Stop worrying and learn to love the chemicals

Well Margaret Wente is at it again. In a column last week titled Yellow duckies and other killers, she claims that "Mothers across Canada have been prostrated by the plastics scare."

It's hard to be a good mother these days. Deadly perils lurk everywhere. Take that yellow bathtub ducky, contaminated with a dangerous substance known as BPA.

But why stop there? Wente proceeds to list other putative hazards: toxic mould, pesticides, perfumes, "death-rays from the sun", walking barefoot in the grass. The message is clear: stop worrying already!

We forget how negligent our own parents were. They gave us naked sunbaths and let us suck on plastic duckies and roll around on pesticide-drenched lawns. It's astonishing how ignorant they were, and how many of us managed to grow up.

Now Margaret Wente is no scientist (what was your first clue?), so she needs an outside authority:

Dr. Elizabeth Whelan is president of the American Council on Science and Health [ACSH], an independent group devoted to accuracy in health reporting. She points out that both BPA and phthalates have been studied intensively for decades. There are no studies - none - that show any link between these substances and harm to people. The basis for the claims of danger are all from studies done on rats, and they don't predict human risk.

According to Media Transparency, ACSH haven't disclosed their corporate donors since the early 1990's, but their 1991 annual report listed each of the following as contributing at least $15,000:

American Cyanamid Company * Anheuser-Busch Foundation * General Electric Foundation * Rollin M. Gerstacker Foundation * ICI Agricultural Products, Inc. * ISK Biotech Corporation * Kraft, Inc. * Monsanto Fund * The NutraSweet Company * John M. Olin Foundation, Inc. * Pfizer, Inc. * Sarah Scaife Foundation Incorporated * The Starr Foundation * Archer Daniels Midland Company * Carnation Company * Ciba-Geigy Corporation * Ethyl Corporation * Exxon Corporation * General Mills, Inc. * Heublein Inc. * Hiram Walker-Allied Vintners * Johnson & Johnson * Kellogg Company * The Esther A. and Joseph Klingenstein Fund, Inc. * Malaysian Palm Oil Promotion Council * National Starch and Chemical Foundation, Inc. * PepsiCo Foundation Inc. * Union Carbide Corporation

The under-$15,000 list continues on, listing all kinds of industrial, pharmaceutical, and food corporations.

Figures don't lie ...

In her April 19th column, Wente quoted an organizations called the Statistical Assessment Service (STATS) who similarly dismiss concerns about BPA. While they don't accept industry money, STATS is funded by a number of the same conservative organizations as ACSH. I think I see a pattern here.

But so what if these organizations get "conservative" funding? An anonymous commenter on my previous post wrote:

Why should the funding source matter? Isn't it the quality of the evidence and the arguments made? Your smear is the equivalent of an ad hominem attack.

My response:

I don't think it's ad hominem. If a medical study was funded by a pharmaceutical company, I'd like to know that. Not that it invalidates the study: as you say, the quality of the evidence and the arguments (analyses) made is centrally important.

So let's have a closer look at the quality of the evidence and arguments in one particular case.

I looked at a recent post on the STATS blog concerning formula- versus breast-feeding. While the author allows that "Yes, there is robust evidence that nursing reduces ear infections [otitis media] and diarrhea", he sets out to discredit claims of a link between formula feeding and diabetes, leukemia, and serious respiratory infections. In the latter case, he writes "The most recent research does not support the contention that formula carries a higher risk," citing a 1995 paper from the Journal of Pediatrics.

Interestingly enough, that study was supported in part by the Mead-Johnson Nutritional Group. Leaving that aside, however, here are some results from the abstract:

In the first year of life the incidence of diarrheal illness among BF [breast fed] infants was half that of FF [formula fed] infants; the percentage with any otitis media was 19% lower and with prolonged episodes (>10 days) was 80% lower in BF compared with FF infants. There were no significant differences in rates of respiratory illness; nearly all cases were mild upper respiratory infections. ... These results indicate that the reduction in morbidity associated with breast-feeding is of sufficient magnitude to be of public health significance.

Sure enough, they didn't find statistically significant differences in rates of respiratory illness. Now an important consideration in statistics is the power to detect differences, which is determined by a number of factors including sample size. So what was the sample size in this study?

... morbidity data were collected by weekly monitoring during the first 2 years of life from matched cohorts of infants who were either breast fed (N = 46) or formula fed (N = 41) until at least 12 months of age.

So there were a total of 87 infants. In their discussion, the authors write:

We did not observe any significant differences in the incidence or prevalence of respiratory illnesses between BF and FF infants. However, the vast majority of episodes were mild upper respiratory illnesses. Previous studies have indicated that the protective effect of breast-feeding is greatest for lower respiratory illnesses. The sample size in our study was not large enough to detect differences in more severe respiratory illnesses.

Blind trust?

Ultimately, we all have to rely on some surrogate measures to judge the quality and trustworthiness of the information we encounter. Our own expertise can only be so broad and we rely on others to help us interpret the world. Oldly enough the words of Ronald Reagan come to mind: "Trust, but verify."