Tufts University researchers who recently published a study in Environmental Health Perspectives linking bisphenol A (BPA) to mammary gland cancer in rats have walked back their claims after Forbes reported that the statistical data cited in the results "clearly showed BPA had no effects and did not cause cancer." Nicole Acevedo, et al., "Perinatally Administered Bisphenol A as a Potential Mammary Gland Carcinogen in Rats," Environmental Health Perspectives, September 2013. When first published ahead of print, the study in question apparently concluded that "developmental exposure to environmentally relevant levels of BPA during gestation and lactation induces mammary gland neoplasms in the absence of any additional carcinogenic treatment." The researchers also noted that human-relevant doses of BPA "led to the induction of malignant mammary gland tumors and other lesions in adult female rats."
But Forbes, after consulting with experts at the Bioinformatics at the National Institute of Statistical Science, argued that the evidence touted in the study was in fact random and could be ascribed to chance. "There is no dose response for cancer, which is their claim," the institute’s assistant director, Stanley Young, told Forbes. "The observed results given in Table 4 are consistent with chance."
As a result of these critiques, the study’s authors toned down the claims in the printed version of their work, writing instead that BPA "was associated with" the induction of malignant gland tumors and other lesions in adult female rats. "And to add insult to the injury done to science, Environmental Health Perspectives accompanied the article with a journalistic piece commenting on the significance of the study, which made not one reference to the actual statistical data," opines Forbes contributor Trevor Butterworth. "It is difficult not to see the heavy hand of an agenda at work here—one which seeks to indict BPA no matter what the data says." See Forbes.com, July 30, 2013, and September 26, 2013.