Study links food-packaging chemical (BPA) and obesity in girls

[Redfairen]

Source: USA Today

Unhealthy diets and limited physical activity are leading causes of obesity in children, and now new research adds to growing evidence that the chemical BPA found in food packaging may be partly to blame.

The study, published in the journal PLOS ONE, shows girls between ages 9 and 12 with high BPA levels had double the risk of being obese than girls with low BPA levels, validating previous animal and human studies, said Kimberly Gray, a health scientist at the National Institute of Environmental Health Sciences.

.......

The study by Kaiser Permanente draws on urine samples of 1,326 male and female children from fourth through 12th grades at three Shanghai schools. Researchers took into account common obesity risk factors, including diet, mental health, amount of physical activity, and family history.

Girls between ages 9 and 12 with high levels of BPA — 2 micrograms per liter or more — were two times more likely to be obese than girls with lower levels of BPA in the same age group. Girls with very high levels of BPA — more than 10 micrograms per liter — were five times more likely to be obese, the study shows.

Read more: http://www.usatoday.com/story/news/nation/2013/06/12/bpa-obesity-puberty-girls/2413101/

[hlthe2b]

1. Fat stores BPA... Are they more obese because of BPA or because they have more Fat, is there more

stored BPA...

This one is not clear, but I've sought not to use products containing BPA for several years. Most canned foods remain a problem, unfortunately.

[siligut]

2. BPA mimics estrogenic activity

Extra estrogen can cause increased fat storage.

[hlthe2b]

6. Yes, but that does not answer the key question: which came first, "chicken or egg"

as defined above...

[siligut]

8. More estrogen, depending upon the person, can increase appetite and fat storage

So it is both really, but estrogen receptors in the brain are the culprits and some people are more susceptible than others. Worse than fat though is the estrogen related cancers and the feminizing of males.

[hlthe2b]

9. You miss the point... The findings of this study can not distinguish between

whether there is really more fat as a result of BPA or if because there is more fat there is more BPA.

The estrogenic effects are a theory as to how BPA could be infuencing, but this study proves nothing.

[siligut]

10. Do we have to only use the article for information in LBN?

I was speaking in general, now I understand the miscommunication. Yes, the fat storage of steroids is a given.

[hlthe2b]

11. To show causality, one needs biologic plausibility (the estrogenic theory from in vitro

or animal studies), validated statistical correlation from repeated studies, and temporality (showing "cause" precedes outcome)... It is the latter that is wanting in these BPA studies. Either someone will need to conduct a well designed longitudinal study (harder now that BPA is gradually being removed from commercial products), or a combination of several really well designed retrospective studies with longitudinal animal studies.

I think someone will eventually prove, but we haven't yet.

[arcane1]

3. And, of course, eating food that comes in "packaging" vs eating natural food

It warrants more study regardless.

[antigone382]

13. My thought is that since the study controls for other contributors to obesity

such as diet, family history, and physical activity levels, it is somewhat more likely that the BPA may be the causal factor. That doesn't rule out other possibilities entirely, but few such studies really can fully exclude all other possibilities. It is merely one more study that shows a correlation, which must be put into the context of existing and future literature on the subject.

[hlthe2b]

14. establishing temporality (what came first) is a mandatory requirement for establishing causality

So, no.

[antigone382]

15. I understand that, but there is a difference between "suggesting" and "establishing."

I understand the scientific method as it is intrinsic to my field, so I really don't need it explained to me, thank you.

The study builds on existing evidence that there *is" a link between obesity and BPA levels, whatever the causal mechanism. The article acknowledges the limits of the study in a way that science writing rarely does, and there are quotes from experts in the field about the need for the kind of longitudinal study you suggest elsewhere in this thread. Nevertheless, this is a case where I would err on the side of the precautionary principle; knowing there is a correlation between a chemical's levels in the body and a negative physical health outcome, even without the certainty that the chemical is the *cause* of that outcome, I think it is wise to reduce--and if possible eliminate--exposure to that chemical, until such time as it is proven to be harmless. What I dislike are statements such as this one from the article:

"Attempts to link our national obesity problem to minute exposures to chemicals found in common, everyday products are a distraction from the real efforts underway to address this important national health issue," the American Chemistry Council, a major trade association, wrote in a statement.

There is every reason to determine whether and to what extent there exist links between physical health outcomes and our "minute exposures to chemicals found in common, everyday products." I appreciate pointing out the limits of any one study, and calls for the kind of well-designed study that would yield a slam dunk. But I also accept the findings of less expensive but still professionally designed studies that build on a growing body of work.

[hlthe2b]

16. It is a valid correlation study, but some have tried to make more of it...

Even with the body of literature, the causality between BPA and obesity has not been established... I will not be surprised if it is in the future, but this study does not.

And, no matter how well one controls for confounders as you suggest, the temporality issue remains.

On edit, no where have I stated anything that suggest I disagree with the appropriateness of reducing exposure to BPA... If you re-read my earlier post(s), quite the opposite. The issue is can we state what some have tried to put forth as a conclusion, i.e., that this study "proves" that BPA is a cause of obesity.

[DeSwiss]

4. K&R

http://vimeo.com/34176018

[bananas]

5. "There's this dogma that weight is about calories simply going in and out.

"There's this dogma that weight is about calories simply going in and out. This research suggests that's simply not the case," said Bruce Blumberg, a professor of pharmaceutical sciences at the University of California, Irvine. Blumberg was not involved in the study.

[alp227]

7. BPA also used to exist in baby bottles too i think.

And I'm glad the FDA banned BPA from baby bottles. If BPA screws up older childrens' metabolisms I can't imagine for babies.

[dipsydoodle]

12. I'm inclined to agree with the link.

Back in the fifties when most , maybe all , things were still in glass bottles or jars I have no recollection of seeing any "fat girls" at all.