Node Smith, ND

Most people know that smoking is hazardous to health, that it contributes to heart disease and lung cancer, as well as cellular breakdown. Many people who currently smoke may think that these risks are inherent in anyone who has ever smoked, and that quitting doesn’t necessarily change these risks. It is true that quitting smoking doesn’t eliminate your risk for lung cancer, however after five years, this risk significantly decreases and continues to drop the longer a person has been a non-smoker.

Framingham Heart Study

These are conclusions noted in a new study analyzing data from the Framingham Heart Study and published in the Journal of the National Cancer Institute.

The authors of this study hope that the “fact that lung cancer risk drops relatively quickly after quitting smoking, compared to continuing smoking [will] give new motivation” for smoking cessation.

The Framingham study looked at health records from residents of Framingham, Massachusetts, following them for decades. It was supported by the National Heart, Lung, and Blood Institute and was key in establishing hypertension and high cholesterol as risk factors for cardiovascular disease. The study also tracked cancer outcomes.

Current study analyzed 8,907 participants from that original study

The current study analyzed 8,907 participants from that original study, who had been followed between 25 and 35 years. 284 lung cancers were diagnosed during this time period. Roughly 93 percent of the lung cancers occurred in heavy smokers – individuals having smoked at least 1 pack of cigarettes daily for 21 years.

Study found that five years after quitting, previously heavy smokers risk of lung cancer dropped by 39 percent, in comparison

The study found that five years after quitting, previously heavy smokers risk of lung cancer dropped by 39 percent compared to current smokers. The decrease in risk continued to drop as well. However, even 25 years quitting, risk of developing lung cancer for previously heavy smokers was still three times higher than those who had never smoked.


  1. Tindle HA, Duncan MS, Greevy RA, et al. Lifetime Smoking History and Risk of Lung Cancer: Results From the Framingham Heart Study, JNCI: Journal of the National Cancer Institute,
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Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.

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