Exposure to tobacco smoke and lead while pregnant leads to ADHD in children

November 23, 2009 by Shawn Douglas
Filed under: News, Pregnancy

Children exposed to tobacco smoke and lead while in the womb have higher risks of ADHD according to new research.

Researchers out of the Cincinnati Children’s Hospital Medical Center have found that when combined, tobacco smoke and lead, ingested while pregnant, create a significant risk of symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in children later in life.

The study, published today in the journal Pediatrics, focused on data collected from 2001 to 2004 on 3,907 children aged 8 to 15 in the United States. The researchers also polled mothers on their cigarette use during pregnancy.

Researchers found that when exposed to tobacco smoke prenatally, children were 2.4 times more likely to exhibit ADHD symptoms, and those exposed to lead were 2.3 times likely to have the symptoms. Researchers also pointed out that when looking at lead exposure in the blood, levels were found to be well below the Centers for Disease Control action level, suggesting that even small doses of the metal may have an effect on behavior.

When the two substances were combined in vitro, the team found an eight times higher risk of ADHD when compared to children not exposed to the two substances.

Dr. Tanya Froehlich, head author and physician in the Division of Developmental and Behavioral Pediatrics at Cincinnati Children’s said: “Tobacco and lead exposure each have their own important adverse effect. But if children are exposed to both lead and prenatal tobacco, the combined effect is synergistic.”

“We know from experimental research that exposure to tobacco smoke before birth interferes with chemical messengers in the brain, the dopamine system, linked to motivation and attention. These alterations are long-lasting.”

“It’s an important message to get out there because women need to know how important it is to stop smoking in pregnancy.”

“Also, we can reduce children’s lead exposure by helping them avoid old peeling paint, which contains lead, and getting them to wash their hands thoroughly after exposure to contaminated soil,” she added.

Dr. Robert Kahn, senior author and researcher at Cincinnati Children’s, agreed.

“Although we tend to focus on ADHD treatment rather than prevention, our study suggests that reducing exposures to environmental toxicants might be an important way to lower rates of ADHD,” he said.