- Overuse of antibiotics and over-hygiene has led to dramatic increase of allergic disease. The old hypothesis for this is that TH2, which is responsible for allergy, is not counterbalanced by TH1 that is stimulated by bacterial and viral infection. A new hypothesis is that reduced infection weakens the induction of a robust anti-inflammatory regulatory network by persistent immune challenge (Yazdanbakhsh, et al., 2002).
- The number of adults with diabetes in the United States increased by 49% between 1991 and 2000. Type II diabetes accounts for practically all of that increase. Some 16 million to 17 million people now have the condition, and an equal number are thought to be "prediabetic," having early symptoms but not yet the full-fledged version. Even children are no longer immune to diabetes 2, which until recently rarely affected people before middle age. Obesity is linked to Type II diatetes. Fat cells release a variety of hormonelike substances. (Marx, 2002).
- Cardiovascular diseases and major cancers differ 5- to 100-fold among various populations and that when groups migrate from low- to high-risk countries, their disease rates almost always change to those of the new environment (Armstrong and Doll, 1975, Kato et al., 1973). Integration of new genetic information into epidemiologic studies can help clarify causal relations between both life-style and genetic factors and risks of disease (Willett, 2002).
- The immune system is more concerned with entities that do damage than with those that are foreign (Matzinger, 2002).
References:
B Armstrong and R Doll (1975) Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices. Int. J. Cancer 15(4):617-31
H Kato et al. (1973)Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California. Am. J. Epidemiol. 97(6):372-85
J Marx (2002) Unraveling the Causes of Diabetes. Science 296: 686-689
P Matzinger (2002) The Danger Model: A Renewed Sense of Self Science 296: 301-305
WC Willett (2002) Balancing Life-Style and Genomics Research for Disease Prevention Science 296: 695-698
M Yazdanbakhsh et al. (2002) Allergy, Parasites, and the Hygiene Hypothesis
Science 296: 490-494.
