Study Links Cured Meats to Lung Disease
But more research is needed to prove the association, experts say
MONDAY, April 16, 2007 (HealthDay News) -- As if you needed another reason to improve your eating habits, researchers have demonstrated a possible link between a diet rich in cured meats -- such as hot dogs, bacon and deli meats -- and chronic obstructive pulmonary disease.
Dr. Rui Jiang, an associate research scientist at Columbia University Medical Center in New York City, led the study that examined the diet and lung function of 7,352 people with an average age of 64.5 years.
Using data compiled as part of the Third National Health and Nutrition Examination Survey, the study authors found a statistical association between people who ate 14 or more servings monthly of cured meats and the incidence of chronic obstructive pulmonary disease (COPD). This held true even after the researchers factored in such variables as age, smoking, and the amount of fruits and vegetables in the subjects' diets.
"People who eat 14 or more servings of cured meat per month have about an 80 percent increased odds of COPD versus people who don't eat cured meat at all," Jiang said.
And, the more cured meats a person eats a month, on average, the higher the risk of COPD, the study said.
The findings were published in the April issue of the American Journal of Respiratory and Critical Care Medicine.
According to the American Lung Association, COPD is an umbrella term for emphysema and chronic bronchitis, and the fourth leading cause of death in the United States. The single greatest risk factor for the disease is smoking.
Yet, the association between COPD and cured meats doesn't come entirely out of left field. Cured meats are rich in nitrites, which have, in animal studies, been linked to lung damage. No epidemiologic study had ever been done to test the possible association between cured meats and lung disease in humans, however, Jiang said.
"There is a plausible background to it," said Dr. Neil Schachter, professor of pulmonary medicine at the Mount Sinai School of Medicine in New York City. "They (the study authors) are not the first to say that diet may impact lung disease, and certainly there have been many hypotheses about chemicals and oxidative species that may enhance the development of chronic lung disease."
This study does not, however, prove cured meats actually cause COPD, Schachter said. "Associations don't mean causality," he said. "That's the bottom line of an epidemiologic study. Because even though they control for many variables, they cannot control for everything."
Dr. Norman Edelman, chief medical officer of the American Lung Association, who called the findings "interesting," echoed that sentiment. "Like any correlational cross-sectional study, there's always the possibility there's some other confounding variable they haven't considered."
Food brand choice, nutritional content and genetics may all play a role in the development of COPD, for instance, he said.
In addition, Jiang said that because this is a cross-sectional study rather than a longitudinal one -- meaning that it looks at a collection of individuals at a single point in time instead of following the same individuals over an extended period -- "we cannot say cured meat is associated with an increased risk of developing COPD, only that people who ate cured meat were more likely to have it."
Neither Jiang nor Schachter recommended wholesale dietary changes as a result of this study, and neither did Cathy Nonas, a registered dietician and director of diabetes and obesity programs at North General Hospital in New York City. "Would I tell people not to ever eat lunch meats again?" she said, "No, I wouldn't."
But, Nonas added, the study "does play up the idea that fresh foods are probably still better for you. And that a moderate amount of all of these things (cured meats) is certainly better than too much."
Jiang and colleagues have now completed two independent, prospective studies on the relationship between cured meat consumption and COPD, which, Jiang said, confirmed the findings in this report. Both studies have been submitted for publication, Jiang added.
For more information on COPD, visit the American Lung Association.