Methods: A 3 year prospectie study inoling methacholine challenge tests and serially administered questionnaires was undertaken in 769 apprentices exposed to high molecular weight allergens.

• 方法:在为期3年的前瞻性研究中，对769名暴露于高分子量变应原的学徒工进行乙酰甲胆碱激发试验和系列的问卷调查。