TABLE 2

Meta-Analysis Using Random Effects Model for the Relationship Between Childhood Cancer and Exposure to Residential Pesticides During Childhood

SubgroupStudy NSummaryHeterogeneity
OR95% CIPI2
Indoor pesticidesa,b
(A) AL61.591.40–1.80.8390
 Add professional home treatment71.551.38–1.75.7940
 Indoor insecticides51.591.39–1.81.7250
(B) Leukemia81.481.29–1.70.26720
 Add professional home treatment91.461.29–1.65.32713
 Dose and multiple agents effectsc31.921.27–2.89.9590
 Professional treatment only32.04*1.05–3.95.06164
 Indoor insecticides71.471.26–1.72.19730
(C) Lymphoma41.431.15–1.78.5780
 Indoor insecticides41.431.15–1.78.5780
(D) Hematopoietic cancers121.471.33–1.62.4570
 Add professional home treatment131.461.32–1.60.5130
 Indoor insecticides111.461.31–1.63.3885
 Dose and multiple agents effectc42.041.40–2.97.8940
(E) CBTsd,e,f41.220.83–1.81.27523
 Add professional home treatment51.110.87–1.42.3805
(F) All cancersf,g201.401.28–1.52.3905
Outdoor pesticidea,b
(A) Leukemia61.150.95–1.38.19033
 Herbicide51.261.10–1.44.7620
 Yard insecticidesh31.110.60–2.05.00284
(B) Lymphoma40.860.62–1.19.13147
 Herbicide31.52*1.02–2.27.09058
 Yard insecticidesi21.120.78–1.59.3142
(C) Hematopoietic cancers101.040.88–1.23.08641
 Herbicide81.331.16–1.52.35010
 Yard insecticides51.090.75–1.58.00771
(D) CBTs30.950.47–1.89.01277
 Herbicide21.980.94–4.14.4090
 Yard insecticidesj21.290.86–1.92.5480
(E) All cancersg161.100.93–1.32.00162
 Herbicide121.351.16–1.55.22123
 Yard insecticidesk81.140.89–1.45.02855
  • * The summary ORs became not statistically significant in the sensitivity analysis when we removed ill-defined herbicide or highest weight or extreme ORs. Study N: number of studies included. Hematopoietic cancers include leukemia and lymphoma. All cancers include neuroblastoma and Wilms tumor and soft tissue sarcomas in outdoor pesticides. Study results with case numbers <3 are not included in the summary.

  • a In the study35 where insecticides against different types of nuisance were reported, data with the highest OR were used.

  • b In the studies where results of different exposure windows in the same study were reported, the windows away from birth were used.

  • c The data of >10 per year were used in the study,38 and the data of >5 per year were used in the study.37

  • d When both cancer-free controls and cancer controls were reported, cancer-free controls were used.

  • e The crude OR and 95% CI were calculated based on the data in the article.42

  • f Where >1 home pesticide usage was reported, home pesticides for nuisance pests were used.

  • g In the study30 where the results were essentially the same during pregnancy and during childhood, the data reported from pregnancy through childhood were treated as during childhood.

  • h Includes studies35,39,41 and ORs associated with yard pesticides were replaced by yard insecticides in studies.35,39

  • i Includes 2 data from the study.41

  • j Includes 2 studies.32,40

  • k In addition to all yard insecticides in each subgroup, an additional study30 was included and ORs associated with yard pesticides were replaced by yard insecticides.