Hey Maw, the Youngin's Getting Dirty Again..That's A Good Thing!

It has been said that the Internet is causing heavy search engines users to think less deeply. In fact, I just read the book The Shallows: What the Internet Is Doing to Our Brains, It's not as corny as the title might lead one to believe. It concerns itself with neuroplasticity. While this is, in and of itself factual, the good news is that out search engine transformed noodles can--thankfully--be switched back to modes of heavier lifting in very short order.

So, just what does this have to the topic at hand? Good question. The answer is that it really doesn't have a thing to do with dirty misbehaving rugrats. However, I do have a method. The Internet is a great big messy database of some useful, but mostly it seems, useless information. That said, the Internet allows hacks like me to tunnel tight into hard science journals. That, gentle reader is the reason for the tortuous route I've had you folliow to get to the heart of the matter.

Without further ado, this segment of "as my stomach turns" burrows right into The Journal Of Allergy and Clinical Immunology. Here's where those carpet roaming fresh humans come into play.

Yes, the link gives you access to the full journal paper. Is that so shallow? Nah. For those not inclined to read dry scholarly treatments, the paper can be summed in a few simple words.

Let your infants get some exposure to allergens and bacteria. In other words, let 'em get dirty! The payoff can be enormous. Heck, I'll even quote from the paper:

Methods

The Urban Environment and Childhood Asthma study examined a birth cohort at high risk for asthma (n = 560) in Baltimore, Boston, New York, and St Louis. Environmental assessments included allergen exposure and, in a nested case-control study of 104 children, the bacterial content of house dust collected in the first year of life. Associations were determined among environmental factors, aeroallergen sensitization, and recurrent wheezing at age 3 years.

Results

Cumulative allergen exposure over the first 3 years was associated with allergic sensitization, and sensitization at age 3 years was related to recurrent wheeze. In contrast, first-year exposure to cockroach, mouse, and cat allergens was negatively associated with recurrent wheeze (odds ratio, 0.60, 0.65, and 0.75, respectively; P ≤ .01). Differences in house dust bacterial content in the first year, especially reduced exposure to specific Firmicutes and Bacteriodetes, was associated with atopy* and atopic wheeze. Exposure to high levels of both allergens and this subset of bacteria in the first year of life was most common among children without atopy or wheeze.

Conclusions

In inner-city environments children with the highest exposure to specific allergens and bacteria during their first year were least likely to have recurrent wheeze and allergic sensitization. These findings suggest that concomitant exposure to high levels of certain allergens and bacteria in early life might be beneficial and suggest new preventive strategies for wheezing and allergic diseases.

I know what you're thinking.."Hey, this study only applies to urban cradle crawlers. I live in the sticks." Fear not uptight parent. One can certainly apply the data here to your rural papooose filler.

A really close look at the data is quite revealing. Essentially, the younger the child is during exposures, the healthier they are as they mature. At least to the age of three to four years. Exposure at three years or older gives the expected result of the child having more allergic reactions, and susceptibility to bacterially induced wheezing and atopy.* At first blush it seems that the study's authors were expecting a different outcome. Even upon further reflection this could indeed be the case. The inverse relationships between early exposures and later lack of symptoms is both a bit counterintuitive and refeshingly positive. Human endogenous immune responses continue to amaze and delight. Okay, maybe not you, but me.

* Atopy is the tendency to be "hyperallergic." Atopy has a strong genetic component. In this study, one can infer that the atopic reactions are wheezing and allergen related asthma.