Attention-Deficit Hyperactivity Disorder and Obesity - A Nationwide Study of 1.1 Million Israeli Adolescents

Background and aim: The incidences of obesity and attention-deficit/hyperactivity disorder (ADHD) have increased in parallel over recent decades. We aimed to assess the association between obesity and ADHD in a national sample of adolescents.

Method: This was a cross-sectional study of 1,118,315 adolescents (57% males; mean age 17 years). Risks of obesity were compared between individuals with severe and mild ADHD, and those without ADHD. Diagnoses of ADHD were confirmed by specialists in neurology or psychiatry according to psycho-didactic criteria. Adolescents requiring regular and continuous treatment with stimulants with no improvement of symptoms under treatment were classified as having severe ADHD (n=3,062); data were available from 2004 to 2019. Individuals with mild symptoms who required medications only for learning or who used stimulants irregularly were defined as having mild ADHD (n=65,118); data were available from 2015 to 2019.
Results: The prevalence of severe ADHD was 0.3% and of mild ADHD 20.1%. After adjustment for sex, birth year, age, height, place of birth and residential socioeconomic position, the odds ratios for obesity in the severe ADHD group were 1.77 (1.56-2.02) higher for males and 2.09 (1.63-2.66) for females than in the low-normal BMI (reference group), and for the mild ADHD group 1.42 (1.37-1.48) for males and 1.42 (1.34-1.50) for females. The elevated risk persisted when the study sample was limited to persons with unimpaired health
Conclusion: Both adolescents with severe and mild ADHD are at increased risk for obesity. Early preventive measures should be taken.