Chronic exposure to chlorophenol related compounds in production workplace and kidney cancer: A meta-analysis

Chlorophenols are a group of pesticides contaminated with dioxin compounds during their manufacturing. The International Agency for Research on Cancer (IARC) demonstrated an association between dioxin exposure and lung cancer, non-Hodgkin lymphoma, and soft-tissue sarcoma but the risk of kidney cancer and dioxin exposure has not been clearly defined. This study was proposed a meta-analysis of published researches to evaluate relationship between chronic chlorophenols exposure in pesticide production workplace and the mortality risk of kidney cancer. ″chlorophenol″, ″Phenoxyacetic acid″, ″cancer″ and ″dioxin″ keywords were used in PubMed, Embase, Science Direct, Ovid, Google Scholar, and Medline until 2012 and all publications that investigated the association between chroniccholophenols exposure in the production workplace and kidney cancer were identified. Publication bias was evaluated based on Egger test and funnel plot. We evaluated the heterogeneity of the studies with Q test. Random-effects model of DerSimonian Laird method was conducted in heterogenic studies, otherwise fixed-effects model based on Mentel-Henzel random effects model was used. Our search yielded 27 papers which investigated the association between chronic cholophenols exposure in the production workplace and cancer. After reviewing these papers 7 publications without overlapping represented standardized mortality rate (SMR) of kidney cancer. Results of metaanalysis showed that SMR for kidney cancer in workers with cholophenols exposure was increased (SMR: 1.25, 95% CI: 0.9- 1.63, p = 0.09). The results of this study strengthen the evidence of cancer in occupational exposure to cholophenols contaminated with TCDD. Moreover, these compounds increased the risk of death from kidney cancer which was related to the type of cholophenols compound and dioxine contamination.