MONDAY, May 20 (HealthDay News) -- Boys who are diagnosed with attention deficit-hyperactivity disorder (ADHD) are twice as likely to become obese adults as those who didn't have the disorder when they were young, a new 30-year study shows.
Researchers found that men with childhood ADHD tended to have a higher body-mass index (BMI) and obesity, even if they no longer had symptoms of the disorder. Socioeconomics made no difference; well-off or poor, they tended toward obesity.
"The bottom line is, boys who were hyperactive when followed up for more than 30 years turn out to be more likely to be obese than comparable kids from their same communities," said study co-author Dr. Francisco Xavier Castellanos, a professor of child and adolescent psychiatry in the Child Study Center at NYU Langone Medical Center in New York City.
"That really seems to be reflective of their early hyperactivity. It doesn't matter what their current diagnosis is so much, so we think these are longstanding issues that likely arose in early adolescence," he added.
A lack of impulse control and poor planning skills, symptoms often associated with ADHD, could lead to poor eating habits and food choices as well as the tendency to overeat, the study authors speculated.
"It fits with other studies, and suggests that the inability to control one's impulses, the tendency to be relatively reward-driven, may represent a risk of obesity over time," Castellanos said.
The study, published online May 20 and in the June print issue of Pediatrics, tracked 111 men diagnosed with childhood hyperactivity, touching base with them at ages 18, 25 and 41. By adulthood, 41 percent had become obese, compared with a non-hyperactive control group that had a 22 percent obesity rate.
The results are somewhat confounding, Castellanos said.
"The pattern of results to a certain extent was counterintuitive," he said. "We thought we would get the strongest effect in those men who manifested ADHD as adults, and that wasn't the case. That suggests that it's not something that is very tightly related to the current diagnosis, but the tendency to have the diagnosis."
The findings run counter to an earlier study that showed that hyperactive adult men had a greater tendency for obesity than men who left childhood ADHD behind, said Dr. Craig Surman, scientific coordinator for the Adult ADHD Research Program at Massachusetts General Hospital in Boston.
"So, the simple story here would be we don't know, because you have to replicate studies to know," he said. "The question now becomes why the findings are different."
Future research also needs to consider whether women with childhood ADHD are as likely as men with childhood ADHD to become obese, and whether controlling hyperactivity through the use of medication can have an impact, Surman said.
ADHD is more common in boys than girls, with 12 percent of U.S. boys aged 3 to 17 receiving the diagnosis, according to the U.S. Centers for Disease Control and Prevention.
The link between ADHD and obesity has become a topic of great interest as elevated rates of obesity have been reported in children with the disorder, Surman said. Obesity can lead to heart disease and diabetes later in life.
"It's very important to understand the ways ADHD affects life and self-care," Surman said. "We've known for some time that it's not just people's desks and houses that are messy. For some people, it's a lack of ability to control how to care for themselves as well."
The U.S. National Institutes of Health has tips for healthy weight loss.