Childhood attention-deficit/hyperactivity disorder symptoms are risk factors for obesity and physical inactivity in adolescence.

Objective: To prospectively investigate the association and directionality between attention-deficit/hyperactivity disorder (ADHD) symptoms and obesity from childhood to adolescence in the general population. We examined whether obesogenic behaviors, namely, physical inactivity and binge eating, underlie the potential ADHD symptom-obesity association. We explored whether childhood conduct disorder (CD) symptoms are related to adolescent obesity/physical inactivity.

Method: At 7 to 8 years (n = 8,106), teachers reported ADHD and CD symptoms, and parents reported body mass index (BMI) and physically active play. At 16 years (n = 6,934), parents reported ADHD symptoms; adolescents reported physical activity (transformed to metabolic equivalent of task [MET] hours per week) and binge eating; BMI and waist-hip ratio (WHR) were measured via clinical examination. Obesity was defined using the International Obesity Task Force (IOTF) cut-offs for BMI and the 95th percentile cut-off for WHR.

Results: Childhood ADHD symptoms significantly predicted adolescent obesity, rather than the opposite. Inattention-hyperactivity symptoms at 8 years were associated with indices of obesity at 16 years (obese BMI: odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.10-3.33; 95th percentile WHR: OR = 1.71, 95% CI = 1.05-2.78), adjusted for gender, baseline BMI, physical activity, family structure change, and maternal education. Child CD symptoms associated with indices of adolescent obesity. Reduced physically active play in childhood predicted adolescent inattention (OR = 1.61, 95% CI = 1.16-2.24). Childhood ADHD and CD symptoms were linked with physical inactivity in adolescence (inattention-hyperactivity; OR = 1.60, 95% CI = 1.20-2.13), but not binge eating. Physical inactivity mediated the associations.

Conclusions: Children with ADHD or CD symptoms are at increased risk for becoming obese and physically inactive adolescents. Physical activity may be beneficial for both behavior problems and obesity.