For smokers, deaths with a cardiovascular or cancer-related cause, or ones that can be attributed to a respiratory disease such as chronic obstructive pulmonary disease, are significantly more common than for nonsmokers. It is widely recognized that stopping smoking leads to a reduction in mortality risk. To make reliable statements on the timeline of this reduction, researchers analyzed interview data and death rates from 438,015 adult US citizens from 1997 to the end of 2019.
The analyses show that it takes 30 years for the mortality risk of ex-smokers to resemble that of people who never regularly smoked. Blake Thomson, PhD, and Fahrad Islami, MD, PhD, both members of the Department of Surveillance and Health Equity Science of the American Cancer Society in Atlanta, Georgia, published their results as a research letter in the Journal of the American Medical Association.
After Smoking Cessation
Overall, 11,860 cardiovascular, 10,935 cancer-related, and 2060 respiratory-related deaths were considered from over 5 million patient years. Taken from these figures, the mortality risks of continuous smokers were 2.3 times (cardiovascular), 3.4 times (cancer-related), and 13.3 times (respiratory-related) higher than those of continuous nonsmokers.
Within 10 years of stopping smoking, the following occurred:
- The cardiovascular mortality risk fell by 1.47 times, compared with nonsmokers (by 36% compared with smokers).
- The cancer-related mortality risk fell by 2.13 times, compared with nonsmokers (by 47% compared with smokers).
- The respiratory-related mortality risk fell by 6.35 times, compared with nonsmokers (by 43% compared with smokers).
- The cardiovascular mortality risk fell by 1.26 times.
- The cancer-related mortality risk fell by 1.59 times.
- The respiratory-related mortality risk fell by 3.63 times — each time compared with nonsmokers.
- The cardiovascular mortality risk fell by 1.07 times.
- The cancer-related mortality risk fell by 1.34 times.
- The respiratory-related mortality risk fell by 2.34 times, compared with nonsmokers.
30 Years Later
Only after more than 30 years of not smoking was the cardiovascular-related mortality risk 0.96 and, therefore, no longer significant. Compared with nonsmokers, the cancer-related mortality risk was 1.16, and the respiratory-related mortality risk was 1.31.
Therefore, former smokers can reduce their cardiovascular mortality risk by 100%, the cancer-related by 93%, and the respiratory-related mortality risk by 97%.
The result reinforces earlier analyses on the reduction in mortality risks by stopping smoking, with fewer participants. Smokers, therefore, benefit more the longer that they can refrain from using tobacco. "The earlier in life that smoking is given up, the better," the authors wrote. But even in the first 10 years, the mortality risks examined decreased by a statistically significant 36% (cardiovascular) to 47% (cancer-related).
An Underestimation?
One disadvantage of the study is that the participants' data were collected using personal questionnaires. For this reason, participants may have reported their tobacco consumption as being lower than it was, particularly because these questionnaires are often answered in hindsight, the authors pointed out.
In addition, some of the participants who reported stopping smoking completely may have only reduced their consumption. However, both circumstances would cause the results of the analysis to be even clearer, compared with reality, and therefore better.
This article was translated from the Medscape German edition.
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