Evidence of 'economic' theory of health?

[c1ue]

In immunology - there is a theory that the antigens in each person's body are apportioned according to exposure; too little variety of exposure results in too many antigens focusing on too few different foreign objects thus resulting in auto-immunity disorders like allergies.

Another branch of immunology believes that the human body incorporates outside 'beneficial' types of bacteria as part of its normal defenses - and that broad spectrum antibiotics affect this balance.

http://www.sfgate.com/cgi-bin/blogs/...entry_id=77917

You've heard of too much of a good thing, right? Well, humans may just have too much cleanliness for our own good.

Triclosan, the ingredient in most antibacterial soaps and gels, was first developed for use in medical settings. Its benefits there are undeniable. But everyday use of triclosan exposes users to unnecessary chemicals and fails to keep them any healthier than non-users.

Scratch that: It actually makes users sicker. A new study conducted by researchers at the University of Michigan School of Public Health found that, among those 18 and under, higher levels of triclosan in urine correlated with higher rates of allergies. The researchers drew from data produced for the the 2003-2006 National Health and Nutrition Examination Survey.

You see, triclosan doesn't just target the bacteria that make us sick; it targets all bacteria — and some bacteria are beneficial to humans.

"The triclosan findings in the younger age groups may support the 'hygiene hypothesis,' which maintains living in very clean and hygienic environments may impact our exposure to micro-organisms that are beneficial for development of the immune system," said Allison Aiello, associate professor and the principal investigator.

The findings, the authors also noted, document a strong correlation, but do not prove causality. The study appears in Environmental Health Perspectives.

[don]

Re: Evidence of 'economic' theory of health?

Wonder if this has an expiration date. Does this apply to seniors- say 75 and up- or is it better for them to observe obsessive cleaning, a phenomenon I observed on a trip to Florida to visit my wife's parents. Restaurants that catered to a senior clientele were awash with this behavior.

[c1ue]

Re: Evidence of 'economic' theory of health?

That's a good question - as you get older both your immune systems and your general level of body function level off.

Among many questions if the 'economic' theory of immunology is correct:

What are the 'economic' response levels for different age groups?

What impact do 'beneficial' bacteria play for the older demographic? Much like a remora on a shark has little impact on a healthy young shark, the same remora might have a negative impact on an older shark which has difficulty hunting.

What is the impact of widespread vs. narrowly focused immune responses?

How quickly does the body learn/de-emphasize specific antigens?

These and more are important because of wide ranging societal recommendations such as what you noted. Another example would be flu shots.

[ThePythonicCow]

Re: Evidence of 'economic' theory of health?

Statistical correlation studies are the bane of modern medicine. Not only do they not prove causality, as you note, but they misrepresent what is meant by a strong correlation.

The lay understanding of a "strong correlation" is that it means that there is a high degree of probability that you can correctly guess one factor, given the other. For example, there is a strong correlation between number of feet and species of animal. Most horses have four legs, most humans two.

The statistical understanding of a "strong correlation" is that there is a high degree of probability that there is a non-random (albeit perhaps minute) difference. For example, I would wager that there is a "strong correlation" between number of fingers and gender, for humans. The average number of fingers on a male hand is likely slightly less than on a female hand, because males more often engage in the sorts of activities that cause loss of fingers. To pick numbers out of the air, if my wager is correct, there might be an average of 4.9998 fingers on male hands, and an average of 4.9999 fingers on female hands. The difference is very, very minute (unless I suppose you're one of those who has lost a finger), but (if my wager holds) statistically very very strong across any sufficiently large population.

Given any sufficiently large population, and given enough various measurements of that population, the probability that one can find yet another, not yet published, pair of measurements demonstrating a "strong correlation" approaches certainty.

In this case, they couldn't even meet the "non-published" criteria. See The Ubiquitous Triclosan A common antibacterial agent exposed, by Aviva Glaser, published in Vol. 24, No. 3, 2004 of "Pesticides and You". Search google to find the pdf-to-text form; the only original pdf link that I could find no longer works.

Quoting from Glaser's 2004 paper:

Allergy Link.
Another potential problem with overuse of triclosan (and other antibacterials) is their link to allergies. The “hygiene hypothesis,” theorizes that there is a correlation between too much hygiene and increased allergies and asthma. This hypothesis is based on studies that have found an increase in the frequency of allergies, asthma, and eczema in persons who have been raised in more sterile and hygienic environments. Through over-cleaning ourselves, the theory states, the body’s immune system is not challenged, and thus prevent it is prevented from developing and maturing. In one study, children who grew up on farms had fewer allergies than did their counterparts who did not live on farms. In another study, researchers found that respiratory allergies were less frequent in people who were heavily exposed to microbes, leading the researchers to conclude that, “Hygiene and a westernised, semisterile diet may facilitate atopy by influencing the overall pattern of commensals and pathogens…thus contributing to the epidemic of allergic asthma and rhinitis in developed countries.”

