Moderating Effects Of ADHD On Associations Between Fitness, Body Composition, And Academic Outcomes In Children

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is highly prevalent (9.4%) among US children and impacts their learning processes. Previous work has identified associations between aerobic fitness, body composition, and academic achievement outcomes in children, including those with ADHD. Yet, many individual differences among these pediatric samples likely moderate these effects. PURPOSE: Examine the moderating role of ADHD on the associations between aerobic fitness, body composition, and academic achievement outcomes. METHODS: Cross-sectional data was collected in a sample of 6-16 year old children (N = 59; age = 9.95 士 2.84 years). Correlations and moderation analyses were conducted on academic achievement outcomes from the Woodcock Johnson IV as dependent variables. Independent variables included body composition measures of lean body mass (LBM) and visceral fat area (VFA), obtained via bioelectric impedance analysis; and fat-free aerobic fitness (ml/kg(lean)/min) obtained via a graded treadmill VO2 protocol, and calculated using VO2peak (ml/kg/min) with LBM (lean kg). ADHD percentile, obtained via the ADHD Rating Scale IV, was used as the moderator variable. RESULTS: Fat-free VO2 was positively correlated with reading (r = .35, p = .00), yet ADHD percentile was negatively correlated with passage comprehension (r = -.32, p = .01). The association between fat-free fitness and reading performance was significantly moderated by ADHD percentile (R2 = .14, F(3, 51) = 2.87, p = .04). Similarly, the association between LBM and reading was moderated by ADHD percentile (R2 = .19, F(3, 52) = 4.27, p = .00). Lastly, the associations between VFA and letter word identification (R2 = .17, F(3, 52) = 3.70, p = .01), passage comprehension (R2 = .18, F(3, 51) = 3.84, p = .01), and word attack (R2 = .16, F(3, 50) = 3.27, p = .02) were significantly moderated by ADHD percentile. CONCLUSIONS: Our findings suggest that ADHD may amplify the associations of physical health on academic performance. As children with ADHD experience difficulty in school environments, future research should investigate potential mechanisms, such as physical activity, to support academic success and to improve aerobic fitness, reduce fat mass, and/or increase lean mass. Supported by: Rhode Island Foundation Medical Research Grant