Kasvinsuojeluaineet aiheuttavat ADHD:ta

ADHD in kids tied to organophosphate pesticides

18.05.2010 - Epidemiology

By Frederik Joelving

NEW YORK (Reuters Health) - Children exposed to organophosphates could have a higher risk of attention-deficit/hyperactivity disorder (ADHD), according to a new study.

Researchers tracked the pesticides' breakdown products in urine and found that children with high levels were almost twice as likely to develop ADHD as those with undetectable levels.

The findings are based on data from the general US population.

"There is growing concern that these pesticides may be related to ADHD," said Marc Weisskopf of the Harvard School of Public Health, who worked on the study. "What this paper specifically highlights is that this may be true even at low concentrations."

Organophosphates were originally developed for chemical warfare, and they are known to be toxic to the nervous system. There are about 40 organophosphate pesticides such as malathion registered in the US, the researchers wrote in the article, which was published online May 17th in Pediatrics.

Weisskopf said the compounds have been linked to behavioral symptoms common to ADHD -- for instance, impulsivity and attention problems -- but exactly how is not fully understood.

Although the researchers had no way to determine the source of the breakdown products they found, Weisskopf said the most likely culprits were pesticides and insecticides used on produce and indoors.

The researchers' sample included 1,139 children between 8 and 15 years. They interviewed the children's mothers, or another caretaker, and found that about one in ten met the criteria for ADHD, which concurs with estimates for the general population.

After accounting for factors such as gender, age and race, they found the odds of having ADHD rose with the level of pesticide breakdown products.

For a 10-fold increase in one class of those compounds, the odds of ADHD increased by more than half. And for the most common breakdown product, called dimethyl triophosphate, the odds of ADHD almost doubled in kids with above-average levels compared to those without detectable levels.

"That's a very strong association that, if true, is of very serious concern," said Weisskopf. "These are widely used pesticides."

Source: www.pediatrics.org/cgi/doi/10.1542/peds.2009-3058