Children, Cancer, and the Environment
Do pesticides cause cancer in children?
There are a variety of reasons to believe that childhood cancer may be linked to pesticides. The forms of childhood cancer linked to exposure to pesticides by the child, or the parent, or both include leukemia, non-Hodgkin’s lymphoma, Wilms tumor, Ewing’s sarcoma, and soft tissue sarcoma.
Many pesticides that have been found to cause cancer are still in use. For example, a 1990 review reported that 24 of the 51 pesticides found by the National Toxicology Program to be carcinogenic in laboratory animals were still in use (1). By 1997, 8 of 26 pesticides classified by the International Agency for Research on Cancer to have "sufficient" evidence to be considered carcinogenic were still registered for use on crops in the US (1).
A Norwegian study of a large population of rural residents found that pesticide use was associated with cancer in young children of less then five years of age (2). Participation in horticulture and pesticides use was also associated with Wilms tumor, non-Hodgkin’s lymphoma, retinoblastoma (eye cancer), and neuroblastoma.
Two recent reviews have analyzed studies of pesticide exposure and cancer in children. Sheila Zahm and Mary Ward reviewed 18 studies (1). Of these, 17 were case-control studies.
Most research has focused on the most common kinds of cancer in children – leukemia and brain cancer.
Most of the studies of pesticide exposure and leukemia show increased risks for children whose parents used pesticides at home or worked at jobs that required pesticide use (1). Some of the highest risks were when mothers were exposed to pesticides at work (3).
For brain cancer, the majority of relevant studies reported increased risk associated with pesticide exposure (1). The highest risks were associated with use of pesticides in the home or garden. Most studies reported that risks were higher for prenatal exposure.
For non-Hodgkin’s lymphoma, though there are fewer relevant studies, the results do suggest that pesticide exposure may be linked to the disease in children (1). One study found increased risk for children born to mothers who used pesticides in the home and for children living him homes where extermination had been done (3).
There is some evidence linking pesticide use to Wilms tumor and Ewings sarcoma (1).
Other forms of childhood cancer have received even less study.
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1. Zahm SH, Ward MH. Pesticides and childhood cancer. Environmental Health Perspectives 1998; 106 Suppl 3:893-908.
2. Kristensen P, Andersen A, Irgens LM, Bye AS, Sundheim L. Cancer in offspring of parents engaged in agricultural activities in Norway: incidence and risk factors in the farm environment. International Journal of Cancer 1996; 65:39-50.
3. Buckley JD, Robison LL, Swotinsky R, Garabrant DH, LeBeau M, Manchester P, Nesbit ME, Odom L, Peters JM, Woods WG, et al. Occupational exposures of parents of children with acute nonlymphocytic leukemia: a report from the Childrens Cancer Study Group. Cancer Research 1989; 49:4030-7.