Our study will enroll 644 randomly-selected Canadians who have been diagnosed with asthma by a physician within the previous five years. It will be determined what diagnostic tests were initially performed to make this diagnosis. Participants will undergo lung function testing over 6-8 weeks to determine their respiratory status and to confirm they have asthma. Participants may be followed up to one year depending on their test results.

Inclusion Criteria:

1. Patient must have a recent diagnosis of asthma by a physician. Diagnosis of asthma must have occurred within 5 years prior to entry into the study.
2. Patient must be at least 18 years old.

Exclusion Criteria:

1. Patients in whom methacholine challenge is contraindicated

   • Patients using chronic oral prednisone.
   • Patients with heart attack or stroke within three previous months, and those with known aortic or cerebral aneurysms.
   • Pregnant patients (unknown effect of methacholine on the fetus) and breastfeeding patients (unknown whether methacholine is excreted in breast milk).

2. Patients unable to provide informed consent.

3. Patients not able to perform spirometry and/or methacholine challenge testing.

4. Patients who have a greater than 10 pack-year smoking history (this will exclude patients with possible COPD).

5. Patients who currently have active pulmonary Tuberculosis

6. Patients who have had eye surgery in the past 3 months or who have a detached retina

7. Patients involved in another interventional asthma study

Canadians diagnosed with Asthma and 18 years of age and older.