Sausage gets a bad wrap. And the news is not getting better. Now 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.

This structural damage can result in partially blocked airways, resulting in COPD, which includes emphysema and chronic bronchitis.

COPD is the fourth leading cause of death in the U.S., with more than 12 million Americans diagnosed, and another estimated 12 million who have COPD and may not even know it, according to the National Institute of Health.

Cigarette smoking is the leading cause of COPD, but with a projection of rising to the third leading cause of death worldwide by 2020, researchers are looking for other causes.

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."

The study did note that people who consumed cured meats are more likely to be male tobacco users, with lower intakes of fish, fruits, vegetables and vitamin supplements.

This study of 7,352 participants over the age of 45 found that those who ate more than 14 servings of cured meats per month had a significant lower lung function test and increased odds of COPD, as compared with those that did not eat cured meats.

Each additional serving per month in cured-meat consumption was associated with a 2 percent increased risk for COPD, according to the findings.

Researchers did adjust for dietary factors, as well as smoking, age, sex, ethnicity, income and body mass index, and still found the findings were appreciable after that adjustment.

"Right now we cannot say that cured meats cause COPD," Jiang said. However, these findings do open up an avenue for further research into dietary considerations and COPD.

"There are a number of studies looking at inhaled nitrogen radicals on lung function," Marsh said. "One thing that is interesting about this study is that these are not inhaled substances, these are ingested."

Ingested nitrites do not come in direct contact with the lung, so Marsh suggested "the dietary materials that don't directly interface with the lung still might have an adverse manifestation on lung function."

For people who are already predisposed genetically to lung disease, this information could be used to inform those patients.

For instance, individuals with a deficiency of alpha-1 antitrypsin, a protein that protects the lungs, could be instructed to avoid cured meats on a regular basis.

"This would be something that would be easy to recommend to people with a history of lung disease, that this is a very reasonable adjustment to make," Marsh said. "With a risk benefit analysis, there is no benefit to eating cured meats, while the positives of stopping eating them could be something."