Proximity to Major Roadways is a Risk Factor for Airway Hyper‐Responsiveness in Adults

BACKGROUND: Proximity to major roads is reported to be associated with asthma and airway hyper-responsiveness in children. Similar studies using objective measurements in adults are not available in Canada. OBJECTIVE: To test the hypothesis that adult asthmatic patients who live close to major roads and highways in an urban environment are at a risk of moderate to severe airway hyper-responsiveness.