Several recent studies have suggested that the incidence of systemic lupus erythematosus (SLE) is increasing. The female to male ratio varies from 4.3 to 13.6. SLE is more common in African-Americans, African-Caribbeans, and Asians, than in Caucasians. The age at diagnosis is younger in African-Americans than in Caucasians. Improvement in survival levelled off in the 1980s; 20-year survival is only 53-61%.