STATS ARTICLES 2008
Dishonest or Stupid? Either Way, PBS' NOW is a Journalistic Disgrace
Rebecca Goldin, Ph.D. March 27, 2008
Don’t let the facts get in the way of scaring the public – in fact, let’s just leave them on the cutting room floor
(errata appended April 1) .
I love PBS, and have always felt that it’s a great source for independent and in-depth reporting. That is, until I was recently interviewed for its show NOW on the subject of phthalates, a chemical substance used in plastics, and babies’ toys.
STATS has done a lot of work on the question of whether phthalates are safe or not, and we closely followed the research of several individual researchers as well as national and international scientific bodies whose job was to evaluate these products. We do not claim that phthalates are safe, but the evidence that they are “unsafe” (at normal exposure levels) is weak and inconclusive. In the interview I had with PBS, we discussed many aspects of the science behind phthalate safety research. None of these aspects were quoted or discussed in the final version that aired. As a matter of personal frustration with a topic being so poorly treated after spending so much time with the producers at NOW, I feel it’s worth mentioning what wasn’t in PBS’s show.
- The National Toxicology Program of the National Institutes of Health has convened several panels to evaluate the evidence for safety and determined that most phthalates pose little risk to humans at current exposure levels. The goal in these panels is to figure out how much is too much – in other words, how much exposure to phthalates will have a measurable, negative effect on humans. The conclusions are based on all the evidence coming from humans, rats, guinea pigs, and any other animal or laboratory experiments that can shed light on this question. The NIH determined current levels of human exposure to most phthalates pose low risks, but are worthy of future research. These panels did take into consideration the paper published by Dr. Shanna Swan that PBS touted as showing that phthalates are dangerous. The panels ultimately determined that her evidence wasn't strong enough to be wholly convincing, especially considering other research that has been conducted. There is one phthalate -- DEHP -- that a panel considers possibly to pose a risk to sexual development to infants; the panel notes that direct evidence has not yet surfaced but the animal evidence is very strong (see the NTP brief); this particular chemical was not shown to correlate with adverse effects in Swan's research (she checked three metabolites of DEHP and correlated none with reduced AGI). DEHP is not used in toys intended for children under 3, though it is used in toys generally. Some phthalates have been given more attention than others by these panels, particularly DINP which has been tested and retested without any evidence of adverse effects (and is used in toys intended for children under 3). The overarching theme among these highly-correlated chemicals is that we have little evidence to suggest adverse effects from current exposure levels to humans, and even less that the route would be through toys. I discussed the conclusions of the expert panels with PBS (though not phthalate-by-phthalate), but the conversation was directed toward Swan's research. This brings me to the next missing item.
- Scientific conclusions are drawn from all the research, not just one or two studies. There are good reasons for this – when a p-value of less than .05 make a study valid, there’s as much as one in twenty possibility that a study is measuring something that just happened to be an anomaly. There has to be a mechanism, and reproducible, consistent results pointing in one direction before it is accepted as a scientific conclusion. That is exactly the point of an expert panel – to weigh the evidence from many different studies, not just one. There have been hundreds of studies on phthalates, and some have come to different conclusions than Dr. Swan’s study. For example, while PBS pointed to possible fertility problems based on Swan’s study (which didn’t assess fertility) and based on consistent rat research (at much higher doses), a 2004 study found that premature baby boys who were exposed to extremely high levels of phthalates due to medical tubing had no decrease in fertility at all when they hit puberty. These levels were thousands of times higher than typical exposure rates. This research, like Swan’s, is just one study. The evidence has to come together to make a coherent picture. In the interview I discussed the importance of looking at the evidence as a whole rather than one article on the topic (and mentioned the study on premature babies as means of illustrating the point), but instead I was only asked to express my opinion about Swan’s work. No other research was mentioned in the PBS show.
- Swan’s results are not wholly convincing. Swan correlated a “total phthalate score” with “decreased anogenital index, (AGI)” which, in rats and at much higher levels, is a precursor for reduced fertility and genital problems in offspring. However, the human analog to the rat AGI is anoscrotal index – and Swan did not find a correlation there (she did check it). In addition, four of the phthalates – including DEHP which is the typical culprit found in toys – were not correlated with decreased AGI. Much of what Dr. Swan saw was “trends” rather than a “slam dunk” proof. In the NOW interview, I discussed the lack of finding with the anoscrotal index and the how the AGI has not been established to be biologically relevant, but the only part that aired was when I said that “Swan did find something.” I stand by that fact – I think human studies are extremely important and her work suggests that there could be a problem with human exposure that has, until now, gone unmeasured. But there are some important questions about the validity of her work, which, in the least, suggests a modicum of caution in reporting and concluding that phthalates are unsafe.
- The European Union’s ban on the use of phthalates in toys was implemented against the advice of its own scientific advisory committee. In a report by the EU's Scientific Commission, DINP and DIDP were determined not to pose any risk to humans and children under normal use. PBS neglected to tell those watching the program that the decision by the EU to ban toys was political in nature. European scientists did not come to a different conclusion than American scientists (nor were their decisions based on American research demonstrating risk, as suggested by Mark Shapiro). When I was quoted as saying “we teach our children not to jump off a bridge if their friends do,” it followed an un-aired disussion of how the Europen Commission found that phthalates in toys did not pose a risk. I was referring to the difference between banning these substances because the EU does, versus banning these substances because the science says it’s the right thing to do.
- Banning phthalates in toys will have little effect on children’s development. Most of our phthalate exposure comes from food and air – phthalates are not in bottle nipples or pacifiers, which are the main plastics that babies suck on. Most of the exposure that children are getting from phthalates are from medical treatment if they need it (such as intravenous tubing), our food, and the dust we breathe. I mentioned this to the producers who said that they planned to ask Dr. Swan about this issue – apparently, if she made the same point, it went un-aired.
- STATS has no funding or formal relationship with the Phthalates Esters Panel. Perhaps this was an attempt to discredit our research, but NOW mentioned that my research appears on the Phthalates Esters Panel website. Anyone at all can quote our work, or link to our work at STATS, including PEP and PBS. All research at STATS is funded by foundational money, not industry interest groups. We have no particular interest in defending the plastics industry, I was not asked to write for PEP, and my research is not posted on the PEP site; it is simply linked there from our own site, www.stats.org.
The overall feeling I got from watching PBS’s NOW program is that either the PBS producers were dishonest in their intentions (and never actually wanted to hear more than one side of the science behind phthalates) or they are incapable of understanding what a scientific argument is about. To go from a discussion of the scientific nature of a controversial chemical to a one-sided presentation by a single scientist on the issue is a major misstep in the important work of providing the public with a view of what’s really going on. PBS has contributed to continuing fear-mongering on this issue, without providing their viewers with even an opening to look at the issue critically.
Dr. Rebecca Goldin is Director of Research for STATS. She is Associate Professor of Mathematical Sciences at George Mason University, and a member of the Science Policy Committee of the American Mathematical Society. She holds degrees from Harvard and MIT, and last year she was the first recipient of the Ruth I Michler Memorial Prize, which honors outstanding young women in the field of mathematics. Dr. Goldin has advised numerous news organizations on statistical analysis. Her work for STATS is partially supported by the National Science Foundation Grant 0606869. (Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.)
Editor’s note. Mark Shapiro, whose book 'Exposed: The Toxic Chemistry of Everyday Products' formed the basis of the NOW program wrote an entry on the Huffington Post repeating many of these errors and adding some new ones. Trevor Butterworth, who also contributes to the Huffington Post, wrote a response to these errors.
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