Hot on the heels of a previous study from Exeter University in England mining a massive U.S. database of health information for associations between chemicals and disease, comes a new study by the same researchers that exposure to PFOA – Perlurooctanoic Acid, a precursor chemical to Teflon, is associated with
Clive Cookson, one of the best science journalists writing in English (one of the dwindling number of science journalists writing in English, alas), notes in the Financial Time, that one should not read too much into the findings:
“Independent experts urged people to treat the report with caution. Although the link found by the Exeter researchers seemed significant – people with the highest 25% of PFOA concentrations were more than twice as likely to report current thyroid disease than those with the lowest 50% of PFOA – many “confounding factors” might have caused the association.
Much more research will be needed to show whether or not there is a causal link.”
As STATS noted with the previous Exeter study linking heart disease to BPA, cross-sectional studies — snapshots of the apparant relationship between two factors made at a discrete point in time — are blunt scientific instruments, incapable of determining causality, not least because disease develops over time and levels of the chemical over the same time may vary considerably.
Environmental Health Perspectives rushed the abstract of this paper into print, a move which means omitting full discussion of the methodology and the limitations. Cynics might interpret that as a marketing strategy to maximize the news effect, while minimizing journalistic scrutiny. Even if that wasn’t the intention, it was certainly the outcome to judge by some of the other media coverage.