Pesticides
( IN PHOTO)A worker scatters pesticide at a rice field in Tangerang, August 27, 2014. Indonesia's powerful anti-graft agency will launch a probe into the nation's subsidised rice scheme unless major flaws are fixed, threatening moves to expand the role of the state food buying agency into other staples such as corn, beef and sugar. Picture taken August 27, 2014. REUTERS

A recent study carried out at the Cincinnati Children's Hospital Medical Center has found an association between a common pesticide, pyrethroid exposure and attention deficit hyperactivity disorder, or ADHD in children and young teens. The study authors in their findings published online in the journal Environmental Health have suggested that attributes of ADHD such as hyperactivity, impulsiveness and inattentiveness were found to be much stronger among boys than in girls who were exposed to this pesticides.

However, they were not able to establish the cause and relationship behind this association. Tanya Froehlich, MD, a developmental paediatrician at Cincinnati Children's and the study's corresponding author says, “Given the growing use of pyrethroid pesticides and the perception that they may represent a safe alternative, our findings may be of considerable public health importance."

In the year 2000-2001, the United States Environmental Protection Agency had banned two of the most commonly used organophosphate (organic compounds containing phosphorus) pesticides from residential use. This ban led to a significant rise in the use of pyrethroid pesticides for residential pest control and public health purposes as well as agriculture. The pesticide was considered to be a safe option since it was not as acutely toxic as the banned organophosphates.

The research study was carried out on nearly 700 children aged between 8 and 15 years old, who had taken part in the 2000-2001 National Health and Nutrition Examination Survey. Urine samples of these children were checked for the levels of 3-PBA, a chemical which acts as a biomarker of exposure to pyrethroids. The result of the analysis revealed that those boys who has detectable levels of 3-PBA in their urine were three times more likely to have ADHD than those with no detectable 3-PBA.

Moreover, there was a 50 percent increase in the chances of exhibiting symptoms such as hyperactivity and impulsivity in boys who showed 10-fold increase in 3-PBA levels in their urine. The researchers also reported that increased levels of 3-PBA were not associated with risk of ADHD or its symptoms among girls. Froehlich says in her conclusion that, “Our study assessed pyrethroid exposure using 3-PBA concentrations in a single urine sample. Given that pyrethroids are non-persistent and rapidly metabolized, measurements over time would provide a more accurate assessment of typical exposure and are recommended in future studies before we can say definitively whether our results have public health ramifications."

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