Table 1.

Interstitial lung diseases associated with connective tissue diseases

Rheumatic disease	Frequency of ILD (%)	Comment
Systemic sclerosis	45 (clinically significant)	More common in diffuse disease; topoisomerase-1 antibodies
Rheumatoid arthritis	20 to 30	Increased risk with cigarette smoking
Polymyositis/dermatomyositis	20 to 50a	More common with anti-synthetase antibodies
Sjögren's syndrome	Up to 25	-
Systemic lupus erythematosus	2 to 8	Usually in patients with multisystem disease
Mixed connective tissue disease	20 to 60	-

ILD, interstitial lung disease. ^aFrequency may be higher based on recent studies.