A federal ban on two insecticides is benefiting newborn babies, according to a just-released study by the Columbia Center for Children's Environmental Health, part of the Mailman School of Public Health at Columbia University . The results of the study -- the first to demonstrate the benefits of the ban during pregnancy in human subjects -- will be published in Environmental Health Perspectives, a peer-reviewed scientific journal.
The study looked at the impact on fetal growth of chlorpyrifos and diazinon -- two insecticides whose use in households was banned by the federal government starting in 2000. The two insecticides had been among the most commonly used for residential pest control (available in numerous household sprays). Chlorpyrifos, for instance, was the most frequently used residential insecticide in New York City prior to the ban. Both are still widely used in agriculture and continue to be found in the food supply.
The research involved a sample of 314 infants of African-American and Dominican women in Washington Heights, Central Harlem and the South Bronx . The researchers measured the levels of the two insecticides in blood drawn from the umbilical cords at birth, both before and after the ban, and correlated those levels with the babies' birth weight and length.
Prior to January 1, 2001, newborns with combined insecticide exposures in the highest 26 percentile had birth weights averaging almost 200 grams (almost half a pound) less than infants with no detectable levels. There was also a highly significant inverse association between the sum of the two insecticides and birth length.
After January 1, 2001, the combined insecticide exposure levels had been reduced substantially, and impact on fetal growth was no longer apparent.
"This human study confirms the developmental impact, shown previously in animal studies, of these insecticides," said Robin M. Whyatt, an assistant professor at the Mailman School and principal author of the study. "It also demonstrates the positive effect of the federal ban, which has substantially reduced exposures and benefited human health. The differences in fetal growth seen here are comparable to the differences between babies whose mothers smoke during pregnancy and babies whose mothers don't. The fact that the ban was associated with such an immediate change in birth weight and length provides considerable evidence of cause and effect."
"This study is good news for our nation's children," said Frederica P. Perera, director of the Center and the study team leader. "The evidence that birth weight increased following the Environmental Protection Agency's regulatory action implies important benefits for the children's future health and development. At the same time, the results highlight the need to address continuing prenatal exposures to these and other toxic pesticides."
The research is part of a broader, multi-year research project, "The Mothers & Children Study In New York City," started in 1998, which examines the health effects of exposure of pregnant women and babies to air pollutants from vehicle exhaust, the commercial burning of fuels, and tobacco smoking, as well as from residential use of pesticides and allergens.
This study was made possible by research grants from the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, as well as a number of generous private foundations. Other co-authors of this study include Virginia Rauh from the center, Dana Barr from the Centers for Disease Control and Prevention and David Camann from Southwest Research Institute.