Systemic scleroderma may occur at any age, but the symptoms most frequently begin in mid-life (25-45). The diffuse and limited forms of scleroderma are very rare in children. The disease is about 4 times more common in women than men for diffuse variants of scleroderma with a slightly higher female-male ration in the limited variants. There is some evidence that black women have a significantly greater risk than white women. In addition, diffuse scleroderma appears to occur more frequently among black women and starts at an earlier age. Native Americans of the Choctaw tribe have especially high rates of scleroderma.
There seems to be a relatively weak genetic link with scleroderma. Close order relatives of an affected individual are more likely to have some type of autoimmune condition but this is more likely to be a different disease, such as rheumatoid arthritis, Hashimoto’s (autoimmune hypothyroidism), Graves (autoimmune hyperthyroidism), or lupus. Also, close order relatives of affected patients may have elevated ANA levels as compared to the normal population, but without any symptoms of any autoimmune disease.