U.S. surgeon general says e cigarettes are health threat to youth Mayo Clinic News Network E cigarettes have public health benefits: Royal College of Physicians The debate over e cigarettes demands stronger evidence of their value New E Cig Trends from the Shenzhen E Cigarette Expo Tobacco Asia E CIGARETTE E cigarette health scare: Danger chemicals in liquid nicotine could cause 'popcorn lung', scientists warn The Mirror