ADHD and Obesity Risk Are Associated in Children Over Time

Higher attention-deficit/hyperactivity disorder (ADHD) symptoms are associated with increased body mass index (BMI) in children and adolescents aged 7, 11, and 14 years, with the relationship being more pronounced in girls, according to study results published in the Journal of the American Academy of Child & Adolescent Psychiatry.

Researchers used data from the Millenium Cohort Study (MCS) to investigate the longitudinal relationship between ADHD symptoms and body weight from birth to late adolescence, exploring gender differences and the age at which individuals with ADHD shift from being underweight towards overweight. The population involved over 19,000 families with children born between 2000 and 2002. Data were collected at seven time points from 9 months to 17 years of age.

ADHD diagnoses, and the subsequent ADHD and control participants, were identified using scores on the Strength and Difficulties Questionnaire (SDQ). The researchers then conducted a longitudinal analysis using random intercept cross-lagged panel models (RI-CLPM) to examine the relationship between SDQ square and BMI z-score. Model fit was determined using comparative fit index (CFI) and root mean square error of approximation (RMSEA).

Participants taking ADHD medication were excluded from certain analyses, with 141 excluded from cross-sectional comparisons and 83 adjusted for in longitudinal analyses.

Children with ADHD, compared to those without, had a significantly lower mean birth weight (3.32 kg vs 3.39 kg, respectively), with a small effect size (Cohen d=0.13). By nine months, this difference was no longer significant. From age five onward, children with ADHD (excluding those on medication) were more likely to have obesity, with odds ratios between 1.57 and 2.46, indicating small to medium effect sizes.

In the RI-CLPM longitudinal analysis, autoregressive paths comparing SDQ scores and BMI z-scores were significant in both girls (N=4051) and boys (N=3857) separately (P<.001). Additionally, the researchers found good model fit for both genders (Girls: CFI=0.988, RMSEA=0.041; Boys: CFI=0.986, RMSEA=0.045).

In girls, SDQ scores at ages 7, 11, and 14 significantly predicted BMI z-scores at ages 11, 14, and 17, respectively. In boys, SDQ score at age 11 predicted BMI z-score at age 14. A sensitivity analysis with only diagnosed ADHD participants showed similar results, though results at age 17 were not statistically significant. Effect sizes were similar to those in the main analyses.

The study authors concluded, “Our results suggest there may be a sensitive time period between the ages of three and five years during which…higher ADHD symptoms become associated with obesity.”

Study limitations include that the sample may not represent population estimates, the SDQ score is not a diagnostic tool, and the lack of an analysis of the differential effects of each symptom dimension on obesity.

This article originally appeared on Psychiatry Advisor