in his garden
Researchers have linked residential pesticide exposure to childhood cancers, but the estimated risks vary according to the cancer type, the type of pesticide, and where it is applied.
The investigators conducted a meta-analysis of published studies and found that childhood exposure to indoor pesticides was associated with a
significantly increased risk of all the cancers analyzed, as well as leukemia and lymphoma individually.
Overall, exposure to outdoor pesticides was not associated with an increased risk of childhood cancers. However, herbicide exposure was linked to an increased risk of leukemia and all cancers combined.
Mei Chen, PhD, of the Harvard T.H. Chan School of Public Health in Boston, Massachusetts, and colleagues conducted this meta-analysis and reported the results in Pediatrics.
The team searched for observational studies published in PubMed before February 2014 and ultimately included 16 studies in their analysis.
They assessed exposure to indoor pesticides and indoor insecticides (a subgroup of indoor pesticides), as well as exposure to outdoor pesticides, which included outdoor insecticides, herbicides, and fungicides.
The cancer types analyzed were leukemia, lymphoma, brain tumors, neuroblastoma, Wilms tumor, and soft tissue sarcoma.
Indoor pesticides
When the investigators analyzed all cancer types together, they found a significantly increased risk of childhood cancers associated with exposure to indoor pesticides (odds ratio [OR]=1.40).
Likewise, there was a significantly increased risk for leukemia (OR=1.48), acute leukemia (OR=1.59), lymphoma (OR=1.43), and all hematopoietic malignancies (leukemias and lymphomas, OR=1.47).
But the increased risk of childhood brain tumors was not statistically significant, and the other cancers were not analyzed separately.
Exposure to indoor insecticides was associated with a significant increase in the risk of leukemia (OR=1.47), acute leukemia (OR=1.59), lymphoma (OR=1.43), and all hematopoietic malignancies (OR=1.46).
Outdoor pesticides
There was no significant association between exposure to outdoor pesticides or outdoor insecticides and any of the cancer types. And there were not enough studies on fungicides to assess the risk of cancers associated with their use.
However, there was a significant association between exposure to herbicide and all childhood cancers (OR=1.35) as well as leukemia (OR=1.26).
The investigators said these results suggest cancer risks are related to the type of pesticides used and where they are applied.
And although additional research is needed to confirm the association between pesticide exposure and childhood cancers, steps should be taken to limit exposure to pesticides during childhood.
