Figure 2.

Asthma/COPD overlap in WTC-exposed firefighters who had a BD-PFT. The Venn diagram demonstrates abnormalities on BD-PFTs obtained via the WTC treatment program. Isolated-asthma was diagnosed in 202 individuals who had FEV₁ BD response of > 12% and 200 mL. Isolated-COPD was diagnosed in 215 individuals who had a post-BD FEV₁/FVC ratio < 0.70. Asthma/COPD overlap was diagnosed in 99 who had both an FEV₁ BD response > 12% and 200 mL, and an FEV₁/FVC ratio < 0.70. The remainder of the study population (n = 1,621) did not have a BD response or airflow limitation. See Figure 1 legend for expansion of abbreviations.