June 23, 2014

expert reaction to autism and pesticides

A study in Environmental Health Perspectives reported pregnant women living near farms that apply pesticides had an increased risk of having a child with autism spectrum disorder.

Dr Geoff Bird, Senior Lecturer at the MRC Social, Genetic, and Developmental Psychiatry Centre, King’s College London’s Institute of Psychiatry, said:

“These results will obviously provoke debate but we should remember that they do not show that pesticides cause autism. The data are based on a statistical relationship, a correlation. We know that parents of children with autism are more likely to show autistic-like traits than parents of typical children – it may be that parents of autistic children prefer to live in less densely-populated places like rural communities which just happen to be closer to farms which just happen to use pesticides.”

Prof David Coggon, Professor of Occupational and Environmental Medicine at the University of Southampton, said:

“This study is predicated on the assumption that application of a pesticide within 1.5 Km of a woman’s home will be an important determinant of her exposure to the chemical.  No evidence is presented to support the contention which, based on other research, seems unlikely to be true.

“Studies have suggested that there is greater exposure from other sources, such as use of pesticides within the home and low levels of pesticide residues in food. If it is true that most exposure is from other sources, then the reported correlation between agricultural pesticide use and developmental disorders is likely to be spurious.”

Prof Dorothy Bishop, Professor of Developmental Neuropsychology, University of Oxford, said:

“The authors conclude that exposure to pesticides during pregnancy is associated with neurodevelopmental disorders – autism or developmental delay – in the child. However, their main result shows closely similar rates of pesticide exposure for those with neurodevelopmental disorders and typically-developing children. Evidence for a link only came from more detailed analysis on a subset of the sample at specific stages of pregnancy, and this is hard to evaluate, because the numbers of children in this analysis are not given.”

‘Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study’ by Shelton et al. published in Environmental Health Perspectives on Monday 23^rd June.

Declared interests

None declared