title: Gender, attention-deficit/hyperactivity disorder, and reading disability in a population-based birth cohort.
abstract: OBJECTIVE
  To determine the incidence of reading disability (RD) among children with and without research-identified attention-deficit/hyperactivity disorder (ADHD), separately according to gender, in a population-based birth cohort.
  
  
  METHODS
  Subjects included all children born in 1976-1982 remaining in Rochester, Minnesota, after 5 years of age (n=5718). Information from medical, school, and private tutorial records was abstracted. Cumulative incidence of RD, by any of 3 RD formulas, in children with and without ADHD and corresponding hazard ratios (HRs) were calculated separately according to gender.
  
  
  RESULTS
  Cumulative incidence of RD by the age of 19 years was significantly higher in children with ADHD (51% in boys, 46.7% in girls) compared with those without ADHD (14.5% in boys, 7.7% in girls). Among children with ADHD, the risk for RD was similar in boys versus girls (HR: 1.0). However, among children without ADHD, boys were 2.0 times more likely than girls to meet RD criteria. Among girls, the HR for the risk for RD associated with ADHD (versus those without ADHD) was 8.1 (95% confidence interval: 5.7-11.5), which was significantly higher than the corresponding HR among boys (3.9 [95% confidence interval: 3.2-4.9]).
  
  
  CONCLUSIONS
  The risk for RD is significantly greater among children with ADHD compared with those without ADHD. Among children with ADHD, the risk for RD is the same for boys and girls. However, among children without ADHD, boys are more at risk for RD than girls. Among girls, the magnitude of increased risk for RD associated with ADHD is nearly twice that among boys, because girls without ADHD are less likely to have RD than boys without ADHD.
authors.affiliation: Division of Epidemiology, Department of Health Science Research, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. kyoshi@wakayama-med.ac.jp
authors.forename: Kouichi
authors.initials: K
authors.lastname: Yoshimasu
authors.forename: William J
authors.initials: WJ
authors.lastname: Barbaresi
authors.forename: Robert C
authors.initials: RC
authors.lastname: Colligan
authors.forename: Jill M
authors.initials: JM
authors.lastname: Killian
authors.forename: Robert G
authors.initials: RG
authors.lastname: Voigt
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weaver
authors.forename: Slavica K
authors.initials: SK
authors.lastname: Katusic
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications*; D002648:Child; D015331:Cohort Studies; D004410:Dyslexia / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D017678:Sex Distribution; D012959:Socioeconomic Factors