title: Epidemiology of nonsyndromic conotruncal heart defects in Texas, 1999-2004.
abstract: BACKGROUND
  Congenital heart defects (CHDs) are the most common structural birth defects, yet their etiology is poorly understood. As there is heterogeneity within the group of CHDs, epidemiologic studies often focus on subgroups, of conditions, such as conotruncal heart defects (CTDs). However, even within these subgroups there may be etiologic heterogeneity. The aim of the present study was to identify and compare maternal and infant characteristics associated with three CTDs: truncus arteriosus (TA), dextro-transposition of the great arteries (d-TGA), and tetralogy of Fallot (TOF).
  
  
  METHODS
  Data for cases with nonsyndromic TA (n = 78), d-TGA (n = 438), and TOF (n = 529) from the Texas Birth Defects Registry, 1999-2004, were used to estimate crude and adjusted prevalence ratios, separately for each condition, using Poisson regression. Polytomous logistic regression was used to determine whether the observed associations were similar across the two largest case groups (d-TGA and TOF).
  
  
  RESULTS
  In Texas, 1999-2004, the prevalence of nonsyndromic TA, d-TGA, and TOF was 0.35, 1.98, and 2.40 per 10,000 live births, respectively. There was evidence of a significant linear increase in the risk of each condition with advancing maternal age (p < 0.01). Significant associations were observed for TA and maternal residence on the Texas-Mexico border; d-TGA and infant sex, maternal race/ethnicity, history of previous live birth, and birth year; and TOF and maternal race/ethnicity and education. Further, the associations with some, but not all, of the study variables were significantly different for d-TGA and TOF.
  
  
  CONCLUSIONS
  These findings add to our limited understanding of the epidemiology of CTDs.
authors.affiliation: Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77382, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Long
authors.forename: Tunu
authors.initials: T
authors.lastname: Ramadhani
authors.forename: Laura E
authors.initials: LE
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D005260:Female; D006330:Heart Defects, Congenital / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth / Q000453:epidemiology; D008297:Male; D008423:Maternal Age; D008800:Mexico / Q000453:epidemiology; D011247:Pregnancy; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D013771:Tetralogy of Fallot / Q000453:epidemiology / Q000209:etiology; D013781:Texas / Q000453:epidemiology; D014188:Transposition of Great Vessels / Q000453:epidemiology / Q000209:etiology; D014339:Truncus Arteriosus, Persistent / Q000453:epidemiology / Q000209:etiology; D055815:Young Adult