title: Predictors of trisomy 21 in the offspring of older and younger women.
abstract: BACKGROUND
  Advanced maternal age is the only well-established risk factor for trisomy 21, yet the majority of affected individuals are born to younger women. To identify factors associated with the risk of trisomy 21 in the offspring of younger and older women, we analyzed data for cases with trisomy 21 from the Texas Birth Defects Registry for 1999 to 2007.
  
  
  METHODS
  Data were analyzed separately for younger (i.e., <35 years of age at delivery; n = 2306) and older (i.e., ≥ 35 years of age at delivery; n = 1811) women using Poisson regression.
  
  
  RESULTS
  After adjustment for maternal age and several other covariates, the prevalence of trisomy 21 in the offspring of women in both maternal age groups was higher in male than in female infants and in offspring of women who were Hispanic (compared with non-Hispanic white women) or who had at least one previous liveborn child compared to those with none. In the offspring of older women only, the prevalence of trisomy 21 was also significantly higher when the father was 20 to 24 years old (compared with 25 to 29 years old; adjusted prevalence ratio [aPR], 2.27; 95% confidence interval [CI], 1.47-3.49) and Hispanic (compared with non-Hispanic white; aPR, 1.34; 95% CI, 1.13-1.58) and among women with less than a high school education (compared with greater than high school).
  
  
  CONCLUSIONS
  This study identified several factors, in addition to maternal age, that were associated with trisomy 21 risk. In general, these factors were similar for both maternal age groups, although paternal characteristics were significantly associated with risk of trisomy 21 only in offspring of older women.
authors: Center for Human Genetics, Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, Houston, Texas, USA.
authors: A J
authors: AJ
authors: Agopian
authors: Lisa K
authors: LK
authors: Marengo
authors: Laura E
authors: LE
authors: Mitchell
mesh_terms: D000328:Adult; D000013:Congenital Abnormalities; D004314:Down Syndrome / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D008423:Maternal Age; D010331:Paternal Age; D015995:Prevalence; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology / Q000208:ethnology; D055815:Young Adult