Globally, estimates of prevalence vary from 31.0 to 658.6 affected people per million. Systemic sclerosis has a female:male ratio of 3:1 (8:1 in mid- to late childbearing years). Incidence is twice as high among African Americans. Full-blooded Choctaw Native Americans in Oklahoma have the highest prevalence in the world (469 per 100,000).
GloBAlly, estiMates of pREValence varY fRom 31.0 to 658.6 aFFected PeOplE PEr Million. sYstemIC scLerOsiS hAS a FemaLe:male RaTio oF 3:1 (8:1 In MID- To late childBeArINg yEARs). iNcIdencE is twicE as high amONg african aMericans. Full-bloOdED choctaw natIvE americaNs in Oklahoma have the HIgHeSt prEvaLenCe IN the worlD (469 per 100,000).