New Study Finds Pesticides Double Risk of ADHD in Our Children

In a new study just published in Pediatrics, researchers from the University of Montreal and Harvard University found evidence strongly indicating that pesticides could be a major cause of the alarming rise in ADHD in our children. Children who had higher than average biomarkers for organophosphate pesticides were nearly twice as likely to be diagnosed with ADHD. Previous studies found that pesticides may contribute to hyperactivity and cognitive problems in animals, but the new study is among the first to determine that it affects humans, too.

Among the study's findings:

* Children who have high levels of pesticide residues are 93% more likely to have ADHD.
and
* For every 55% increase in residue in urine, there is a 10% greater risk of ADHD.

"I think it's fairly significant. A doubling is a strong effect," said Maryse F. Bouchard, a researcher at the University of Montreal in Quebec and lead author of the study.

The study is the largest thus far to examine the effect of pesticides on child development and behavior, including ADHD. ADHD affects an estimated 4.5 million U.S. children. According to the Centers for Disease Control and Prevention, about 2.5 million kids take medication for the condition.

In the study, Bouchard and her colleagues measured levels of six pesticide metabolites in the urine of 1,139 children ages 8 to 15. The children were selected from the National Health and Nutrition Examination Survey between 2000 and 2004 and included 119 children who were diagnosed with ADHD.

Unlike other studies on the impact of pesticides, the new study provided a look into average insecticide exposure in the general child population instead of a specialized group (such as the children of farm workers). Organophosphates are commonly used on some of the crops children consume the most, such as frozen blueberries, fresh strawberries and celery. However, since some of the children who participated in the study were from urban areas, the results suggest that pesticide exposure comes from the air we breathe, as well as on the foods we eat. Bouchard said that because many pesticides leave the body after three to six days, the presence of residue shows that exposure is likely constant.

Cheminova, the Danish firm that is the world's largest manufacturer of malathion, declined to comment on the conclusions of the new study. Diane Allemang, vice president for global regulatory affairs, reported that she had not yet seen the study.

Bouchard's advice for parents: "I would say buy organic as much as possible. I would also recommend washing fruits and vegetables as much as possible."

The consumer advocacy organization Environmental Working Group echoes Bouchard's advice, advising shoppers to buy organic versions of a dozen fruits and vegetables that grow in the ground or are commonly eaten with the skin, because they're most likely to be contaminated.

When washing fruits and vegetables, be sure to wash and rinse them in cold tap water and scrub firm-skinned produce with a brush. Some people opt for the addition of hydrogen peroxide to their fruit and vegetable rinses for maximum removal of pesticides. Frozen fruits and vegetables should also be washed.

Don't wash produce with soap, though. Soap can leave behind detergent residues and more chemicals that everyone would do best to avoid.