How quickly does your risk of death fall after you quit smoking? It depends on the disease. That's the conclusion of a new study based on data from the Nurses' Health Study. This study tracked 100,000 women for 24 years. Women who quit smoking reduced their risk of death from heart and artery disease by half within five years. But it took 20 years for the risk of death from emphysema to return to normal. It took 30 years for lung cancer. The study was published in the Journal of the American Medical Association. Reuters Health news service wrote about it May 7.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Surely, you've heard this news: Smoking is terrible for your health. But here's a question that's worth asking: What happens to the health of a smoker who quits?

Researchers at the Harvard School of Public Health provide an encouraging answer. They report that within 5 years of quitting, women who quit had a 13% lower death rate than those who continued to smoke.

The study analyzed data from more than 100,000 women. Their health was monitored over 24 years. Among other benefits, those who quit had less artery disease, fewer heart attacks and fewer strokes.

The risk of some diseases took longer to fall than others. For example, stroke risk was slower to come down than heart attack risk. Deaths due to lung cancer dropped 21% within 5 years of quitting. However, it took up to 30 years to see the full benefit of quitting on lung cancer risk.

Among active smokers, 64% of deaths were smoking-related. The rate was 28% among former smokers.

It surprised me that deaths from colorectal cancer were more common among smokers than nonsmokers. Another finding was not surprising at all. The earlier smokers began the habit, the greater the effect on death rates.

These findings should provide additional incentive to quit smoking. Even more importantly, awareness of these findings should discourage potential smokers from starting. Of course, getting the word out in a way that makes a difference is not easy. People who start smoking at a young age tend not to be concerned about risks that might catch up with them decades later.

What Changes Can I Make Now?

The message of this new study is clear: Don't smoke. If you don't smoke now, don't start. And if you do smoke, make a plan to quit, the sooner the better.

If you have tried unsuccessfully to quit on your own, talk to your doctor about ways to quit. Consider one or more of the following approaches that some smokers find helpful:

• Recruit another smoker to quit with you. Let your family and friends know about your plans so they can provide support.
• Contact your local chapter of the American Cancer Society to learn about smoking cessation programs and support groups.
• Keep a positive attitude, even if you are unable to quit right away. For many people it takes more than one try.
• Consider nontraditional approaches. For example, some people quit smoking after getting acupuncture treatments or hypnosis.
• Try one of the nicotine-replacement systems. There are now skin patches, nasal sprays, inhalers, chewing gum and lozenges that contain nicotine. When combined with counseling, they can help prevent nicotine-withdrawal symptoms.
• Consider a prescription medicine such as bupropion (Zyban) or varenicline (Chantix). They can increase the success rate of quitting.

I've known long-term smokers who believe there's little benefit to quitting. They believe "the damage is already done." But according to this new research, that's not necessarily true. At least some of the most important health effects of smoking may be reversible. Many of these health benefits come soon after quitting.

Unfortunately, some smokers may interpret this new research in a way that leads to more smoking. If smoking-related health risks fall quickly after quitting, they may feel less sense of urgency about quitting. I think that would be a mistake.

What Can I Expect Looking to the Future?

You can expect researchers to continue to study the effects of quitting on the health of former smokers. Since study subjects in this latest research were female, it would be useful to know if the rapid drop in health risks applies to men as well. You can also expect to hear more about new ways to quit smoking. These most likely will include medicines, counseling and nicotine-replacement treatments.