“Pesticides Tied to Childhood Cancers” said a headline in the Sept. 21, 2015, edition of The New York Times. It got people’s attention but may have triggered undue anxiety among some parents.

“This is a very complex subject and it’s dangerous to establish a cause-and-effect relationship in a newspaper headline,” said Dr. Michael McManus, a children’s cancer specialist at Marshfield Clinic. “There are many factors to consider why a child develops cancer, including environmental exposure, infections and genetic makeup.”

No increases here

McManus has seen no increase in childhood cancers, which he said are extremely rare. That means about 100 cases per million for children ages 2-4 and 14 cases per million for 16-year-olds.

This research combined data from 16 studies of children, 7,200 children diagnosed with cancer and 9,437 healthy children as controls. The studies compared children with and without cancer and learned who was exposed to indoor pesticides like roach and ant sprays, indoor flea foggers and even flea and tick pet collars.

A different perspective

Providing a different perspective from McManus is Dr. Matthew Keifer, former senior research scientist and director of the National Farm Medicine Center, a program of Marshfield Clinic Research Foundation. Keifer has worked on pesticide applicator monitoring programs in the United States and other nations.

“What the study authors are saying is probably true but the increase they observed was not huge,” Keifer said. “People should be aware of this but need not be alarmed because we are not talking about an outbreak.”

The study ultimately found the risk of childhood leukemia and lymphomas increased by 47 percent and the risk of childhood lymphomas increased by 43 percent among children exposed to pesticides. That increased risk may seem large but in fact is minimal when you consider that these diseases occur as rarely as 14 cases per million.

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Keep dangerous materials away from kids

In general, all adults should be alert to exposing children to pesticides and other chemicals inside or outside the house, McManus said.

“These chemicals are powerful tools; they’re toxic,” Keifer said. “They need to be respected and used exactly the way the label states and with care because they are poisonous.