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Scleroderma is not common. It afflicts about 300,000 Americans, but only about 49,000 have the systemic form of the disease. The cause of scleroderma has not been determined, and there are few specific risk factors. The incidence tends to be higher in certain groups, however.
Age. Systemic scleroderma usually develops between the ages of 35 and 55. Localized scleroderma is more common in children than adults, but is extremely rare even in the young age group. It occurs in between 0.2 and 0.4 per 100,000 people. Systemic scleroderma is even more rare in children.
Gender. The incidence of scleroderma is three to eight times higher in women than in men. This may reflect a different cause of the disease in these two genders. (It should be noted that pregnancy itself is not a risk factor for scleroderma and that women in general are more susceptible to autoimmune diseases than men.)
Family History. A family history is the strongest risk factor for scleroderma, but even among family members, the risk is very low (less than 1%).
Genetics. Genetic factors appear to play a role in triggering the disease, but most cases are unlikely to be inherited. Preliminary research suggests that patients with certain gene variations may be more susceptible to scleroderma than those who do not carry these variations.
Ethnicity. Limited data on risk by ethnic group in the United States suggests that the risk from highest to lowest is the following: Choctaw Native Americans (highest), African-Americans, Hispanics, Caucasians, Japanese Americans.
African-Americans have a higher rate of diffuse scleroderma, lung involvement, and a worse prognosis than Caucasians. Other studies also found lower survival rates among Japanese Americans.
Genetic factors affect population groups differently. Studies are finding that ethnic groups differ in the number of specific scleroderma-related antibodies they produce. Caucasians, for instance, have a higher rate of anti-centromere antibodies, which are associated with limited disease, while African-American patients have higher rates of autoantibodies and genetic factors that are associated with a more severe condition. The condition is also more severe in Native Americans.
Review Date: 01/04/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.