Is childhood cancer linked to pesticide exposure?

February 15, 2010

The study
Between January 2005 and January 2008, Offie Soldin, PhD, studied the association between common household pesticides and acute lympho-blastic leukemia (ALL), a childhood cancer that typically develops between ages three and seven. Compared to child-mother pairs without cancer, the urine of children with ALL and their mothers contained elevated levels of pesticides.

“Participation was beyond belief,” said Soldin. The 41 pairs of children with ALL and their mothers plus 41 control pairs were all volunteer participants from the Washington metropolitan area.

Right away, Soldin cautions on the weakness of the study, “I focused on children that already had the cancer. They could have had it at any time so we are unable to show causality.” Assuming some children are born with ALL, Soldin asks, “How long was it incubating there? I don’t know.” Furthermore, she says, data on the mothers’ pesticide exposure came from a questionnaire filled out by memory. Since pesticides are often
used in public places and on food without warning, people may not even be aware of what they are being exposed to.

Although it might be impossible to determine the definitive cause for developing ALL, Soldin says, “I think maternal exposure during pregnancy is extremely serious.  Timing and dosage are critical.”

The dilemma about causality, as Soldin describes it, is that the only way to really show whether pesticides cause cancer would be to conduct randomized controlled trials, which are ethically out of the question.

Despite this, the study is generating a lot of public interest. As Soldin says, “A few good things that have come out of this are that people really want to listen and they want to hear this— it’s opened doors.”

A personal connection
Soldin had the rare opportunity of participating in her own study, as a control
subject. “I had a daughter that matched the criteria. It was a way to involve her in research and it was a learning experience for her.” The Centers for Disease Control, which conducted testing for the study pro-bono, coded test subjects, which made Soldin blind to the data and validated the
results.

Besides collecting urine samples, Soldin also took hair and wipes from the participants’ homes to test for pesticides, but the hair and the wipes ended up being too expensive to include in the study. LM

Meet Offie Soldin
Title: Associate Professor of Oncology and Medicine, Georgetown University.

Education :
• MS, Pathology (University of Tel-Aviv)
• PhD, Molecular Virology & Reproductive Immunology (McMaster University)
• MBA, Management of Science and Technology/International Health
(George Washington University)

Research Focus:
Childhood cancer and the environment; effects of tobacco smoke on hormones; hormone changes in pregnancy

Limiting Pesticide Exposure In Your Home
“You always have to wash your hands,” says Soldin. She also recommends carefully washing vegetables before eating them—especially for pregnant women—and reducing pesticide use in the home. “I used to use pesticides in the house every year,” she says, “I don’t do that anymore.”

Because exposure comes from many sources, “not just from the home”, it can be tricky to protect yourself. Soldin cites pets, lawns and vegetable diets among the various factors leading to pesticide exposure. The best we can really do, she says, is to make informed decisions.

Author: Amy Dusto and Allison T. Whitney
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