Written by Chrystal Moulton, Staff Writer. Research shows that children with autism spectrum disorder were 60% more likely to have been exposed to organophosphate based pesticides.
Pesticides are compounds commonly used to protect agriculture from parasites and insects that damage crops. However, many studies have found links between the use of pesticides and the risk of developmental disorders in infants and children. (1-3) The EPA has conducted research highlighting the effects of certain pesticides on the growth and the development of children. (4)
In a recent study (5), researchers wanted to find the relationship between agricultural pesticides and brain development in children whose mothers’ lived close to agricultural areas. Information taken from an ongoing study formally known as the CHARGE study was used to determine a link between autism spectrum disorder, delayed development, and certain classes of pesticides.
The study was a population based case control study which included 970 women who lived within 1.25km, 1.5km, and 1.75km of pesticide application near their homes during pregnancy between 1997 and 2008. Pesticide application between the years 1997-2008 was reported in the California Pesticide Use Report. During that time, there were 486 confirmed cases of autism spectrum disorder and 168 cases of developmental delay. Using odds ratio to calculate risk, researchers compared the occurrence of autism spectrum and developmental delay with children who had normal development living within the same vicinity.
Researchers found that children with autism spectrum disorder were 60% more likely to have been exposed to organophosphate based pesticides under a mile from their homes (1.25km; aOR=1.60, p<0.05). Children with developmental delay were about 150% more likely to have been exposed to carbamate pesticides (1.25km; aOR=2.48, p<0.05). Evaluation of chlorpyrifos pesticide exposure showed that every 100 pound increase in chlorpyrifos application was associated with a 14% increase in the prevalence of autism spectrum disorder (aOR=1.14, p<0.05). Furthermore, researchers found that exposure to organophophates in the 2nd and 3rd trimester was significantly associated with autism spectrum (1.5km; 2nd trimester aOR=1.85, 3rd trimester aOR=2.07, p<0.05). Also, exposure to pyrethroid insecticide before conception or during the 3rd trimester significantly increased the risk of child born with autism spectrum (1.5km; pre-conception aOR=1.82, 3rd trimester aOR=1.87, p<0.05) and developmental delay (1.5km: pre-conception aOR=1.44, 3rd trimester aOR=1.75, p<0.05). Risk of developmental delay was also significantly increased when exposed to carbamates during pregnancy (p<0.05).
Overall, researchers found that exposure to organophosphates and chlorpyrifos are significantly associated with the risk of autism spectrum disorder, while pyrethroids and carbamates were significantly associated with the risk of developmental delay. Researchers stated that the evidence strengthens general concern about the neurotoxic effects of pesticides on fetal development.
Source: Shelton JF, Geraghty EM, Tancredi DJ, Delwiche LD, Schmidt RJ, Ritz B, Hansen RL, Hertz-Picciotto I. 2014. Neurodevelopmental disorders and prenatal residential proximity to agricultural pesticides: the CHARGE study. Environ Health Perspect 122:1103–1109; http://dx.doi.org/10.1289/ehp.1307044
Click here to read the full text study.
Posted August 4, 2014.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Lee PC, et al. Functional paraoxonase 1 variants modify the risk of Parkinson’s disease due to organophosphate exposure. Environ Int. 2013 Jun;56:42-7. doi: 10.1016/j.envint.2013.03.004.
- Rauh VA, et al. Impact of prenatal chlorpyrifos exposure on neurodevelopment in the first 3 years of life among inner-city children. Pediatrics. 2006 Dec;118(6):e1845-59.
- Roberts EM, et al. Maternal residence near agricultural pesticide applications and autism spectrum disorders among children in the California Central Valley. Environ Health Perspect. 2007 Oct;115(10):1482-9.
- EPA/NIEHS Children’s Environmental Health and Disease Prevention Research Centers (CEHCs). Accessed July 28, 2014.
- Shelton JF, et al. Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study. Environ Health Perspect. 2014 Jun 23.
