Montreal — A 10-year global study of positive doping tests by children and young teenagers showed most were tied to Russia, India and China, and in sports like weightlifting, athletics and cycling, the World Anti-Doping Agency said Wednesday. Diuretics, stimulants and anabolic steroids were the most commonly found substances in more than 1,500 positive tests involving more than 1,400 minors since 2012. The youngest athlete tested was 8 years old, and the youngest sanctioned in a doping case was a 12-year-old, WADA said in the Operation Refuge study. "Operation Refuge reports in heartbreaking detail the deep trauma and isolation child athletes experience following a positive test and a doping sanction," the chair of WADA's athlete council, Ryan Pini, said in a statement. It cited the testimony of a female minor "who…