Prenatal exposure to tobacco smoke and childhood exposure to lead are linked to an increased risk of developing attention deficit hyperactivity disorder (ADHD) in children.

According to a study published in Pediatrics, kids born to expectant moms who smoked are 2.4 times more likely to have ADHD.

Children with blood lead levels in the top third of the population, regardless of being less than the safe levels (10 micrograms per deciliter) prescribed by the Centers for Disease Control, had a 2.3-fold increased risk of developing the condition.

The risk of the condition was enhanced by over eight times in children exposed to both tobacco and lead, the study found.

"Our findings suggest that reduction of toxicant exposures may be an important avenue for ADHD prevention and they underscore the enormous burden that may be associated with continued exposure to tobacco and lead,” scientists concluded.

They estimated that eliminating exposure to these environmental toxicants can lower the risk of ADHD in children between the ages of 8 and 15 by 35 percent.

PKH/HGH