Research carried out by Dr Rui Jiang of Columbia university medical centre in New York showed that the 'odds ratio' for developing COPD among people who ate cured meat products 14 times or more per month was 1.93, as compared with those who did not consume cured meats. An odds ratio greater than one implies that the event is more likely to occur within that group.
Jiang said: "Cured meats, such as bacon, sausage, luncheon meats and cured hams, are high in nitrites, which are added to meat products as a preservative, an anti-microbial agent, and a colour fixative. Nitrates generate reactive nitrogen species that may cause damage to the lungs, producing structural changes resembling emphysema."
Previous rodent studies have suggested that inhalation of nitrogen dioxide may contribute to emphysema, but no other human studies to date have examined the relationship between consumption of cured meats and COPD, which is the fourth leading cause of death in the U.S.
Jiang looked at the tendency of those who eat a lot of cured meat to have unhealthy lifestyles generally: "Individuals who consumed cured meats frequently were more likely to be male, of lower socioeconomic status, to be tobacco users, and were less likely to report physician-diagnosed asthma than individuals who never consumed cured meats," he said.
"Those who consumed cured meats more frequently had lower intakes of vitamin C, beta-carotene, fish, fruits, vegetables, and vitamin or mineral supplements. They also had higher intakes of vitamin E and total energy."
But he said results had been adjusted to take lifestyle factors into consideration: "Adjustment for these factors in our analyses did not appreciably change our findings, suggesting that the observed association between cured meats and lung function was unlikely to be explained by potential dietary confounding factors reported in previous studies," said Jiang.