Men and women who quit smoking by the age of 40 reduce the mortality risks of smoking by as much as 90%, gaining back as many as 9 of the 10 years they would lose by continuing to smoke, according to a new article published in the New England Journal of Medicine.
Researchers analyzed data from a cohort of 216,917 adults in the U.S. National Health Interview Survey (NHIS) between 1997 and 2004 that were linked to the National Death Index.
The analysis found that smokers live 10 years less than people who don’t smoke, but those who stop smoking will prolong their life no matter what age they quit.
In fact, smokers who quit by age 40 erase nearly all of the excess mortality risks associated with continued smoking, according to the study.
The results of smoking cessation by age range are as follows:
- For smokers who quit at 25 to 34 years of age (median, 29), survival rates were nearly identical to non-smokers, which means that those who quit smoking gained about 10 years of life, as compared with those who continued to smoke.
- Smokers who quit at 35 to 44 years of age (median, 39) reduced their excess risk of death by about 90%, gaining about 9 years of life compared to those who continued to smoke.
- Smokers who quit at 45 to 54 years of age (median 49) gained about 6 years of life.
- Smokers who quit at 55 to 64 years of age (median 59) gained about 4 years of life.
Overall, the risk of death for all smokers, ages 25 to 79, was about 3 times as great as those who had never smoked, the article said. Data found that, compared to non-smokers, survival was shorter by about 11 years for female smokers and by about 12 years for male smokers.
Researchers also concluded that smokers are 50% less likely to reach age 80, compared to non-smokers. For women, the chance of surviving to age 80 was 70% for non-smokers and 38% for smokers. For men, the probability was 61% for non-smokers and 26% for smokers.
Researchers recommended several steps to increase cessation rates and decrease initiation rates of smoking worldwide, which killed about 100 million people in the 20th century and — based on current rates of smoking initiation and cessation — will kill about 1 billion in the 21st century, according to the article.
The full study was published in the New England Journal of Medicine and is available on its website.