About 80% of people who have systemic sclerosis are women. It is estimated that about 300,000- 700,000 Americans have scleroderma. About 2.5 million persons worldwide have scleroderma. Scleroderma occurs most frequently between the ages of 25 and 55 years, although it can begin at nearly any age. About one-third of those with scleroderma have the systemic form of scleroderma.