Pregnant women, beware …
…According to the media, anyway. This week, article after article warned pregnant women to avoid bisphenol-A (or BPA), a substance found in plastic bottles and canned foods that is used to harden plastic and prevent the spread of food-borne bacteria. The reason is a new study that purports to show that BPA exposure to fetuses in the womb can cause behavioral problems in toddler-age girls.
The study, which tracked 244 Cincinnati-area mothers and their three-year-olds, concluded that mothers with high levels of BPA in their urine were more likely to report that their children were hyperactive, aggressive, anxious, depressed or suffering from emotional problems than mothers with low levels of the chemical. Sound scary? Of course it does, especially to a pregnant woman who already has a long list of proscribed substances and behaviors.
What is largely missing from these stories, however, is the scientific context. Nearly all of the media stories about this study neglected to report scientific facts that would dramatically alter the conclusions to be drawn. The harsh truth is that the study is inherently flawed; its results are irrelevant to human health; and its conclusions about BPA’s effects are far-out speculations, if not simply incorrect.
The researchers seem not to appreciate the critical distinction between association and causation. Thus, they simply associated BPA levels in pregnant women with common behavioral disorders in their children without controlling for other factors that may also cause these same behavioral issues; thus, they cannot demonstrate cause and effect.
The study authors themselves acknowledge that their results could be due to chance and that any clinical relevance of their findings is “unclear.” On closer review, one finds that the authors failed to run appropriate tests to ensure that their results were even statistically significant — a hallmark of any properly executed laboratory research. In other words, even if the association exists – which itself is uncertain – it could result simply because BPA exposure is a sort of marker, or surrogate, for the real cause of the behavioral disorders.
The bottom line is that this study does nothing to inform us about our daily lives. It offers absolutely no reason to believe that BPA exposure is affecting the health or behavior of three-year-old girls. And yet the media headlines have never been scarier. Why? Is it because science reporters don’t actually understand the science? Maybe that’s true for some of them. Is it that activist groups are using flawed science and scare-tactics to exploit the media? Yes, definitely — but without the media’s collusion, their efforts would come to naught. In their effort to write sensational headlines, the media have repeatedly neglected the full story on BPA research.
Unfortunately, there is more than merely the failure to report scientific details of a study accurately. Reporters who have covered the BPA issue have not only done a careless job accurately explaining the body of scientific research but also have failed to report the other side of the story — voluminous research demonstrating that BPA is safe. A perfect example occurred a few months ago around the release of an EPA-funded study on BPA. In this study, government laboratory scientists in partnership with CDC and FDA conducted a human exposure study which found that because of the way BPA is processed in the body, it is nearly impossible that it could cause health effects in adults, children or even fetuses. This was unquestionably one of the most important studies ever conducted on BPA, and was performed by government scientific bodies, no less, but it elicited hardly a peep from the media.
I won’t pretend that there is no debate within the scientific community on this issue. Whether or not this debate is warranted is another question. (I believe it’s not). But regardless of my opinion, it is the media’s job to offer the public both sides of the story in a context that is both accurate and relevant to their daily lives.
Therefore, my plea to science journalists around the world is this: Studies on BPA from both sides need to be not only reported but also put into proper, real-world context for readers and viewers. Make an effort to understand the science and dig a little deeper, rather than just relaying activist propaganda to write your piece. Resist the attraction of, “if it bleeds, it leads.” On a topic such as this, in which there are significant negative implications to banning BPA, to do anything else is irresponsible science journalism.
Henry I. Miller, a physician and molecular biologist, is the Robert Wesson Fellow in Scientific Philosophy and Public Policy at Stanford University’s Hoover Institution. He was an official at the NIH and FDA from 1977 to 1994.