title: Maternal exposure to ozone and PM2.5and the prevalence of orofacial clefts in four U.S. states.
abstract: BACKGROUND
  While there is some evidence that maternal exposure to ambient air pollution is associated with orofacial clefts in offspring, the epidemiologic studies have been largely equivocal. We evaluated whether maternal exposure to elevated county-level ambient fine particulate matter with aerodynamic diameter ≤2.5µm (PM2.5) and ozone during early gestation was associated with a higher prevalence of orofacial clefts.
  
  
  METHODS
  Birth data consisting of 4.7 million births from 2001 to 2007 were obtained from National Birth Defects Prevention Network for four states - Arizona, Florida, New York (excluding New York City), and Texas. The air pollution exposure assessment for gestational weeks 5-10 was based on county-level average concentrations of PM2.5and ozone data generated using a Bayesian fusion model available through CDC's Environmental Public Health Tracking Network. Two outcomes were analyzed separately: cleft lip with or without cleft palate, cleft palate alone. In logistic regression analyses, we adjusted for factors that were suspected confounders or modifiers of the association between the prevalence of orofacial clefts and air pollution, i.e., infant sex, race-ethnicity, maternal education, smoking status during pregnancy, whether this was mother's first baby, maternal age.
  
  
  RESULTS
  Each 10µg/m3increase in PM2.5concentration was significantly associated with cleft palate alone (OR =1.43, 95% CI: 1.11-1.86). There was no significant association between PM2.5concentration and cleft lip with or without cleft palate. No associations were observed between ozone exposure and the two outcomes of orofacial clefts.
  
  
  CONCLUSIONS
  Our study suggests that PM2.5significantly increased the risk of cleft palate alone, but did not change the incidence of cleft lip with or without palate. Ozone levels did not correlate with incidence of orofacial clefts.
authors.affiliation: Environmental Health Tracking Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. Electronic address: yzhou2@cdc.gov.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Birth Defects Branch, Division of Congenital and Developmental Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Gilboa
authors.affiliation: New York State Department of Health, Center for Environmental Health, Albany, NY, USA; State University of New York at Albany, Department of Epidemiology and Biostatistics, Rensselaer, NY, USA.
authors.forename: Michele L
authors.initials: ML
authors.lastname: Herdt
authors.affiliation: Baylor College of Medicine, Department of Pediatrics, Section of Hematology-Oncology, Houston, TX, USA.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Lupo
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
authors.forename: W Dana
authors.initials: WD
authors.lastname: Flanders
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Environmental Health Tracking Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Mikyong
authors.initials: M
authors.lastname: Shin
authors.affiliation: Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, TX, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Canfield
authors.affiliation: Department of Community and Family Health, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Russell S
authors.initials: RS
authors.lastname: Kirby
mesh_terms: D000293:Adolescent; D000328:Adult; D001130:Arizona / Q000453:epidemiology; D002971:Cleft Lip / Q000453:epidemiology* / Q000209:etiology; D002972:Cleft Palate / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005431:Florida / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D009518:New York / Q000453:epidemiology; D010126:Ozone / Q000009:adverse effects / Q000032:analysis; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology; D055815:Young Adult
chemical_list: D052638:Particulate Matter; D010126:Ozone
keywords: Air pollution; Cleft lip; Cleft palate; Ozone; PM(2.5)