smoking

Study: Smoking-Related Mortality Greatly Underestimated

The number of annual smoking-related deaths has been greatly underestimated, according to a recent study.

“Most [smoking-related mortality] is believed to be explained by 21 common diseases that have been formally established as caused by cigarette smoking and are included in official estimates of smoking-attributable mortality in the United States,” researchers explained.
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“However, if smoking causes additional diseases, these official estimates may significantly underestimate the number of deaths attributable to smoking.”

In their study, researchers followed 421,378 men and 532,651 women (55 years or older) enrolled in 1 of 5 US cohort studies from 2001 to 2011, during which time, there were 181,377 deaths. Of those, 16,475 were current smokers.

Overall, 17% of the deaths among current smokers were related to conditions not previously attributed to smoking, including renal failure (relative risk, 2.0), intestinal ischemia (relative risk, 6.0), infections (relative risk, 2.3), hypertensive heart disease (relative risk, 6.0), breast cancer (relative risk, 1.3), prostate cancer (relative risk, 1.4) and various respiratory diseases (relative risk, 2.0).

The investigators noted that among former smokers, the relative risk for the aforementioned outcomes waned as the time from cessation passed.1

“The number of additional deaths potentially linked to cigarette smoking is substantial,” they wrote.

“In our study, many excess deaths among smokers were from disease categories that are not currently established as caused by smoking, and we believe there is strong evidence that many of these deaths may have been caused by smoking.  If the same is true nationwide, then cigarette smoking may be killing about 60,000 more Americans each year than previously estimated, a number greater than the total number who die each year of influenza or liver disease,” he said.

The complete study is published in the February issue of the New England Journal of Medicine.

-Michelle Canales Butcher

References:

1. American Cancer Society. Tobacco may cause more deaths than currently estimated [press release]. February 11, 2015. http://pressroom.cancer.org/SmokingDeathsNEJM2015. Accessed February 12, 2015.