Rationalizations to support claims that the chemical bisphenol A (BPA) poses a real and serious health threat have gone from dumb to dumber! Even reputable researchers make their case by regularly citing one inconclusive study to suggest another inconclusive study is meaningful. But science doesn't work that way.
Used to make hard, clear plastics and resins that line cans containing everything from soda to soup, BPA is a target of the greens who get plenty help from researchers who use creative rationalizations to spin their findings.
A recent example comes from one of the authors of yet another study on BPA using data from the National Health and Nutrition Examination Survey (NHANES). It suggests that BPA levels could contribute to heart and kidney disease. But reliance on NHANES data raises a host of questions about the study’s value, as explained in a prior post and in a peer reviewed paper detailing why it isn’t reasonable to draw conclusions from this data. Without even considering that serious defect, we can see from one of the researchers comments that the study isn't particularly compelling anyway. One of the study’s authors, Dr. Leonardo Trasande, explains in Science Daily:
While our cross-sectional study cannot definitively confirm that BPA contributes to heart disease or kidney dysfunction in children, together with our previous study of BPA and obesity, this new data adds to already existing concerns about BPA as a contributor to cardiovascular risk in children and adolescents.
In other words, the value of this latest study rests at least in part on the value of the prior study for which Trasande is also an author. This prior study appeared in the Journal of the American Medical Association last year that suggested BPA contributes to obesity, but, as I noted then, the authors say the findings are inconclusive. Specifically, Trasande and coauthors state within the JAMA study:
BPA exposure is plausibly linked to childhood obesity, but evidence is lacking to date ... This cross-sectional study, when considered in isolation, is at best hypothesis generating.
Why and how could a study with findings are “at best hypothesis generating” strengthen an “unconfirmed” finding of another study? Supposedly it can because the authors in the JAMA study maintain that it is more than “hypothesis generating” because of findings from yet another study. This one dates back to 2004, and it too is inconclusive, as I detailed in my post on the JAMA study.
Perhaps most telling of all are the studies that Trasnade and his colleagues don’t mention, including a recent rodent study that could not find an association between BPA and obesity. They also don’t mention an EPA-funded study that shows humans pass BPA quickly from the human body -- making it unlikely to have any impacts. Nor do they mention, the study questioning the underlying NHANES data.
In sum, ignoring evidence to the contrary, Trasade suggests that his latest inconclusive study is meaningful because of finding of the inclusive JAMA study, which is only made more than "hypothesis generating" because of the existence of yet another inconclusive study.
This very fishy line of reasoning really isn't about science. It’s about an agenda, as Trasnade explains in Science Daily:
It [his research] further supports the call to limit exposure of BPA in this country, especially in children ... Removing it from aluminum cans is probably one of the best ways we can limit exposure. There are alternatives that manufacturers can use to line aluminum cans.
While he may mean well, this advice is the more dangerous proposition because BPA resins are used to prevent the development of pathogens like E. coli in our food. Without it, many people could suffer from real kidney disease, and some could die.