High Lead and Mercury Exposure Linked to ADHD in Children

Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common neurobehavioral disorders haunting the young generation in the country.

ADHD children experience problems with attention, troubles in controlling impulsive behaviors or acting without thinking about the consequences and hyperactivity. According to federal records, one in 11 American children is affected with this disorder.

Efforts have been going on from a long time to find out the exact causes that lead to the occurrence as the disorder can have a negative impact on learning and academic development.

Bringing new hopes in preventing the occurrence, a new study says exposure to heavy metals like mercury and lead can make children at greater risk of developing the disorder, WebMD reported.

Mercury and lead are known to pose health risks to children. Lead poisoning can lead to a wide range of health problems in children and can affect the function of every system of the body. High levels of lead exposure can lead to coma, convulsions and even death and low levels of exposure can result in low intelligence levels.

The lead-based paint used until 1978, was banned later finding the risks. Citing the risks associated with high lead exposure in children, CDC lowered the lead levels from 10 micrograms per deciliter to five micrograms, recently.

Mercury is naturally present in the air. Industries play a major role in increasing its level in the environment. This mercury is later gathered in oceans and streams and transformed into methylmercury. Fish and shell fish that lives in the ocean and streams thus absorb this mercury. Eating these fish, with traces of mercury can be harmful to children and pregnant women.

For the study, the researchers looked at 300 Inuit children in Quebec, Canada.  The Inuit diet includes food with high levels of mercury like Beluga whale meat and lead- ducks and geese killed with shot pellets.

Umbilical cord blood of all the participants was tested at birth.  Later, when the participants reached between eight and 14 years, their teachers filled a questionnaire and shared details about the children's behavior.

Results showed nearly 14 percent of the children having symptoms of ADHD, either inattentive or hyperactive-impulsive.

Further investigation showed children having highest concentrations of mercury in cord blood suffering from the disorder more than others. Apart from that, children with even moderate level of lead were found four times higher risk of hyperactive problems compared to children with low levels.

Findings have been published in Environmental Health Perspectives.