World athletics' governing body has suppressed a 2011 survey that reveals that up to a third of the world's top competitors admitted using banned performance-enhancing techniques, Britain's Sunday Times and German broadcaster ARD/WDR reported.
The authors of the study, which involved interviews with 1,800 athletes at the 2011 world championships in South Korea, were told to sign a confidentiality agreement a month after the information had been collected and analyzed, the newspaper said.
The revelations are the latest in a series of damaging blows for the sport in the countdown to the start of this year's world championships in Beijing on Aug. 22.