Systematic review and meta-analysis of cyclodiene insecticides and breast cancer

Cyclodienes are a group of organochlorine pesticides that have been the focus of increasing numbers of breast cancer etiology studies in recent years. The aim of this systematic review and meta-analysis was to summarize and pool the results of breast cancer and cyclodiene insecticide contamination studies. We used databases from 1966 to 7/2006 and included 21 case-control studies. Pooled odds ratios or differences in means as geometric means ratios were calculated. Meta-analysis of the chemicals did not reveal any statistically significant association except for heptachlor. The heterogeneity among the different studies and the methodology limitations are discussed.