Literature review on epidemiological studies linking exposure to pesticides and health effects
We performed a systematic and extensive literature review of epidemiological studies examining the association between pesticide exposure and any health outcome published after 2006. We searched 43,259 citations and identified 603 published articles examining a very wide variety of outcomes and presenting over 6,000 analyses between pesticide exposure and health outcomes. We divided the different outcomes into 23 major disease categories. The largest proportion of studies pertains to cancer outcomes (N=164) and outcomes related to child health (N=84). The majority of studies were case-control studies and cross-sectional studies (N=222) and examined occupational exposure to pesticides (N=329). A wide and diverse range of pesticides was studied with studies using various definitions of pesticides; it is very hard to harmonise between studies this information. Despite the large volume of available data and the large number (>6,000) of analyses available, firm conclusions cannot be made for the majority of the outcomes studied. This observation is disappointing especially when one accounts for the large volume of research in the area. However, this observation is in line with previous studies on environmental epidemiology and in particular on pesticides which all acknowledge that such epidemiological studies suffer from many limitations and that the heterogeneity of data is such that does not allow firm conclusions to de made. We also performed updated meta-analysis for major outcomes and for those where a relevant meta-analysis published after 2006 was identified. This has only been possible for childhood leukaemia and for Parkinson’s disease. For both these outcomes we found significant associations between pesticide exposure and disease in line with previous evidence.