title: Spatial analysis of gastroschisis in Massachusetts and Texas.
abstract: OBJECTIVE
  Previous research has suggested gastroschisis, a congenital malformation, may be linked to environmental or infectious factors and cases can occur in clusters. The objective of this study was to identify geographic areas of elevated gastroschisis risk.
  
  
  METHODS
  Cases of gastroschisis were identified from birth defect registries in Massachusetts and Texas. Random samples of live births were selected as controls. Generalized additive models were used to create a continuous map surface of odds ratios (ORs) by smoothing over latitude and longitude. Maternal age, race/ethnicity, education, cigarette smoking, and insurance status (MA only) were assessed for confounding. We used permutation tests to identify statistically significant areas of increased risk.
  
  
  RESULTS
  An area of increased risk was identified in North Central Massachusetts but was not significant after adjustment (P value = .07; OR = 2.0). In Texas, two statistically significant areas of increased risk were identified after adjustment (P value = .02; OR = 1.3 and 1.2). Texas had sufficient data to assess the combination of space and time, which identified an increased risk in 2003 and 2004.
  
  
  CONCLUSIONS
  This study suggests there were areas of elevated gastroschisis risk in Massachusetts and Texas, which cannot be explained by the risk factors we assessed. Additional exploration of underlying artifactual, environmental, infectious, or behavioral factors may further our understanding of gastroschisis.
authors.affiliation: Slone Epidemiology Center at Boston University, Boston, MA. Electronic address: Mahsa.Yazdy@channing.harvard.edu.
authors.forename: Mahsa M
authors.initials: MM
authors.lastname: Yazdy
authors.affiliation: Slone Epidemiology Center at Boston University, Boston, MA.
authors.forename: Martha M
authors.initials: MM
authors.lastname: Werler
authors.affiliation: Massachusetts Department of Public Health, Boston.
authors.forename: Marlene
authors.initials: M
authors.lastname: Anderka
authors.affiliation: Texas Department of State Health Services, Austin.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Langlois
authors.affiliation: Program in Public Health, University of California, Irvine.
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Vieira
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D020139:Gastroschisis / Q000453:epidemiology*; D040362:Geographic Information Systems; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008423:Maternal Age; D015233:Models, Statistical; D016017:Odds Ratio; D011159:Population Surveillance; D011247:Pregnancy; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D012959:Socioeconomic Factors; D062211:Spatio-Temporal Analysis; D013781:Texas / Q000453:epidemiology; D055815:Young Adult
keywords: Congenital abnormalities; Gastroschisis; Spatial analysis; Spatio-temporal analysis