Hygiene hypothesis gets a shot in the arm.

hy-poth-e-sis : \hī-ˈpä-thə-səs\ (noun)

1. A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

If you follow research for Crohn’s disease or other auto-immune problems you eventually run into the idea of the  ”hygiene hypothesis”. The basic concept is that when people are exposed to dirt, germs, allergens, microbes, and other unhygienic conditions early in their lives they are less likely to develop auto-immune problems like asthma, allergies and even Crohn’s disease. I believe the correlation between the two has been accepted as fact, but until the study linked below, I’ve not seen evidence of possible causation.

Researchers at Brigham and Women’s Hospital (BWH) have conducted a study that provides evidence supporting the hygiene hypothesis, as well as a potential mechanism by which it might occur.

Here’s your link.