From the New York Times last week:
The international study, led by Dr. Xiaobin Wang and Dr. Jacqueline A. Pongracic of Children’s Memorial Hospital here, is searching for causes of food allergy by looking at hundreds of families in Boston, Chicago and Anhui Province in China.
In China, for example, skin-prick testing found that large percentages of one rural population were sensitive to shellfish (16.7 percent) and peanuts (12.3 percent). Yet actual food allergies in that population, as diagnosed by physicians, were all but unheard of: less than 1 percent.
“We found something unexpected,” said Dr. Wang, director of the Smith Child Health Research Program at Children’s Memorial. “The apparent dissociation between high allergic sensitization and low allergic disease in this Chinese population is not seen in our two U.S. study populations.
And they are trying to uncover the reasons for the difference. We shall wait and see with great interest.