January 26, 2009 About one third of the male adult global population smokes, two thirds in Asia where tobacco advertising is largely still legal. Among teens aged 13 to 15, about one in five smokes worldwide. Smoking is the single largest preventable cause of disease and premature death. Smoking related-diseases currently kill one in 10 adults globally, and on current trends, one in six of ALL people two decades from now. New UK research has found that smokers are twice as likely to kick the habit if they use a support group rather than trying to give up alone.