Two possible causes for this correlation come to my mind offhand:

1. Perhaps triclosan suppresses gut bacteria, and perhaps that in turn harms the immune system (by letting too many toxins into the blood system, perhaps.)
2. Perhaps there is a positive correlation between use of triclosan in homes with children, and use of sun screens in those homes, and perhaps (likely, in my view) increased use of sun screens causes lower Vitamin D levels, in turn harming the immune system.

However without a key number, necessary to evaluate whether the correlation is "strong" in the first, lay sense above, rather than in just the second, statistical sense, we cannot even tell whether this is a correlation of practical interest. In other words, unless we know that there is a substantial difference, rather than just a statistically reliable, but only slight difference (an almost complete overlap of the two statistically defined groups), such correlations are more often dangerously misleading than usefully suggestive.

The key number, which as usual I don't see here, is how much separation there is between the two statistical groups, say in terms of standard deviations of the metric in question.

Do we have this:

or do we have this:

[ThePythonicCow]

Re: Evidence of 'economic' theory of health?

P.S. -- Nothing I posted above should be construed as a defense of triclosan. I have none of the stuff in my house so far as I know, and I intend to keep it that way.

[c1ue]

Re: Evidence of 'economic' theory of health?

Statistical correlation studies are the bane of modern medicine. Not only do they not prove causality, as you note, but they misrepresent what is meant by a strong correlation.

The lay understanding of a "strong correlation" is that it means that there is a high degree of probability that you can correctly guess one factor, given the other. For example, there is a strong correlation between number of feet and species of animal. Most horses have four legs, most humans two.

This is a very good point.

The study in question doesn't list the differences, but I have seen studies where the numbers of people who suffer allergies vary significantly (more than 2 to 1) between those who live in urban settings vs. those who live in rural settings.

Similar numbers exist for historical rates of auto-immune disorders vs. today.

Of course this doesn't per se validate the 'economic' theory of immunology - the cause might well be something additive as opposed to negative such as modern chemicals.

The sad part of all this is that due to over-focus of commercial interests, the purely scientific portion of basic research is being sadly neglected with very likely important knowledge thus being missed.

The bacterial component to ulcers is an excellent example.

[flintlock]

Re: Evidence of 'economic' theory of health?

I'd make a good lab rat on this subject. I am an identical twin. Raised together, ate the same, worked the same job, same college even. I have auto-immune disease, he doesn't. Go figure.

[ThePythonicCow]

Re: Evidence of 'economic' theory of health?

I have auto-immune disease, he doesn't. Go figure.

What do you suspect caused this difference?

[flintlock]

Re: Evidence of 'economic' theory of health?

What do you suspect caused this difference?

My only guess,( and its just a guess) is that I was exposed to tons of cigarette smoke while working my way through college with a bunch of redneck electricians. Why? Because that's when the problems started, my brother never was exposed to any cig smoke, and I was completely healthy before hand.( Ate well, ran 4 miles day, worked out) I'd get to the shop at 6am, sitting among the chain smokers for 30 minutes or so, then hop in a closed van for the hour ride to the job. Same thing on the way home. To this day I can't be around even a bit of smoke. Chokes me up immediately. About the only thing I know I'm allergic to. Feels like being gassed with CS. My brother only recently ( 25 years later) started having some health issues. But I'm not sure if his problems are related to mine. I sometimes wonder if the tobacco smoke didn't act as some sort of trigger.

The really bad thing out of all of this is that in my desperation to get help I allowed a "surgeon" to operate on me leaving me with chronic pain the last 23+ years. Much worse than any of the original symptoms. I know all too well the pitfalls of "modern medicine".

[ThePythonicCow]

Re: Evidence of 'economic' theory of health?

My only guess,( and its just a guess) is that I was exposed to tons of cigarette smoke ...

That sounds plausible ...

The really bad thing out of all of this is that in my desperation to get help I allowed a "surgeon" to operate on me leaving me with chronic pain ...

... and that sucks .

[c1ue]

Re: Evidence of 'economic' theory of health?

To this day I can't be around even a bit of smoke. Chokes me up immediately

Well, one way to test out the 'economic theory' on yourself is to increase your exposure to new substances.

Some ways:

Add 5 or 6 completely different types of food into your diet - odd stuff like rhubarb, rabbit, wild venison, brussels sprouts, etc - assuming you've not regularly eaten these already
Get a type of pet your never had before (dog, cat, turtle, whatever).
If you go camping, go places where you've never been before in the spring (pollen exposure)
Put in a completely new type of upholstery in your car/office/home

I think you get the idea - if the theory is true, then exposure to many types of new potentially antigen sensitizing new substances will reduce the numbers and thus effect of existing sensitivities.

It certainly worked for me with alcohol. I used to not be able to drink anything but scotch and the more decent wines - I'd get a horrible itch all over.

Not a problem anymore...

[flintlock]

Re: Evidence of 'economic' theory of health?

Yes, maybe I'll start with alcohol........