HumanaVitality, LLC is sponsoring endurance sports and other types of events to promote its eponymous wellness loyalty program.The 14-month-old joint venture between Humana Inc. and South Africa-based Discovery Holdings, Ltd. kicked off the initiative with a tie to the April 27 Kentucky Derby Festival Marathon and miniMarathon. HumanaVitality will co-present the event in 2013.  The company also will present the Sept. 19-22 IdeaFestival in Louisville, Ky. and the Nov. 3 Louisville Sports Com...