Nice that the Duke folks say the same thing as has been said here many times:
"SMOKING DANGERS: Strangely enough, nicotine is not what makes smoking so harmful. The real villain is the cigarette itself, which pumps more than 4,000 chemicals into the body, about 200 of which are poisonous. The damage done to the heart and lungs is primarily due to tars, carcinogens (cancer-causing chemicals), and carbon monoxide in smoke. Compared to a cigarette's other hazards, nicotine is fairly safe......."