Smoking’s Disease Burden: Worse than Previously Thought?
March 16, 2015, by NCI Staff
Smoking cigarettes may be even worse for your health than previously thought, according to findings from a new study.
The latest U.S. Surgeon General’s Report on smoking estimates that smoking causes 480,000 deaths annually in the United States. The new study, published February 12 in the New England Journal of Medicine, suggests that smoking may be responsible for an additional 60,000 to 120,000 deaths each year.
To conduct the observational study, investigators from the American Cancer Society (ACS), NCI, and several other institutions pooled data on more than 900,000 men and women, 55 years of age and older, from five contemporary U.S. cohort studies.
From 2000 through 2011, more than 180,000 deaths occurred in people who had participated in the studies.
The rates of death from any cause were nearly three times higher in participants who currently smoked than in participants who never smoked. About 83 percent of the higher death rates in smokers were due to 21 diseases that are known to be caused by cigarette smoking. The remaining 17 percent, however, were due to other causes, Brian Carter, M.P.H., of ACS, and his colleagues reported.
“We estimate that smoking causes at least half of the remaining 17 percent through diseases that have not previously been recognized as being caused by cigarette smoking,” said Neal Freedman, Ph.D., a co-investigator on the study from NCI’s Division of Cancer Epidemiology and Genetics. These include intestinal ischemia, renal failure, hypertensive heart disease, infections, and cancer of unknown site.
“As a result of these diseases, smoking may cause an additional 60,000 deaths per year,” Dr. Freedman added. Smokers were at higher risk of other diseases in the study as well, including breast and prostate cancer, although the investigators wrote that more research is needed for these endpoints.
There was some good news in the study, however. Consistent with earlier findings, although the risk of death increased significantly with greater smoking intensity, it “declined after cessation of smoking,” the research team wrote.
The study has several limitations, they noted, including that most participants in the cohort studies were white and that the associations between smoking and mortality “could be confounded by differences between smokers and nonsmokers with respect to risk factors including diet, physical activity, and access to medical care.”
The study’s findings underscore the need for continued efforts to reduce the number of people who smoke, wrote Graham Colditz, M.D., of the Washington University School of Medicine, in an accompanying editorial.
“It is understandable that many people view smoking as a war that we have won, given the large decreases in smoking rates since the 1960s,” Dr. Colditz wrote. “Although there have been some major victories, the findings of Carter et al. show that the war is far from over. Tobacco remains a large and often insidious health burden.”