Childhood ADHD Linked to Obesity in Adults for First Time

Nancy A. Melville

May 20, 2013

Men who had attention-deficit/hyperactivity disorder (ADHD) as children show a significantly greater risk of being overweight or obese as adults, even if their ADHD has remitted in adulthood, according to a new 33-year follow-up study published online May 20 in Pediatrics.

Researchers led by Samuele Cortese, MD, PhD, from the Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience at Langone Medical Center, New York, evaluated 207 white men with childhood ADHD, referred at the average age of 8.3 years, who had follow-up interviews at the mean ages of 18, 25, and 41 years.

They found that, compared with a cohort of 178 boys without ADHD at age 18 and with 111 men without childhood ADHD at age 41, the men with ADHD in childhood had significantly higher body mass index (BMI) (30.1 vs 27.6; P = .001) and higher obesity rates (41.4% vs 21.6%; P =.001).

"Other studies have noted associations between ADHD and obesity, [but] our study was the first to do so in adults diagnosed as children," said one of the authors, F. Xavier Castellanos, MD, director of the Center for Neurodevelopmental Disorders at New York University's Child Study Center. "It is this convergence of results that enhances our confidence in the pattern of results."

The higher obesity and BMI rates remained in the childhood-ADHD group after adjustment for socioeconomic status and lifetime mental disorders.

"The long-term risk for obesity should be considered when managing children with ADHD," the authors state.

Risk Greatest in Those Who Recovered From ADHD

Contrary to the researchers' expectations, the increased risk of being obese or overweight was no lower among men who had remitted in adulthood, compared with those who had persistent ADHD.

In fact, those with persistent ADHD did not have significantly higher BMI or greater obesity rates compared with men who did not suffer from ADHD in childhood. "We were surprised that the men with persistent ADHD did not exhibit the greatest effects," Dr. Castellanos said. He pointed out, however, that this was the smallest subgroup (n = 24), "which made it most difficult to discern significant differences."

Men with remitted but not persistent ADHD, even after adjustment, had significantly higher BMI compared with those without childhood ADHD (P < .001) and were almost 3 times more likely to be obese (adjusted odds ratio, 2.99; P = .008).

Lifetime substance-use disorders also did not did not affect the relationship between childhood ADHD and obesity in adulthood.

The authors speculated that key signature psychological factors associated with ADHD could explain the increased risk for obesity.

"First, deficient inhibitory control and delay aversion, expressions of the impulsivity intrinsic to ADHD, may foster poor planning and difficulty in monitoring eating behaviors, leading to abnormal eating patterns and consequent obesity," they write.

"In addition, ADHD-related inattention and deficits in executive functions may produce difficulties in adherence to regular eating patterns, leading to abnormal eating behaviors."

The authors add that ADHD and obesity share the neurobiological features of dysfunction of frontostriatal dopaminergic pathways, which are related to impulse control, executive functions, and reward sensitivity.

"We think that the accumulated evidence, to which we have contributed, establishes that obesity in adulthood is a long-term risk of ADHD," Dr. Castellanos said.

"Obviously, obesity has become a risk for many, but it is an even greater risk for those with ADHD," he added. "Reversing obesity is extremely difficult, thus inculcating healthy eating habits and increasing physical activity need to become even higher priorities."

The authors have reported no relevant financial relationships.

Pediatrics. 2013. Published online May 20, 2013. Abstract


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