Researchers at Cincinnati Children's Hospital Medical Center examined data from the federal National Health and Nutrition Examination Survey on nearly 5,000 children ages 4 to 15, conducted from 1999 to 2002. The researchers found that children with blood lead concentrations of 2 micrograms or greater ran four times the risk of ADHD, compared to children with the lowest lead levels.
The researchers also found that their study confirmed previous research that linked prenatal exposure to cigarette smoke with ADHD. The Cincinnati researchers' study found that the risk of ADHD was 2.5 times higher in children exposed to tobacco smoke in the womb, compared to children who had not been exposed.
According to federal statistics, roughly 2 million U.S. children are being treated for ADHD -- characterized by impulsiveness, hyperactivity and lack of concentration -- which often make concentration in school difficult.
Critics of treating ADHD with amphetamine drugs -- which have been linked to increased risk of suicide and violent behavior, as well as heart failure -- say children need proper nutrition, not mind-altering drugs. Natural health advocates say hyperactive behavior can often be calmed with fish oil supplements and natural pine bark (pycnogenol) extract, in addition to healthy diets low in sugar and refined carbohydrates.