A new study from a team of researchers at the University of Michigan has generated quite a bit of media attention this week. The researchers set out to examine if there was a link between BPA and other chronic diseases such as obesity and diabetes. The team used nutrition survey data from 3,370 kids to compare BPA levels in the urine of 6- to 18-year-olds. In their analysis, BPA was not linked to insulin resistance or blood sugar, but the authors of the study concluded that children with higher BPA levels were more likely to be obese. As soon as the study was released, articles began to appear in a number of publications, including Reuters and La Razón is Spain, which wrongly asserted that “BPA causes obesity”.
Despite these sensational headlines, the study does not in any way prove that BPA causes obesity. It merely observes a statistical correlation between children with higher BPA levels and childhood obesity. And as I’ve cautioned before, we need to remember that correlation does not equal causation.
Actually, the researchers themselves admit that this study does not provide evidence that BPA exposure causes childhood obesity. They write that, because BPA is rapidly excreted by the human body (within 24 hours) and obesity occurs over time, studies like this one, which merely take one measurement of BPA from a urine sample, cannot provide proof of causation between BPA and obesity.
It is also worth noting that the study was also accompanied by an editorial commentary by Dr. Robert Brent, who argues against the conclusions drawn from the research and further emphasizes that the type of food consumed has a much more significant effect on obesity than dietary exposure to certain substances like BPA. Unfortunately this commentary, which provides a useful reference to studies largely ignored in the paper, was hardly reported in the media. This is unfortunate as this type of commentary shows science in action – Researchers test a hypothesis and present research and fellow scientists challenge their findings and conclusions.
More research should certainly be done to better understand this issue, but we need to remember that there are many things known to cause obesity and they often involve lifestyle choices like poor diet and lack of exercise. It’s great to see researchers weighing evidence and challenging research. And while I wish the media would provide more context when reporting on scientific studies, I also encourage all of us as individuals to go beyond what’s just reported in the media. Seeking more information on controversial subjects like BPA will empower people to weigh the arguments and make their own, informed decisions. This is an essential step in moving the debate on BPA forward, beyond sensational headlines, and toward productive discussions about BPA.