According to the Centers for Diseases Control and Prevention, roughly 42 million adult Americans smoke – 15% of women and 20% of men. The United States Surgeon General currently has a list of 21 deadly diseases caused by smoking, which result in an estimated 437,000 deaths per year. A recent study in The New England Journal of Medicine, “Smoking and Mortality – Beyond Established Causes,” examined additional diseases, bringing into question the official approximates on the number of deaths attributable to smoking. Researchers combined data from five US cohort studies that followed people from 2000 through 2011 with a joined sample of 421,378 men and 532,651 women age 55 or older, including roughly 89,000 current smokers.
Researchers found that among the study sample, there were 181,377 deaths with 16,475 deaths among current smokers. The most interesting finding was that “approximately 17% of the excess mortality among current smokers was due to associations with causes that are not currently established as attributable to smoking,” adding roughly an additional 60,000 smoking related deaths a year in the United States. In comparison to people who had never smoked, smokers were roughly twice as likely to die from infections, renal failure, respiratory ailments not previously associated with tobacco, and hypertensive heart disease. Smokers were also six times more likely to die from intestinal ischemia, when blood flow is reduced to the intestines. Researchers noted that smokers were 30% more likely to die of breast cancer than nonsmokers and 40% more likely to die of prostate cancer. The study found that the more heavily a person smoked, the greater the additional risk, and for former smokers, the risk decreased over time.
It is important to note that this study was observational, examining people’s smoking habits and the correlation of their smoking behavior and their health. Due to its methodology, the study cannot claim causal links between behavior and health, only claiming associations with smoking. One of the researchers, Dr. Eric Jacobs, proposed potential mechanisms for how smoking can result in some of the illnesses found in the study. For instance, smoking can suppress the immune system, a reason why there are high rates of death by infection among smokers. In terms of kidney disease, smoking has been found to cause diabetes, high blood pressure, and artery disease, which can cause kidney failure. Lung damage due to smoke and increased risk for infection can result in respiratory illnesses. As smokers are also more likely to consume alcohol and high alcohol consumption increases the risk of breast cancer, researchers were cautious to establish a direct link between smoking and breast cancer.
Taking into account the additional 60,000 deaths due to smoking from this study, the total number of smoking related deaths per year in the United States grows to roughly half a million people a year – 1 in 5 deaths overall in the US. While a spokesman for the US Surgeon General has indicated that the official list of 21 diseases caused by smoking will not be changed as a result of this study, going forward, the new findings will be reviewed in future assessments.