Meta-analysis connects glyphosate with non-Hodgkin lymphoma
Schinasi and Leon (2014) performed a meta-analysis of 44 studies on the relationship between non-Hodgkin lymphoma (NHL) and occupational exposure to 80 agricultural pesticide active ingredients, including glyphosate. A meta-analysis is a method that focuses on contrasting and combining results from different studies, in the hope of identifying patterns among study results, sources of disagreement among those results, or other interesting relationships that may come to light in the context of multiple studies. The study claims that glyphosate exposure was positively associated with NHL, and particularly B cell lymphoma. However, this claim is not substantiated by the information put forth in this paper. Additionally, an extensive body of literature exists, demonstrating that glyphosate does not cause cancer, including NHL.
For instance, experimental evidence from multiple long-term studies with laboratory animals demonstrates that glyphosate is not mutagenic or carcinogenic. A potential source of errors in any meta-studies is publication bias, caused by the inclusion of smaller studies with smaller sample size and therefore less significant data. If given the same weight as larger analysis, this causes a significant bias leading to invalid conclusions.
Finally, no efforts were made by Schinasi et al. to assess the potential publication bias in this meta-analysis. It is reasonable to believe that this meta-analysis suffers from undue influence by smaller studies included in the meta-analysis leading to a bias of the results and false conclusions.
Last update: 27 May 2014