August 25, 2010
Pesticide Exposure In Pregnant Women Linked To ADHD
Children whose mothers were exposed to certain types of pesticides while pregnant are more likely to suffer attention problems as they grow up, according to a new study by researchers at the University of California, Berkeley.
The study supports previous research showing that organophosphate pesticides can affect the human brain.
The researchers tested pregnant women to determine if their bodies had absorbed organophosphate pesticides, and then followed their children for several years as they grew.
The children of women with higher chemical traces of pesticides in their urine while pregnant were more likely to have symptoms of attention deficit hyperactivity disorder (ADHD) at 5 years of age, the researchers found.
"While results of this study are not conclusive, our findings suggest that prenatal exposure to organophosphate pesticides may affect young children's attention," wrote researcher Amy Marks and colleagues in a report about the study.
The researchers surveyed the mothers and administered standardized tests to the children to test for ADHD.
Organophosphates are designed to attack the nervous systems of insects by altering message-carrying chemicals known as neurotransmitters, including acetylcholine, which are vital to human brain development.
The researchers also conducted tests with Mexican-American women residing in the Salinas Valley of California, a region of extensive agriculture.
They tested urine samples from the expectant mothers for metabolites from pesticides, and then tested the children as they grew.
The results showed that while few symptoms were apparent at age 3, by age 5 the effects were considerable.
Indeed, the research revealed that a tenfold increase in pesticide metabolites in the mother's urine was linked to a 500 percent increase in the chances of ADHD symptoms in the child by age 5.
This trend was stronger among boys than in girls, the researchers found.
A smaller increase in risk of ADHD was seen among children with pesticide metabolites in their urine.
A separate study conducted in May of this year found that children with high levels of organophosphate traces in their urine were about twice as likely to develop ADHD as those with undetectable levels.
The United States has roughly 40 registered organophosphate pesticides.
On the Net:
- University of California, Berkeley
- The current study was published Thursday in Environmental Health Perspectives, and can be viewed at http://ehp03.niehs.nih.gov/article/info:doi/10.1289/ehp.1002056.