Being Too Clean Can Make People Sick

An anonymous reader writes "Young people who are overexposed to antibacterial soaps containing triclosan may suffer more allergies, and exposure to higher levels of Bisphenol A among adults may negatively influence the immune system, a new University of Michigan School of Public Health study suggests (abstract, full paper [PDF]). Triclosan is a chemical compound widely used in products such as antibacterial soaps, toothpaste, pens, diaper bags and medical devices. Bisphenol A is found in many plastics and, for example, as a protective lining in food cans. Both of these chemicals are in a class of environmental toxicants called endocrine-disrupting compounds, which are believed to negatively impact human health by mimicking or affecting hormones."

Comments

Yawn

[Kosi]

It's not new that our immune system has to be trained to work well. And only some kind of idiot doesn't make the link that keeping the kids away from every source of infection must result in an inferior immune system. Where's the news here?

Re:Anti-bacterial soap will kill you all.

[Beardo the Bearded]

My kids will turn on the taps, wait, and then turn the taps off just to avoid washing their hands. I was asking why the towel wasn't damp and they started rinsing their hands. Pests.

I stopped caring about germs. I bike to work, I exercise at the Y (26 minutes ago, excellent!), I have one kid in school and one in daycare, I SCUBA dive in the ocean (we discharge screened sewage here), and I eat at a pub about once a week on average. (the chefs there don't exactly use antibacterial soaps...) I've had someone puke in my mouth. (My daughter; she was very young and the game was very high.) Normal germs don't stand a chance in my body.

I licked my keyboard while I was posting this. I'm not afraid of germs.

Re:I've suspected this for years.

[ColdWetDog]

Except instead of your "hey wouldn't it be totally ironic if anti-bacterial soap made people SICKER!!??" observation, they have identified Triclosan and Bisphenol A as an endocrine disruptor with the specific function of inhibiting the immune system not by protecting it from exposure or selectively breeding resistant germs (the two popular "well duh" observations here) but by actually inhibiting the effectiveness of the immune system. Knowing this, as opposed to say "knowing that for sure, antibacterial soaps are totally bad because they don't let your body *learn* about bad germs!!!" is what leads to advances in medicine and pathogen control.

I'm not a doctor but I appreciate what they do.

Let's not get hasty here. They took some data previously collected:

Methods: Using data from the 2003-2006 National Health and Nutrition Examination Survey, we compared urinary bisphenol A (BPA) and triclosan with serum cytomegalovirus antibody levels and diagnosis of allergies or hayfever in US adults and children age 6 years. We used multivariate ordinary least squares linear regression models to examine the association of BPA and triclosan with cytomegalovirus antibody titers, and multivariate logistic regression models to investigate the association of these chemicals with allergy/hayfever diagnosis. Statistical models were stratified by age (

Then ran a series of statistical tests to see if there were any correlations between the body burden of BPA and triclosan and putative proxies for immune function (CMV titer and hayfever diagnosis).

They "adjusted" for a bunch of variables and come out with a correlation between the markers and their effects. They then go on to state that the chemicals may depress immune function.

It may be true but this sort of analysis is prone to a host of problems - poor data collection, poor data analysis, over correlation by the statistical software and god knows what else by the statistical software (disclaimer - I've only read the abstract, I don't know exactly how they did it but unless they have a very good statistician looking over their shoulders, they open to making any one of a number of mistakes).

And of course, our favorite logical fallacy: Correlation implying Causation. Specifically, the charge that the endocrine disruption mechanism of BPA and Triclosan is the cause of the immune changes is not addressed at all. It's simply assumed.

Unfortunately, this is like the vast majority of the literature in these areas. Because good science is so hard to do, we gets lots of these little studies that may or may not mean much of anything. They're fine, it's the way we have to do things, but don't flush all of the soap down the toilet.