November 4, 2024

expert reaction to study suggesting association between many pesticides and prostate cancer

A study published in Wiley Cancer looks at an association between pesticides and prostate cancer incidence. 

Prof Paul Pharoah, Professor of Cancer Epidemiology, Cedars-Sinai Medical Center, said:

“The epidemiological design used to evaluate the association between pesticides and prostate cancer incidence and mortality in this study is called an ecological study.  In an ecological study the unit of analysis is the population in a given area, and so the correlation studied is that between pesticide levels in a given area and prostate cancer rates in the same area.  It is important to note that pesticide exposures and prostate cancer occurrence in individuals was not studied.

“Ecological studies are very prone to bias and can give rise to the ecological fallacy – the assumption that group level correlation also applies to individuals.  Ecological studies are generally regarded as hypothesis generating rather than hypothesis testing.  The well-known mantra that correlation does not mean causation is particularly applicable to ecological studies.

“While several associations were identified, no data to suggest that these associations are causal is presented.  It is notable that of the four pesticides associated with both incidence rates and mortality rates of prostate cancer three are considered by the Environmental Protection Agency of the USA as not likely to be carcinogenic or have evidence of non-carcinogenicity.”

‘Pesticides and prostate cancer incidence and mortality: An environment‐wide association study’ by Simon John Christoph Soerensen et al. was published in Wiley Cancer at 08:01 UK Time Monday 4 November 2024. 

DOI: 10.1002/cncr.35572

Declared interests

Prof Paul Pharoah: I have previously provided expert testimony in for the defence in glyphosate and lymphoma litigation