title: Association between thyroxine levels at birth and choanal atresia or stenosis among infants in Texas, 2004-2007.
abstract: BACKGROUND
  The causes of choanal atresia or stenosis (CA) are largely unknown. Infant thyroxine (T(4) ) levels collected during newborn screening may be proxy measures for a risk factor present during the critical period of development. Therefore, we conducted a case-control study to examine the association between newborn T(4) levels and CA.
  
  
  METHODS
  Data for cases with CA and controls were obtained from the Texas Birth Defects Registry for the period of 2004 to 2007. Information on infant T(4) levels at birth was obtained from the Texas Newborn Screening Program. Controls (n = 3570) were drawn from unaffected births in Texas for the same period and frequency matched to cases (n = 69) on year of birth, then linked to the newborn screening database. Logistic regression was used to evaluate the association between continuous and categorical infant T(4) levels and nonsyndromic CA.
  
  
  RESULTS
  After adjustment for gestational age and year of birth, infant T(4) levels were inversely associated with CA (adjusted odds ratio [AOR], 0.85; 95% confidence interval [CI], 0.80-0.90). We observed a linear trend (p < 0.001) across quartiles of T(4) ; compared to infants with low levels, AORs for CA were 0.50 (95% CI, 0.28-0.91), 0.39 (95% CI, 0.20-0.75), and 0.15 (95% CI, 0.06-0.40) for infants with medium-to-low, medium, and high levels, respectively.
  
  
  CONCLUSIONS
  Our findings suggest a role of low thyroid hormone levels in the development of CA, or that low newborn T(4) levels are potential proxy measures of a risk factor present during the critical period. Birth Defects Research (Part A), 2012.
authors.affiliation: Human Genetics Center, Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, Houston, Texas, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Lee
authors.forename: Mark A
authors.initials: MA
authors.lastname: Canfield
authors.forename: S Shahrukh
authors.initials: SS
authors.lastname: Hashmi
authors.forename: Karen B
authors.initials: KB
authors.lastname: Moffitt
authors.forename: Lisa
authors.initials: L
authors.lastname: Marengo
authors.forename: A J
authors.initials: AJ
authors.lastname: Agopian
authors.forename: John W
authors.initials: JW
authors.lastname: Belmont
authors.forename: Debra
authors.initials: D
authors.lastname: Freedenberg
authors.forename: Susan M
authors.initials: SM
authors.lastname: Tanksley
authors.forename: Laura E
authors.initials: LE
authors.lastname: Mitchell
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Lupo
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002754:Choanal Atresia / Q000097:blood* / Q000453:epidemiology*; D003251:Constriction, Pathologic / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D015997:Neonatal Screening; D012042:Registries; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology; D013974:Thyroxine / Q000097:blood*
chemical_list: D015415:Biomarkers; D013974:Thyroxine