Table 1.

Sex ratios for connective tissue autoimmune diseases

Disease	Female:male ratio	Peak age at onset	Reference
Rheumatoid arthritis	2:1 to 3:1	Forties	[83]
Systemic lupus erythematosus	9:1	Late teens to early forties	[6]
Systemic sclerosis	3:1	Fortiesa	[4]

^aKnown to vary due to ethnicity.