Friday, January 13, 2012

(Ir)rational approaches to decision-making...

I've recently attended a seminar where a highly enthusiastic young pediatrician was trying to convince the public that her research on environmental disruptors of the endocrine system during prenatal development is (1) interesting and important, and (2) can contribute to shaping policy in terms of child safety products regulations. What she is trying to figure out is whether certain types of chemicals, phtalens, which can be found in plastic products such as kitchen utensils and toys, as well as in foods rich in fat (cheeses, red meat), can cause developmental abnormalities in the reproductive system of boys. The reason to study this, according to her words, is to ask the question whether pregnant women should be advised to avoid such products and to eventually introduce regulations that will ban/set restrictions on phtalens content in products which are considered as safe for soon-to-be-born children and babies. At first sight, the idea does not seem unreasonable, but doubts start to rise when we pay more attention to the problem. Despite the concerns of methodological nature which I will not talk about, I don't see much sense in pursuing such studies. Let me explain why.
There's plenty of evidence that phtalens indeed can cause even severe developmental abnormalities in mammals.These findings are based on animal studies that involved higher doses of these compounds but even lower doses might be harmful. This makes them a potential threat for human well-being as well. Moreover, when people are exposed to phtalens, these do really get to our systems (we can detect phtalens metabolites in urine), so there's a chance that the fetus becomes exposed in the same way as its mom. However, in order to confirm their toxicity in humans, we will need to spend huge amount of money, time and resources. Clinical studies are very expensive, time-consuming and involve participation of many people.  This nation-wide clinical reasearch project has been supported by the NIH for seven years already. Still, at least half a decade remains until the final results and guidelines are established. Do we really need to devote all the financial, administrative and scientific resources to confirm a hypothesis that is most likely true based on current knowledge? Obviously, any safety regulations have to be conservative. Nobody will ignore animal studies and risk human health for several years.
There is a prallel heare between clinical drug trials and toxicity studies. Potential drugs that exhibit severe side-effects (like developmental defects) during pre-clinical trials are never tested on patients, let alone pregnant women. Do we really need to establish the exact toxicity of phtalanes, which are just pollutants of no medical use? We can extrapolate human toxicity from animal studies for conservative legislative decisions. This should be sufficient. Doesn't it sound rationally? 

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