RESULTS: A total of 15,837 PFTs were completed. 14,628 sets of PFTs were included in the final analysis. This included 6,785 PFTs on current or former smokers (average 18.7 pack-years) and 7,843 PFTs on lifelong non-smokers. The ages ranged from 17-74 years (mean 40.2). 98% were male, and 96% were Caucasian. 14,415 sets of PFTs contained spirometry, while 9,353 had lung volume and 8,970 had diffusion capacity measurements.