(Reuters) - Lance Armstrong has stepped down as chairman of the charity he founded, Livestrong, after U.S. anti-doping officials issued a scathing report detailing his use of performance-enhancing drugs for years as one of the world's premier cyclists, the foundation said on Wednesday.

Separately, one of his main corporate sponsors, Nike Inc. said it was ending its sponsorship of Armstrong.

(Reporting By Dan Burns; Editing by Jackie Frank)