ADHD more likely in preschoolers with lazy eye; impaired fine motor skill a mediator

Amblyopic children are at an increased risk of attention-deficit/hyperactivity disorder (ADHD), reports a recent Korea study. Deficits in the development of fine motor skills may contribute to such a correlation.

The propensity score-matched analysis study included 7,762 amblyopic children and 31,030 healthy controls. The primary outcomes were ADHD and autism spectrum disorder (ASD), as defined by the 10th revision of the International Classification of Diseases. Developmental problems, assessed using the Korean Ages and Stages Questionnaire (K-ASQ), were set as the secondary outcome.

Regression analysis revealed that amblyopia was significantly and positively associated with ADHD (odds ratio [OR], 1.687, 95 percent confidence interval [CI], 1.444–1.970), but not with ASD (OR, 0.591, 95 percent CI, 0.341–1.026).

Mediation analysis taking K-ASQ results into account revealed a significant correlation between impaired fine motor skills and ADHD (adjusted OR, 1.38, 95 percent CI, 1.10–1.66). In particular, ADHD had an incidence proportion of 12.01 percent in boys with fine motor skill impairment, as opposed to only 4.45 percent in those without. The resulting absolute risk of 7.56 percent was statistically significant (95 percent CI, 6.14–8.98).

A similar effect was reported in girls, in whom fine motor skill impairment was also significantly correlated with ADHD (adjusted OR, 1.73, 95 percent CI, 1.05-2.40). The incidence proportion of ADHD was 3.97 percent and 0.98 percent in girls with and without impaired fine motor skills, respectively, yielding a significant absolute risk difference of 2.98 percent (95 percent CI, 1.97–3.99).

According to researchers, fine motor skill impairment, as a mediating factor, increased the incidence of ADHD in boys and girls by 4.6 percent and 2.6 percent, respectively.