Tobacco smoking poses significant threats to public health and kills more than 6 million people annually worldwide, making it one of the three leading components of the global disease burden in 2010.1 Despite 50 years of prevention efforts, smoking remains the greatest cause of preventable diseases and deaths; each year, nearly 500,000 Americans die prematurely from smoking, and more than 16 million Americans suffer from a disease caused by smoking. Even though today's users smoke fewer cigarettes than those 50 years ago, they are at higher risk of developing adenocarcinoma, possibly because of ventilated filters and greater amounts of tobacco-specific nitrosamines in cigarettes.2
