Scleroderma epidemiology

Systemic sclerosis has an incidence of approximately 20 new cases/million adults each year in the United States, and a total prevalence that is estimated at 240 cases/million adults. These estimates seem to be higher in the United States than in the United Kingdom, Europe, or Japan. The highest occurrence has been reported among Choctaw Native Americans and African Americans, which suggests a genetic predisposition, the exact nature of which is unclear. Familial clustering of scleroderma, which affecting 1.6% of families, also supports a genetic component. Survival has improved over the past several decades, but remains substantially lower than expected.