Table 1. Demographic and clinical characteristics of IPF patients and healthy control subjects.

Characteristics	IPF (n=83)	Healthy control (n=38)	P value
Men/women	65/18	25/13	0.143
Age, years (mean ± SD)	66.90±0.85	68.26±1.01	0.345
Smoking status
Never-smoker	20	10	0.793
Former smoker	58	25	0.653
Current smoker	5	3	0.701
Serum KL-6 (U/mL)	865.3±54.65	1,686±49.80	<0.0001

IPF, idiopathic pulmonary fibrosis; KL-6, Krebs von den Lungen 6.