title: A Case-Control Study of Prenatal Thallium Exposure and Low Birth Weight in China.
abstract: BACKGROUND
  Thallium (Tl) is a highly toxic heavy metal widely present in the environment. Case reports have suggested that maternal exposure to high levels of Tl during pregnancy is associated with low birth weight (LBW), but epidemiological data are limited.
  
  
  OBJECTIVE
  This study was designed to evaluate whether prenatal Tl exposure is associated with an increased risk of LBW.
  
  
  METHODS
  This case-control study involving 816 study participants (204 LBW cases and 612 matched controls) was conducted in Hubei Province, China, in 2012-2014. Tl concentrations were measured in maternal urine collected at delivery, and associations with LBW were evaluated using conditional logistic regression.
  
  
  RESULTS
  Higher maternal urinary Tl levels were significantly associated with increased risk of LBW [crude odds ratio (OR) = 1.52; 95% CI: 1.00, 2.30 for the highest vs. lowest tertile], and the association was similarly elevated after adjustment for potential confounders (adjusted OR = 1.90; 95% CI: 1.01, 3.58 for the highest vs. lowest tertile). Stratified analyses showed slightly higher risk estimates for LBW associated with higher Tl levels for mothers < 28 years old and for mothers with lower household income; however, there was no statistical evidence of heterogeneity in risk according to maternal age (p for heterogeneity = 0.18) or household income (p for heterogeneity = 0.28).
  
  
  CONCLUSIONS
  To our knowledge, ours is the first case-control study to investigate the association between prenatal Tl exposure and LBW. The results suggest that prenatal exposure to high levels of Tl may be associated with an increased risk of LBW.
  
  
  BACKGROUND
  Xia W, Du X, Zheng T, Zhang B, Li Y, Bassig BA, Zhou A, Wang Y, Xiong C, Li Z, Yao Y, Hu J, Zhou Y, Liu J, Xue W, Ma Y, Pan X, Peng Y, Xu S. 2016. A case-control study of prenatal thallium exposure and low birth weight in China. Environ Health Perspect 124:164-169; http://dx.doi.org/10.1289/ehp.1409202.
authors.affiliation: Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xia
authors.forename: Xiaofu
authors.initials: X
authors.lastname: Du
authors.forename: Tongzhang
authors.initials: T
authors.lastname: Zheng
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Li
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Bassig
authors.forename: Aifen
authors.initials: A
authors.lastname: Zhou
authors.forename: Youjie
authors.initials: Y
authors.lastname: Wang
authors.forename: Chao
authors.initials: C
authors.lastname: Xiong
authors.forename: Zhengkuan
authors.initials: Z
authors.lastname: Li
authors.forename: Yuanxiang
authors.initials: Y
authors.lastname: Yao
authors.forename: Jie
authors.initials: J
authors.lastname: Hu
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Weiyan
authors.initials: W
authors.lastname: Xue
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Xinyun
authors.initials: X
authors.lastname: Pan
authors.forename: Yang
authors.initials: Y
authors.lastname: Peng
authors.forename: Shunqing
authors.initials: S
authors.lastname: Xu
mesh_terms: D016022:Case-Control Studies; D002681:China; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D016015:Logistic Models; D018811:Maternal Exposure / Q000009:adverse effects; D011247:Pregnancy; D013793:Thallium / Q000633:toxicity*
chemical_list: D013793:Thallium