Children who were exposed early in life to a widely used class of pesticides may have less lung capacity, research suggests.
A new study links the levels of organophosphate pesticide metabolites in the urine of 279 children living in California’s Salinas Valley with decreased lung function. Each tenfold increase in concentrations was associated with a 159-milliliter decrease in lung function, or about 8 percent less air, on average, when blowing out a candle.
The magnitude of this decrease is comparable to a child’s secondhand smoke exposure from his or her mother.
The findings are the first to link chronic, low-level exposures to organophosphate pesticides—chemicals that target the nervous system—to lung health for children.
“Researchers have described breathing problems in agricultural workers who are exposed to these pesticides, but these new findings are about children who live in an agricultural area where the organophosphates are being used, says study senior author Brenda Eskenazi, professor of epidemiology and of maternal and child health at the University of California, Berkeley. “This is the first evidence suggesting that children exposed to organophosphates have poorer lung function.”
The children were part of the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal study that follows children from the time they are in the womb up to adolescence.
Researchers collected urine samples five times throughout the children’s lives, from age 6 months to 5 years, and measured the levels of organophosphate pesticide metabolites each time. When the children were 7 years old, they were given a spirometry test to measure the amount of air they could exhale.
The study, published in the journal Thorax, accounted for other factors that could affect the results, such as whether the mothers smoked, air pollution, presence of mold or pets in the home, and proximity to highways.
Greater risk of COPD
“The kids in our study with higher pesticide exposure had lower breathing capacity,” says study lead author Rachel Raanan, who conducted the research while she was a postdoctoral scholar in Eskenazi’s lab. “If the reduced lung function persists into adulthood, it could leave our participants at greater risk of developing respiratory problems like COPD (chronic obstructive pulmonary disease).”
The study did not examine the pathways for the children’s exposure to pesticides, but the researchers did recommend that farmworkers remove their work clothes and shoes before entering their homes. They also suggested that when nearby fields are being sprayed with pesticides, children be kept away and, if indoors, windows should be closed. Pesticide exposure can also be reduced by washing fruits and vegetables thoroughly before eating.
“This 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 could be harmful to the developing lungs of children,” Raanan says.
“Given they are still used worldwide, we believe our findings deserve further attention.”
The researchers note that although organophosphate pesticides are still widely used, most residential uses of organophosphate pesticides in the United States were phased out in the mid-2000s.
In California, use of organophosphates in agriculture has also declined significantly from 6.4 million pounds in 2000, when the study began, to 3.5 million pounds in 2013, the year with the most recent pesticide use data. Just last month, the S. Environmental Protection Agency proposed eliminating all agricultural uses of chlorpyrifos, one of the most heavily used organophosphates, and others are also under evaluation, steps that will continue the trend of declining use.
“Chronic obstructive pulmonary disease is an increasing cause of death around the world,” says study coauthor and pulmonary specialist John Balmes, professor of environmental health sciences with a joint appointment at the UC San Francisco School of Medicine.
“Since we know that reduced lung function increases the risk for COPD, it is important to identify and reduce environmental exposures during childhood that impair breathing capacity.”
The National Institute of Environmental Health Sciences and the EPA supported the work. Raanan’s fellowship was supported by the Environment and Health Fund in Israel.
Source: UC Berkeley