Exposure in the womb to tobacco and lead could be linked to attention deficit hyperactivity disorder in U.S. children, concludes a report by Environmental Health Perspectives, a peer-reviewed journal of the National Institute of Environmental Health Sciences.
The report studied 4,704 children ages 4 to 15, 4.2 percent of whom had ADHD. Based on their findings, the researchers estimate that prenatal tobacco exposure is associated with 270,000 cases of ADHD in U.S. children, while prenatal lead exposure could account for 290,000 cases.
However, the study found no connection between tobacco exposure after a child is born and ADHD. The study did not mention any connection between postnatal lead exposure and ADHD.