The link between attention-deficit/hyperactivity disorder and later obesity may exist for both children with ADHD treated or not treated with stimulants, according to a study published online in Pediatrics March 17.
A longitudinal analysis of electronic health records for 163,820 Pennsylvania children, aged 3-18 years and 91% of whom were white, revealed variations in body mass index (BMI) trajectories for children with untreated ADHD, with ADHD and taking stimulant medications, and without ADHD, reported Dr. Brian Schwartz of the Johns Hopkins Bloomberg School of Public Health, Baltimore, and his colleagues. Among the children, 8.4% were diagnosed with ADHD, 6.8% had been prescribed stimulants, and 9.5% had either an ADHD diagnosis or a stimulant prescription (Pediatrics 2014 [doi:10.1542/peds.2013-3427]).
Dr. Schwartz’s team analyzed modeled untransformed BMI values instead of BMI z scores because the former "yields estimates that are more interpretable, precise, and sensitive to factors that alter change," they wrote. The researchers identified a curvilinear average trajectory of BMI increasing with age, with girls having higher BMIs than boys at all ages and black children diverging by age 5 and continuing to widen with age.
Compared with children who neither had ADHD nor were taking stimulants, children with ADHD who were not taking stimulants showed more rapid BMI growth after age 10 years. Children prescribed stimulants but lacking an ADHD diagnosis had a lower average BMI trajectory than did the controls (neither ADHD nor stimulant use).
Meanwhile, those with ADHD and taking stimulants had slower BMI growth in early childhood but later "rebounded," ending with BMIs in late adolescence that exceeded those of controls – especially if they started taking stimulants at a younger age and took them for longer. "The earlier stimulants were ordered, the earlier and stronger that BMI growth ‘rebounded’ and eventually exceeded values in controls," the researchers wrote.
The findings suggest that stimulant use, rather than ADHD itself, is most strongly associated with growth trajectories in childhood, early BMI rebound, and later obesity," Dr. Schwartz’s team wrote. The researchers discussed possible ways that stimulants might affect usual growth patterns and noted that "behavioral therapy, specifically parent training, can be effective for ADHD management and has no known BMI rebound effect."
The study was funded by the National Institutes of Health. No disclosures were reported.