Doctors at Cincinnati Children's Hospital examined data from a national health survey. Children whose mothers smoked during pregnancy and those with higher amounts of lead in their blood had more than double the risk for ADHD. But, when combined, the two toxins increased ADHD risk by 8 times.
Although the study was not designed to prove that smoke or lead actually cause the disorder, researchers say the take home message is clear. They want parents to rid their homes of lead and moms to stop smoking before becoming pregnant.