with GDM prevalence in dose-dependent manners. Among them, As was detected in all samples and its levels associated the maternal GDM with the adjusted odds ratios of 3.28 [95% CI 1.24, 8.71], 3.35 [95% CI 1.28, 8.75] and 5.25 [95% CI 1.99, 13.86] for the 2(nd), 3(rd) and 4(th) quartiles, respectively.
  
  
  CONCLUSIONS
  The present work implies that exposure to some of the selected metals (noticeably As) may contribute to maternal GDM risk during pregnancy.
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. sypeng@iue.ac.cn.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Peng
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. lpliu@iue.ac.cn.
authors.forename: Liangpo
authors.initials: L
authors.lastname: Liu
authors.affiliation: Xiamen Maternity and Child Health Care Hospital, Xiamen, 361003, PR China. wind459@126.com.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institutfür Epidemiologie I, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany. joachim.heinrich@helmholtz-muenchen.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Heinrich
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. jzhang@iue.ac.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Molecular EXposomics (MEX), Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstr.1, 85764, Neuherberg, Germany. schramm@helmholtz-muenchen.de.|Department für Biowissenschaftliche Grundlagen, Technische Universität München, Weihenstephaner Steig 23, 85350, Freising, Germany. schramm@helmholtz-muenchen.de.
authors.forename: Karl-Werner
authors.initials: KW
authors.lastname: Schramm
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. qyhuang@iue.ac.cn.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. mptian@iue.ac.cn.
authors.forename: Meiping
authors.initials: M
authors.lastname: Tian
authors.affiliation: Public Health and Environment Division, Department of Biosciences, COMSATS Institute of Information and Technology, Islamabad, Pakistan. ali_ebl2@yahoo.com.
authors.forename: Syed Ali Musstjab Akber Shah
authors.initials: SA
authors.lastname: Eqani
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China. hqshen@iue.ac.cn.
authors.forename: Heqing
authors.initials: H
authors.lastname: Shen
mesh_terms: D000328:Adult; D001151:Arsenic / Q000633:toxicity*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000139:chemically induced / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D018811:Maternal Exposure; D008470:Meconium / Q000737:chemistry*; D019216:Metals, Heavy / Q000633:toxicity*; D011247:Pregnancy; D012189:Retrospective Studies; D018570:Risk Assessment; D055815:Young Adult
chemical_list: D019216:Metals, Heavy; D001151:Arsenic