In medicine, the hygiene hypothesis states that an excessively hygienic environment in early childhood may predispose some people towards asthma, allergies, and other autoimmune diseases.

David P. Strachan first proposed the idea in an article published in the British Medical Journal (now BMJ), in 1989. It is hypothesized that in the absence of sufficient natural antigenic challenges, the child's developing immune system may start to target the body's own tissues instead, resulting in autoimmune disease in later life. The hypothesis attempts to account for the inverse relationship observed between infections early in life and the development of atopy. It is thought that numerous infections early in life favor the development of T helper type 1 cytokines (Th1), whereas fewer infections promote T helper type 2 (Th2) cytokines, and atopy.

The Collaborative on Health and the Environment references studies that question the consistency of scientific evidence and the higher risk in children in urban areas and developing counties.

Recently, researchers at the Duke University medical center have conducted research that supports this hypothesis. ^*

External links

• Bacterial Infections Alter Allergic Response: Findings Support Hygiene Hypothesis Abstract Text

• The Collaborative on Health and the Environment: Asthma: What we know (see also article by Dr. Gina Solomon in the peer-reviewed analysis section)

• Wild vs. lab rodent comparison supports hygiene hypothesis"

Hygiene