> Although nicotine's primary risk is addiction or dependence on tobacco products, researchers found that 83 percent of doctors strongly believed that nicotine directly contributed to heart disease. In comparison, 81 percent thought it contributed to chronic obstructive pulmonary disease (COPD). Pulmonologists, who focus on the respiratory system, were less likely than other specialties to misperceive nicotine as a direct contributor to COPD. Family doctors were more likely than oncologists to misunderstand nicotine as a cancer-causing substance