Attention-deficit/hyperactivity disorder can influence a child's weight in ways that will shape their long-term health, a new study says. The work is published in the Journal of the American Academy of Child & Adolescent Psychiatry . Kids with ADHD tend to have lower birth weight, which increases their risk of developmental delays and health problems , researchers in the U.

K. found. But these kids also are more likely to develop obesity after age 5, a weight swing that can place even more risk upon their health in adulthood, researchers said.

"Children with increased ADHD symptoms are typically lighter at birth than their peers but are later more likely to have obesity," researcher Claire Reed of the University of Southampton said in a news release. "Research into the 'when and why' regarding this turning point is scarce." For the study, researchers analyzed data on more than 7,900 children born between 2000 and 2002.

Of those kids, the team compared 442 with ADHD against nearly 5,400 without either an AHDH diagnosis or symptoms of the disorder. Kids in the ADHD group weighed less at birth on average compared with children without ADHD, researchers found. However, those differences in weight vanished quickly, and by nine months and at three years, the two groups weighed about the same.

Then, from age 5 onwards, the kids with ADHD were significantly more likely to have obesity, after excluding children taking stimulants for their condition, results show. The risk was most pron.