News article

Childhood ADHD linked to obesity in teens

Posted:  Monday, March 10, 2014

Having attention-deficit/hyperactivity disorder (ADHD) may put children at higher risk of becoming obese in adolescence, a new study suggests. Obesity is a common, serious, and costly problem in America today. The CDC reports that 36% of adults and 17% of children in the U.S. are obese. Among Hispanic and Black youth, obesity rates are even higher when compared to Whites. The medical costs alone for people who are obese are close to $150 billion annually.

ADHD is a mental disorder characterized by hyperactivity, impulsivity, inattention and inability to focus. It affects approximately 6.8 percent of U.S. children ages three to 17 in any given year, according to a recent report by the U.S. Centers for Disease Control.

"In general, people think of children with hyperactivity as moving around a lot and therefore should be slim," so this connection seems counterintuitive, senior author Alina Rodriguez said. She worked on the study at Imperial College London in the UK. But kids who have ADHD tend to be overactive in a fidgety way, Rodriguez said.

"Children with ADHD are not more likely to participate in physical activity, as we show in our report," she told Reuters Health in an email. Rather, her team's results suggest kids with behavioural difficulties are actually less likely to be active as they get older.

According to the American Psychiatric Association, about five percent of U.S. kids have ADHD, which usually involves having trouble paying attention and poor impulse control.

The new study included almost 7,000 Finnish children born in 1986. When the kids were seven or eight years old, teachers told the researchers about their symptoms of ADHD or conduct disorder, a psychological disorder involving antisocial behaviour. Parents reported their children's weight and height and how much time they spent actively playing.

When the kids were 16, the researchers asked their parents about their ADHD symptoms and the teens themselves about their physical activity and how often they engaged in “binge eating." The researchers also got information on young people's height, weight and waist size from doctors' examinations.

Kids who had symptoms of ADHD at a young age were almost twice as likely to be obese as teens, according to results published in the Journal of the American Academy of Child and Adolescent Psychiatry. That was true even after the researchers took their childhood weight into account.

Childhood ADHD or conduct disorder symptoms were linked with too little physical activity in adolescence, but not with binge eating.

Kids who were less active in childhood were also more likely to have trouble paying attention as teens. That means the relationship between ADHD and lack of physical activity probably goes in both directions, the authors write.

Researchers have known about the link between ADHD and later obesity for perhaps a decade, according to Dr. L. Eugene Arnold, a child psychiatrist and professor at The Ohio State University in Columbus.

Parents of kids with ADHD should encourage active pursuits and join the kids in being active if necessary, limit screen time and keep healthy snacks on hand to help prevent teenage weight problems, Arnold said.