Table 2. Clinical and demographic IPF variables categorized by D_LCO.

Variable	Characteristics	Mild IPF (N = 16)	Severe IPF (N = 15)	Controls (N = 27)
% Predicted DLCO		77.1±11.9	27.4±5.3	NR
Age	Mean±SD	67.4±6.0	66.8±13.7	60.1±14.1
Sex	Male/Female	11/5	11/4	11/17
Smoking Status	Current	0	0	0
	Former	7	10	14
	Never	8	5	13
	Not Reported	1	0	0

Abbreviations: Idiopathic Pulmonary Fibrosis (IPF); Not Reported (NR); Diffusing Capacity for Carbon Monoxide (D_LCO); Forced Vital Capacity (FVC).