A new study is alleging a link between pesticide use in agriculture and Type 2 diabetes.
“This systematic review supports the hypothesis that exposure to various types of pesticides increases the risk of diabetes,” said the study’s authors, Giorgos Ntritsos, Dr. Ioanna Tzoulaki, and Dr. Evangelos Evangelou, with the University of Ioannina, Greece, and Imperial College London, UK, respectively.
A meta-analysis of 21 studies presented last week at this year’s annual meeting of the European Association for the Study of Diabetes 2015 found exposure to pesticides significantly increases the risk of Type 2 diabetes by as much as 61 percent.
However, some find the claim of exposure to pesticides through food consumption highly implausible.
“There are a number of conceptual flaws in this study,” said Dr. Henry Miller, a Robert Wesson fellow in scientific philosophy and public policy at the Hoover Institution at Stanford University in California. “‘Pesticide’ is an ill-defined category — really a pseudo-category — because it goes to intent, rather than to any particular compositions of matter.
“Depending on the definitions in statute and regulations, a ‘pesticide’ can be anything from a fly swatter to a chemical or bacteria. And even if we’re talking about only chemical pesticides, they act via a spectrum of very different mechanisms, making meta-analysis-based generalizations about ‘increased risk’ problematic.”
The data also indicate that different types of pesticides may pose a greater risk than others.
“There are a number of conceptual flaws in this study,” said Dr. Henry Miller, at the Hoover Institution at Stanford University in California.
Miller said the meta-analyses — a statistical technique for combining the findings from independent studies — are subject to a high degree of unreliability, depending on how the included studies are selected, and the methodology used.
“Even in the best of circumstances, an increase in risk of 61 percent determined by a meta-analysis is unlikely to be reliable — that is, ‘real,’” Miller added.
Inspired by Pharmacology?
Complicating the study outcomes, the European Association for the Study of Diabetes has a lengthy list of corporate pharmaceutical members including Merck, Novartis, AstraZenecca, Eli Lilly & Co., Janssen Pharmaceutica NV of Belgium, Abbott Laboratories, Takeda Pharmaceuticals, Pfizer, Sanofi, and BD Medical Diabetes Care.
Within days of announcing the study at the EASD, numerous medical periodicals were reporting on the findings as if the science was settled. That came despite the study authors’ disclosure statement at the end of the forum that further studies would be needed to better understand “the pathophysiological mechanisms underlying the links” to diabetes with pesticides, Medscape reported. The study team is performing further analyses to assess whether body-mass index has a confounding effect on the findings.
“The amount of pesticides ingested by the public is so small that in view of the background of possible causes of disease, pesticides make no toxicological sense at all,” said Bruce N. Ames, a senior scientist at Children’s Hospital Oakland Research Institute.
“But scientists occasionally ‘go rogue,’ forsaking the scientific method — often for notoriety or economic gain — to produce propaganda and to sow fear in (the) public.”
“We have an epidemic of diabetes caused by people eating terrible diets and becoming obese. The obese are eating about the worst diet in the country, as defined by ratio of essential items in the diet (vitamins, essential minerals, fiber, etc.) relative to empty carbohydrate and fat calories. Every possible disease of aging including Type 2 diabetes, cancer, brain decay, immune decay, heart disease, is accelerated in the obese. Trying to blame a significant amount on pesticides isn’t plausible, is a disservice to the poor, and a distraction in solving the problem,” Ames said.
Pesticides and Organic Agriculture
There are more than 20 chemicals commonly used on organic crops, approved by the U.S. Organic Standards.
“Organic standards arbitrarily define which pesticides are acceptable, but allow ‘deviations’ if based on ‘need.’ Synthetic chemical pesticides are generally prohibited, although there is a lengthy list of exceptions in the Organic Foods Production Act, while most ‘natural’ ones are permitted (and the application of pathogen-laden animal excreta as fertilizer is allowed). The decisions are made in a murky process that combines agronomy, lobbying, and fundamentalism,” Miller said.
The Politics of Science
“Science enables us to gauge what we think we know and to identify what we do not,” Miller said in commentary published in Project Syndicate. “Most important, it discredits false claims made for personal or political reasons — at least it should. But scientists occasionally ‘go rogue,’ forsaking the scientific method — often for notoriety or economic gain — to produce propaganda and to sow fear in a public that lacks expertise but is hungry for information.”
This latest analysis has fed that fearful, hungry public a load of bunk — whose only effect will be to push consumers toward higher-priced organics, or worse, discourage them from eating the vegetables they should.