Researchers at Mayo Clinic, Rochester, MN, and Children's Hospital Boston, MA evaluated the incidence rates of written-language disorder (WLD), with and without reading disability (RD), according to gender, among children with and without attention deficit hyperactivity disorder (ADHD) in a population-based birth cohort. The cumulative incidence of'WLD by 19 years of age was significantly higher for children with ADHD than for children without ADHD, for both boys and girls (boys: 64.5% vs 16.5%; girls: 57.0% vs 9.4%). In contrast, among children without ADHD, the cumulative incidences of WLD were higher for boys than girls (boys: 16.5%; girls: 9.4%). Subjects with ADHD were more likely to be male, to be white, to have mothers with fewer years of education, and to have younger mothers at birth compared with subjects without ADHD. Perinatal factors were not different among children with and without ADHD in this cohort.
ADHD was significantly associated with an increased risk of WLD with RD for both boys and girls. However, the magnitude of increased risk for WLD associated with ADHD was significantly greater for girls than for boys (hazard ratio: girls: 9.8; boys: 4.2; p< .001). Without RD, boys and girls are at the same risk of having WLD (hazard ratio: girls: 7.4; boys: 8.6; p= .64). 
COMMENT. In a Rochester-Olmsted County, MN-based cohort of children, ADHD is associated with an increased risk of WLD for both boys and girls. The risk of WLD with RD associated with ADHD is higher in girls than in boys. In ADHD children having WLD without RD, boys and girls are at the same risk of having WLD. Neuropsychological evaluation of children with ADHD should include tests for written language and reading. The AAP recommends tests for coexisting conditions in children with ADHD. Regrettably, the availability of such evaluations for LD in many US school populations is drastically diminished in recent months, and specific remedial education for LD and RD in public schools is often wanting.