title: [Spatial distribution of birth defects among children aged 0 to 5 years and its relationship with soil chemical elements in Chongqing].
abstract: OBJECTIVE
  To explore the correlation between the incidence of birth defects and the contents of soil elements so as to provide a scientific basis for screening the related pathogenic factors that inducing birth defects for the development of related preventive and control strategies.
  
  
  METHODS
  MapInfo 7.0 software was used to draw the maps on spatial distribution regarding the incidence rates of birth defects and the contents of 11 chemical elements in soil in the 33 studied areas. Variables on the two maps were superposed for analyzing the spatial correlation. SAS 8.0 software was used to analyze single factor, multi-factors and principal components as well as to comprehensively evaluate the degrees of relevance.
  
  
  RESULTS
  Different incidence rates of birth defects showed in the maps of spatial distribution presented certain degrees of negative correlation with anomalies of soil chemical elements, including copper, chrome, iodine, selenium, zinc while positively correlated with the levels of lead. Results from the principal component regression equation indicating that the contents of copper(0.002), arsenic(-0.07), cadmium(0.05), chrome (-0.001), zinc (0.001), iodine(-0.03), lead (0.08), fluorine(-0.002)might serve as important factors that related to the prevalence of birth defects.
  
  
  CONCLUSIONS
  Through the study on spatial distribution, we noticed that the incidence rates of birth defects were related to the contents of copper, chrome, iodine, selenium, zinc, lead in soil while the contents of chrome, iodine and lead might lead to the occurrence of birth defects.
authors.affiliation: Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China. Email: zzhlxb@qq.com.
authors.forename: Zhao-hui
authors.initials: ZH
authors.lastname: Zhong
authors.affiliation: Institute of Science and Technology for Population and Family Planning.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Science and Technology for Population and Family Planning.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Faculty of Basic Medical Sciences.
authors.forename: Ying-xiong
authors.initials: YX
authors.lastname: Wang
authors.affiliation: Department of Statistics, School of Public Health and Management, Chongqing Medical University.
authors.forename: Bin
authors.initials: B
authors.lastname: Peng
authors.affiliation: Bureau of Gedogical Prospecting,Geological Brigade in Southeast of Sichuan.
authors.forename: Mao-zhong
authors.initials: MZ
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Ju
authors.initials: J
authors.lastname: Yan
authors.affiliation: Department of Statistics, School of Public Health and Management, Chongqing Medical University.
authors.forename: Fei-long
authors.initials: FL
authors.lastname: Xu
mesh_terms: D002675:Child, Preschool; D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000517:prevention & control; D004784:Environmental Monitoring; D005843:Geography; D006801:Humans; D015995:Prevalence; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil