Lending more credence to the increasingly popular "hygiene hypothesis" of asthma and allergies is this report. To summarize:

• Study included 235,477 children 13 to 14 years old from 23 countries, including many European countries, the United States, Australia, New Zealand and Canada
• There was a significant correlation between the prevalence of asthma or wheezing and reported rates of tuberculosis
• An increase in the tuberculosis notification rate of 25 per 100,0000 was associated with an absolute decrease in the prevalence" of reported "wheeze ever" of 4.7%

These results, the researchers conclude, "are consistent with recent experimental evidence which suggests that exposure to Mycobacterium tuberculosis may reduce the risk of developing asthma."

Thorax 2000;55:449-453.