The association between attention deficit hyperactivity disorder severity and risk of mild traumatic brain injury in children with attention deficit hyperactivity disorder in the United States of America: A cross-sectional study of data from the National Survey of Children with Special Health Care Needs

Background: As children with attention deficit hyperactivity disorder (ADHD) have shown to be at higher risk of accidents and injury, one may assume that they may also bear a higher likelihood of mild traumatic brain injuries (mTBI). However, the current scientific evidence whether ADHD severity is associated with traumatic brain injuries is controversial. The objective of this study was too assess the association between the severity of ADHD and prevalence of mTBI in 0- to 18-year-old children with ADHD in the United States. Methods: Cross-sectional study using secondary data gathered in 2009/10 from the National Survey of Children with Special Healthcare Needs. After excluding comorbidity and those with nonspecific attention deficits, the final study population consisted of 10,739 children with ADHD from 40,052 households. The main exposure variable was self-reported ADHD severity (mild, moderate, or severe). The main outcome was mTBI, defined as head injury, traumatic brain injury, and/or concussion). Covariates included age, gender and race, medication status. Unadjusted and adjusted logistic regression analysis were used. Results: Children with more severe ADHD had consistently increased incidences of mTBI. Adjusted logistic regression analysis revealed a statistically significant association between severity of ADHD and occurrence of mTBI. The corresponding odds ratios were 1.57 (95% confidence interval (CI) [1.13, 2.18] for moderate, and 1.79 (95% CI [1.18, 2.72]) for severe ADHD, respectively, compared with mild ADHD. In males, children with moderate and severe ADHD had increased odds of mTBI. The corresponding odds ratio for mTBI in those with moderate ADHD was 1.60 (95% CI [1.07, 2.39]) and 1.86 (95% CI [1.15, 3.00]) for severe ADHD, respectively. No associations between severity and mTBI were found in girls. Conclusions: As ADHD severity was associated with incidence of mTBI, it is important to identify those who need increased attention and counselling to prevent injury.