(PhysOrg.com) -- The symptoms of attention-deficit/hyperactivity disorder present in childhood are associated with an increased risk of being obese as an adult, and the greater the symptoms, the greater the risk, according to a study by Duke University Medical Center researchers.
"This is the first study to take this concept out of the clinic and into the population and show that it's not just the diagnosis of ADHD that matters; it's the symptoms," said Scott Kollins, PhD, director of the Duke ADHD Program and co-author of the study.
The population study examined symptoms of inattention, hyperactivity and impulsivity along with body mass index, waist circumference, and blood pressure among 15,197 adolescents from the National Longitudinal Study of Adolescent Health. The adolescents were followed from 1995 through 2009.
The results, published online in the International Journal of Obesity, show that having three or more of any of the symptoms studied significantly increased the odds of being obese.
"It's a dose effect," explained Bernard Fuemmeler, PhD, MPH, lead author of the study and director of the Pediatric Psychology & Family Health Promotion Lab in the Department of Community and Family Medicine at Duke. "We showed that as the number of symptoms increase, the prevalence of obesity also increases."
Among children with only hyperactive or impulsive symptoms, the odds of being obese increased to 63 percent and hyperactive or impulsive symptoms led to greater weight gain in the transition from adolescence to adulthood, making these ADHD symptoms the most significant risk factor studied.
The broader implication, according to Fuemmeler, is that research like this may offer clues to what's driving the obesity epidemic.
"The findings support the idea that certain self-regulation capacities, like the ability to regulate one's impulses, could be a relevant trait to understanding why some people may be more vulnerable to obesity," he explained.
The researchers also studied the association between ADHD symptoms and high blood pressure, but concluded that while there was a link it was related more to the adolescents' weight than their ADHD symptoms.
"The most exciting thing about this research is it gives us a thread to follow in determining why kids with ADHD symptoms might be at risk for developing obesity," Kollins said. "It establishes the path for identifying these kids earlier and focusing on intervention methods."