Decline in excess mortality seen in first decade after quitting smoking

Former smokers avoid more than half of the excess cardiovascular, cancer, and respiratory mortality associated with current smoking within the first decade after quitting, according to a research letter published online Nov. 27 in JAMA Internal Medicine.

Blake Thomson, D.Phil., and Farhad Islami, M.D., Ph.D., from the American Cancer Society in Atlanta, examined the association between years since quitting smoking and mortality. Self-reported current and never smokers were compared to former smokers who had quit one to nine, 10 to 19, 20 to 29, and 30 or more years before recruitment for cardiovascular, cancer, and respiratory deaths at ages 25 to 89 years.

The researchers identified 11,860 cardiovascular, 10,935 cancer, and 2,060 respiratory deaths during 5.0 million person-years of follow-up in the 438,015 included adults. The current- versus never-smoker rate ratios were 2.30, 3.38, and 13.31 for cardiovascular, cancer, and respiratory mortality, respectively. Former smokers avoided an estimated 64%, 53%, and 57% of excess cardiovascular, cancer, and respiratory mortality associated with current smoking within the first decade after quitting, respectively, with further benefits accruing over time.

Little to no excess cardiovascular mortality was seen at 20 to 29 years after quitting among former smokers. Former smokers avoided an estimated 100%, 93%, and 97% of the excess cardiovascular, cancer, and respiratory mortality associated with continued smoking after 30 or more years of smoking cessation, respectively.

"These findings emphasize that with sustained cessation, cause-specific mortality rates among former smokers may eventually approximate those of never-smokers," the authors write.