A new study suggests a potential link between allergy, asthma and attention-deficit hyperactivity disorder in children.
Experts say the number of children presenting with the three conditions is on the upswing in the United States.
As published in the journal Annals of Allergy, Asthma & Immunology, researchers found an increased risk of ADHD in boys who have a history of allergy or asthma. ADHD is most commonly found in males, while asthma is also more common in young boys than girls.
“We found there is an increased risk of ADHD in boys with a history of asthma and an even stronger risk associated with milk intolerance,” said Eelko Hak, lead study author.
For the study, researchers in the Netherlands and Boston studied 884 boys with ADHD and 3,536 boys without the disorder.
Of the children with ADHD, 34 percent had asthma and 35 percent had an allergic disorder.
The study suggests medications used to treat these conditions may be associated with an increased ADHD risk.
“Further research is needed to understand why there appears to be an increased risk of developing ADHD in children with allergy and asthma,” said Gailen Marshall, M.D., editor-in-chief of Annals of Allergy, Asthma & Immunology.
“Medications for these conditions far outweigh the risks, and can be life-saving in some conditions. Treatment should not be stopped, unless advised by a board-certified allergist.”
According to experts, allergy and asthma often run in families. If both parents have an allergy a child has a 75 percent chance of being allergic. If neither parent has allergy, the chance of a child developing an allergy is only 10 to 15 percent.
Allergists also know allergies and asthma are linked. An estimated 60 to 80 percent of children with asthma also have an allergy.
Although the cause of ADHD is unknown, this disorder is also thought to run in families.