OCFP pesticide study triggered by complaint

The Ontario College of Family Physicians' conclusion that there are no safe pesticide exposure levels, which garnered unprecedented national coverage, was sparked by a pesticide industry lobby group's insistence that there is not enough evidence to support such warnings.

Figure. A pesticide-free Ontario garden. Photo by: Barbara Sibbald

The OCFP launched an extensive review of pesticide literature more than 18 months ago after Industry Task Force II on 2,4-D Research Data, a US-based group, complained that warnings of harmful effects of pesticides included in an OCFP information pamphlet were inaccurate. (2,4-D is the most common active ingredient in lawn care herbicides.)

The complaint was a repeat of the usual arguments in the ongoing debate on pesticides, which the head of the OCFP describes as “an exercise in finger pointing,” where one group cites a report warning of health effects and the other side cites another report indicating the results are inconclusive. The OCFP study was aimed at ending such discourse.

The study (www.ocfp.on.ca), funded by the non-profit Laidlaw Foundation, was not peer-reviewed or published. This is the first time a Canadian medical association has attempted to review the literature. Researchers examined 12 000 studies on the health effects of pesticides and drew conclusions from the 250 studies deemed to have the most solid methodology.

The review found “consistent evidence” of serious health risks, including brain, kidney, and prostate cancer, and reproductive and nervous system effects. For example, 3%–7.7% of cases of non-Hodgkin's lymphoma are attributable to exposure to phenoxyacetic acids and chlorophenols.

In addition, there was no evidence that some pesticides are less damaging than others. Rather, what differed were the effects and the time it took for them to appear.

“Our study showed that family doctors are right in advising patients to avoid exposures,” says Jan Kasperski, CEO of the OCFP.

But Donald Page, Executive Director of the Industry Task Force II, attacked the findings in the media and online, charging that the conclusions are based on a “biased review” with unclear criteria for study selection. — Pauline Comeau, Ottawa