Sausage, along with its cured cousins, including bacon and luncheon meats, have been associated with an increased risk of developing chronic obstructive pulmonary disease (COPD). The culprit for this increased risk is the high level of nitrites in cured meats, according to a study published to appear in the second issue for April 2007 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society. Nitrites are added to meat as a preservative, antimicrobial agent and color fixative. Lead author of the study, Dr. Rui Jiang of Columbia University Medical Center in New York, pointed to earlier studies that show nitrites can cause structural damage in the lungs, resembling emphysema. Nitrites form reactive nitrogen proteins that can damage the lungs, causing structural damage. Dr. Clay Marsh, professor of internal medicine and director of the division of pulmonary, allergy, critical care and sleep medicine at Ohio State University Medical Center, emphasized that even with these findings, it is important to recognize that smoking is still the primary cause of this disease. "The most important consideration is get people to not smoke, or stop smoking, and deliver the message to kids and younger adults to prevent the disease by not smoking," Marsh said, "but this is an interesting study, it is provocative to look at the role of nutritional substrates in disease."