People who eat the most cured meats are more likely to have chronic obstructive pulmonary disease than those say they don't eat them, researchers from Columbia Medical School said.

Dr. Rui Jiang theorized that because foods such as bacon, sausage, luncheon meats and hams are high in nitrites -- a preservative and colorizer -- they cause damage to the lungs that resembles emphysema.

In the study, less than 10 percent of people who said they never eat cured meats had COPD. Those who ate it the most had a 20 percent chance of being diagnosed with COPD.

COPD is the fourth leading cause of death in the U.S., a news release said. Eleven million adults are thought to have COPD, which results from bronchitis and emphysema.

The researchers looked at data on more than 7,300 people over age 45 surveyed from 1988 to 1994. They also found that people who ate the processed meats more often were more likely to be male, have lower economic status and to use tobacco. They generally had lower intakes of vitamin C, fish and fruits and vegetables. But researchers said the difference based on meat persisted even when they adjusted statistically for those factors.

However, further research would be needed to definitively establish the link to cured meats as a risk factor for COPD. The results are considered very unlikely to be due to chance.

The study results appear in the second issue for April 2007 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.