Scleroderma epidemiology.

The overall incidence and prevalence rates for scleroderma in the United States appear to be stable over the past 2 decades. Age-specific incidence rates are higher in black women than in white women, and diffuse disease is more common in the black population. Risk factors for disease development include female gender and may include HLA-DQ type. Diffuse disease, older age at onset, and early internal organ involvement are risk factors for reduced survival. Genetic factors appear to play a permissive role, whereas as yet undefined environmental factors play a more direct role in disease causation.