Landfill Study Was Pure Garbage
When the British Medical Journal published as study claiming to find a linnk between birth defects and living near landfills, the BBC quoted anti-landfill activist Natalie Medlicott as saying, “It shows taht we were right all along.” In reality the actual conclusion to draw from teh study is that there it demonstrated there is no evidence of any link between landfills and birth defects.
Follow the bouncing ball here. Epidemiological studies are rather crude tools for a variety of reasons. To really say there is a likely causal link between two variables, such as landfills and birth defects, ideally there should be a very large relationship on the order of 200 percent. Otherwise, the odds are very high that the result is just a product of statistical noise. This is why, for example, studies finding a 20 to 30 percent increase in the risk of cancer among women who have had abortions are routinely dismissed — that level of risk is simply too low to measure with standard epidemiological tools.
So how big is the alleged risk from living near landfills? According to the BMJ study, it is a whopping one percent. That’s right, the BMJ actually published a study claiming that there was a one percent higher risk of congenital abnormalities for people loiving within 2 kilometers of a landfill site, a 7 percent higher risk for those living near sites containing hazardous waste, and a 5 percent risk of low birth weight for babies born to parents living near landfills.
These results are so low that this is largely the same thing as saying the study found no evidence of any increased risk from living near landfills. That the BBC and other news media chose to spin these studies as finding a serious link between birth defects and landfills was absurd.
The BBC did quote experts to that effect in its story, with Professor Charles Rodeck telling teh BBC, “I am greatly reassured by it [the study]. If a woman said to me ‘do I have to move away’ I would say no.” But it also included plenty of sensationlist quotes such as that from Friends of the Earth’s Mike Childs saying, “This study adds to our fears that if youa re born near a landfill sit eyou are more likely to be born with a birth defect.”
And most importantly, nowhere in its study does the BBC explain anything about statistics and epidemiological studies that might allow readers to better understand what a 1 percent increased risk in an epidemiolgoical study really means.
Source:
Birth defect link to landfill sites. The BBC, August 16, 2001.
Living in the shadow of a landfill. The BBC, August 16, 2001.
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