Occupational exposure to pesticides and risk of hematopoietic cancers: meta-analysis of case-control studies

• Published in: Cancer causes & control Vol. 18; no. 10; pp. 1209 - 1226
• Main Authors: Merhi, M, Raynal, H, Cahuzac, E, Vinson, F, Cravedi, J. P, Gamet-Payrastre, L
• Format: Journal Article
• Language: English
• Published: Netherlands Dordrecht : Springer Netherlands 01.12.2007; Springer; Springer Nature B.V
• Subjects: Agriculture; Cancer; Case control studies; Chemical hazards; Epidemiology; Farmers; Female; Hematologic Neoplasms - chemically induced; Hematologic Neoplasms - epidemiology; Hematopoietic cancers; Humans; Leukemia; Lymphoma; Lymphoproliferative Disorders - chemically induced; Male; Meta analysis; Meta-Analysis as Topic; Models, Statistical; Multiple myeloma; Myelodysplastic syndromes; Non Hodgkin lymphoma; Occupational Exposure - adverse effects; Pesticides; Pesticides - toxicity; Professional exposure; PubMed; Retrospective Studies; Risk Factors; Tumors
• ISSN: 0957-5243; 1573-7225
• DOI: 10.1007/s10552-007-9061-1

Objective In this study we conducted a meta-analysis of 13 case-control studies that examined the occurrence of hematopoietic cancers in pesticide related occupations in order to undertake a qualitative and quantitative evaluation of a possible relationship. Methods Pubmed databases were searched for case-control studies published between 1990 and 2005 investigating the relation between hematopoietic cancers and occupational exposure to pesticides. Fixed and random effect meta-analysis models were used depending on the presence of heterogeneity between studies. Results The overall meta-odds ratio obtained after pooling 44 ORs from 13 studies was 1.3 (95% CI: 1.3-1.5). We realized stratified analysis on three different types of hematopoietic cancers (non-Hodgkin lymphoma (NHL), leukemia and multiple myeloma). A significant increased risk of NHL was found (OR = 1.35; 95% CI = 1.2-1.5). Moreover, increased risks of Leukemia (OR = 1.35; 95% CI = 0.9-2) and multiple myeloma (OR = 1.16; 95% CI = 0.99-1.36) were also detected but these results were not statistically significant. Significant heterogeneity existed among the different studies and a publication bias was detected. Therefore, a meta-regression was carried out. Our results showed that a long period of exposure (more than 10 years) provided an increase in the risk of all hematopoietic cancers and for NHL by fractions of 2.18 (95% CI = 1.43-3.35) and 1.65 (95% CI = 1.08-2.51), respectively. Conclusions: The overall meta-odds ratio suggests that there is a significantly positive association between occupational exposure to pesticides and all hematopoietic cancers as well as NHL. A major limitation of our meta-analysis is the lack of sufficient data about exposure information and other risk factors for hematopoietic cancer (genetic predisposition, ethnic origin, immunodepression[em leader]). In addition, data concerning specific subtypes of hematopoietic cancers are often confusing. Thus, future epidemiological studies should undertake a major effort to assess the identity and the level of pesticides exposure and should control for the most likely potential confounders.