Researchers caution that the subject remains complex.
But reports from disparate states and countries are prompting a fresh look at an intractable health problem. 17.3 million Americans suffer from the respiratory disease and 5,000 people die from it each year. Millions more nurse runny noses, swollen eyes and itchy skin from less serious allergies. Most research has focused on how to reduce a sufferer's exposure to household irritants such as dust mites and pet dander. But I think those conclusions are being re-evaluated.