A common type of pesticide could have damaging effects on the lungs of young children, a new study suggests — and that could lead to more serious health conditions down the road.
The research, published Thursday in the journal Thorax, finds that early exposure to organophosphates — a common class of pesticides — is associated with decreased lung function in children. While some past research has indicated such effects in adults, this study is the first to examine the association in children, said the paper’s lead author, Rachel Raanan. She conducted the research as a postdoctoral scholar in the lab of senior author Brenda Eskenazi at the University of California, Berkeley’s School of Public Health.
Organophosphate pesticides are used widely in agriculture throughout the world and in the United States, although their use has been restricted in certain ways in the U.S. — they’re generally no longer used in residential settings, for instance — in recent decades.
Acute exposure to organophosphates can be highly toxic — they have been known to cause headaches, vomiting and even seizures or coma. Scientists are still working to understand the effects of long-term, lower-level exposure. Some studies of adults have suggested that exposure is linked to respiratory problems — but Raanan notes that they generally relied on self-reported exposure to the pesticides and did not include biological tests for the presence of the chemicals in the body. But the new study does.
The researchers conducted a longitudinal study, meaning they studied the same group of children from birth onward — more than 200 in total, all residents of California’s Salinas Valley. Many of them lived in households with agricultural workers and were likely exposed to pesticides either on the clothing of their family members or simply by living and playing outside in close proximity to areas where the pesticides had been used.
At periodic intervals (ages 0.5, 1, 2, 3.5 and 5 years), the researchers tested the children’s urine for evidence of organophosphates. When the children reached age 7, the researchers tested them to see how healthy their lungs were. They did this using a type of test called spirometry, in which the children were asked to blow into a machine that measured how much air they were able to expel, and how quickly. The researchers were particularly interested in two metrics: how much air the children were able to expel in one second, and how much air they were able to expel in total.
They found that exposure to the pesticides was associated with poorer lung function: Children with higher concentrations of organophosphates in their urine were not able to expel as much air. This is worrying because it could be a predictor of certain lung diseases later in life, such as chronic obstructive pulmonary disease (which is one of the leading causes of death in the U.S.), said Raanan in an email to The Post.
The study “adds another bit of evidence that what we breathe in on a chronic day-in and day-out basis can affect our lungs in an adverse way,” said James Gauderman, a professor at the University of Southern California’s Keck School of Medicine, who was not involved with this paper. Some of Gauderman’s recent research has focused on the effects of exposure to other types of air pollutants, such as particulate matter or ozone.
As far as the physical ways that organophosphates, among other pollutants, cause damage to the lungs, Gauderman said “that’s a question that lot of us are struggling with, and I think nobody really knows exactly what’s happening.”
Organophosphates are known to inhibit the function of an enzyme called acetylcholinesterase, which is important for healthy nerve function in the body — that’s how it’s so effective as a pesticide — and this can lead to breathing difficulties, among other effects. Additionally, long-term exposure to irritants like pesticides could cause chronic inflammation in the lungs, which can lead to permanent damage over time, Gauderman said.
The study “adds exposure to [organophosphate] pesticides to the growing list of environmental exposures, including air pollution, indoor cook stove smoke and environmental tobacco smoke that may play a key role in the pathophysiology of chronic respiratory disease in children,” the authors write. Thus, the story highlights a need for investigation into the extent of organophosphate pesticide use, in California and elsewhere — as the authors note, these pesticides are still used widely throughout the world.
In the course of his research on air pollution, Gauderman said he and his colleagues found that “improvements in air quality that have occurred over the last couple decades in southern California have been linked back to very significant improvements in children’s health over the past 20 years.” So, he said, one could hope that reductions in pesticide use might carry the same benefit down the line.
“One could…suggest that these exposures that these kids are having in agricultural areas that are reducing those kinds of pesticide exposures, through whatever mechanisms, would likely carry downstream improvements in the next generation of kids that are breathing that air,” Gauderman said.