The Good News and Bad News When You Quit Smoking

By Dr. Joseph Mercola

Contributing writer for Wake Up World

Although the good news is your body begins healing within an hour of your last cigarette, research has also found risk of lung cancer continues to be threefold higher 25 years after quitting compared to those who have never smoked.

Nearly 40 million American adults smoke cigarettes.1 It is the leading cause of preventable death in the U.S., accounting for 1 out of every 5 deaths each year. According to Memorial Sloan-Kettering Cancer Center, 130,000 cases of lung cancer diagnosed each year are attributed to smoking.2

About 50 years ago, nearly 42 percent of the population smoked cigarettes,3 but between 2005 and 2014 those numbers dropped to nearly 17 percent and then to 15 percent by 2015.4 Public health officials hope this number continues to drop each year.

If you smoke, quitting is an essential strategy to returning to good health, as smoking is linked to a number of chronic diseases, including cancer, heart disease and stroke. However, smoking affects nearly every organ in your body, and so your bones, brain, teeth, eyes and even fertility may all be damaged. Your body does have an amazing ability to heal, though.

Once you stop smoking you’ll experience beneficial changes in the following days, weeks and years, as your body clears out the damage done by nicotine and the hundreds of other chemicals found in cigarettes. That’s the good news. The bad news is you may never be able to completely outrun the damage incurred from smoking in your lifetime.5

Quarter Century Later, Risk of Lung Cancer Still Elevated

Your lung cancer risk drops substantially within the first five years you quit smoking. However, the team from Vanderbilt University also discovered the risk of lung cancer compared to current smokers was still three times higher than those who had never smoked, 25 years after quitting. Senior research author Dr. Matthew Freiberg says:6

“While the importance of smoking cessation cannot be overstated, former heavy smokers need to realize that the risk of lung cancer remains elevated for decades after they smoke their last cigarette, underscoring the importance of lung cancer screening.”

These are the main findings from a new analysis of the Framingham Heart Study. Researchers evaluated 907 health records of residents from Framingham, Massachusetts, who were followed between 25 and 34 years.7 During this time, 284 individuals were diagnosed with lung cancer, nearly 93 percent of which occurred in those who were identified as heavy smokers before they quit. Heavy smokers were defined as those who smoked at least a pack of cigarettes of day for 21 years or more.

The researchers discovered five years after quitting, the risk of developing lung cancer dropped by 39 percent compared to current smokers, and continued to fall as time went on.8 However, the risk remained over threefold higher at the 25-year mark, compared to people who had never smoked. These results are not unexpected as every cigarette damages DNA in the body, not only the lining of the lungs but in other cells, leading to the association of smoking with 16 different types of cancer.

Researchers have identified changes in your DNA, called methylation, affecting how the genes are expressed or modified to affect your health.9 In some cases methylation tells the genes to turn “off,” effectively changing how your body responds to its environment. This is a signaling tool for gene expression vital to a number of cell processes controlling human disease.

Researchers have been able to demonstrate the alterations to DNA methylation caused by smoking may last up to 30 years. The amount of damage and the consequences are the planned focus of further study.10 While much of the DNA reverts to the original state after a smoker quits, some remains changed decades later and may be associated with the development of chronic disease and the development of cardiovascular disease,11 obesity and diabetes in adulthood.

Smoking Increases Potential Risk of Death and Disease

Worldwide, tobacco continues to be the leading cause of preventable death, causing nearly 6 million deaths each year.12 According to the Centers for Disease Control and Prevention (CDC), current trends show tobacco will cause more than 8 million deaths by 2030.13 In 2016, 15 percent of all adults smoked combustible cigarettes and each day more than 3,200 people younger than 18 smoke their first cigarette.

In the United States, smoking causes more deaths every year than a combination of HIV, illegal drug use, alcohol use, motor vehicle accidents and firearm-related incidents.14 Estimates show15 smoking increases the risk for coronary heart disease up to four times, the risk of stroke up to four times and the risk of lung cancer up to 25 times, compared to those who have never smoked.

Smoking also makes it more difficult for a woman to become pregnant and affects her baby’s health before and after birth and, for everyone, increases risk of tooth loss, cataracts and Type 2 diabetes.16 According to the World Health Organization (WHO), while many people are aware of the link between smoking, cancer and respiratory conditions, many are unaware of its links to heart attacks and strokes. According to WHO chief Tedros Adhanom Ghebreyesus:17

“Most people know that using tobacco causes cancer and lung disease, but many people aren’t aware that tobacco also causes heart disease and stroke — the world’s leading killers. Tobacco doesn’t just cause cancer. It quite literally breaks hearts.”

Although fewer people are smoking worldwide, WHO believes only one country in eight is on track to meet a target of reducing tobacco use significantly by 2025.18 They sealed a landmark treaty in 2005, ratified by 180 countries, calling for a ban on tobacco advertising and sponsorship, and taxes to discourage use. While WHO recognizes there has been progress, Douglas Bettcher, director of WHO’s prevention of noncommunicable diseases, said:19

“One of the major factors impeding low- and middle-income countries certainly is countries face resistance by a tobacco industry who wish to replace clients who died by freely marketing their products and keeping prices affordable for young people.”

He recognizes industrialized countries are making faster progress than developing countries and kicking the habit is a challenge. At this time, America is the only region set to meet a target of 30 percent reduction in tobacco use by 2025 compared to use in 2010. WHO has said use in the Middle East is actually increasing while parts of Western Europe have reached a standstill.20

WHO Concerned Not All Aware of Heart Risk Associated With Smoking

As concerning to the organization as reducing numbers of individuals who smoke, are the number of people in China and India who are unaware of the fact that smoking increases their risk of heart disease and stroke.21 To date, China and India have the highest number of smokers worldwide, followed by Indonesia. Bettcher commented:22

“The percentage of adults who do not believe smoking causes stroke are for example in China as high as 73 percent, for heart attacks 61 percent of adults in China are not aware that smoking increases the risk. We aim to close this gap.”

A survey done by WHO showed more than half of adults in India and Indonesia are unaware smoking can cause a stroke.23 According to their report on trends and prevalence, the percentage of those who smoke worldwide has dropped from 27 percent in 2000 to 20 percent in 2016. However, due to population growth, the actual numbers who smoke have remained relatively stable.


E-Cigarette Use on the Rise

As tobacco companies began losing clients with the push to quit smoking, the modern e-cigarette was modified and marketed. First sold in 2007 in the United States, their global use has risen exponentially.24 The popularity is likely associated with the difference between traditional combustible cigarettes emitting an offensive odor while electronic cigarettes are relatively odorless and therefore generally misperceived as safe and harmless.

However, with mounting evidence of health risks and the highly addictive nature of nicotine, a coalition of respiratory physicians and scientists from six continents is calling for an immediate ban on flavorings and of marketing e-cigarettes to adolescents and children.25 The Forum of International Respiratory Societies is a collaboration of organizations across North and South America, Europe, Africa, Asia and Australia.

The coalition seeks to bring together a range of research highlighting the susceptibility of children and adolescents to nicotine addiction and recommends how to protect youth from its harmful effects. The authors cite evidence e-cigarettes are a bridge to traditional combustible cigarette smoking and adolescents. Dr. Thomas Ferkol, professor of pediatrics and cell biology at Washington University, commented:26

“Until recently, the risks of e-cigarettes and the rising popularity with children and adolescents were under recognized or ignored. We wrote this statement to address growing public health concerns over e-cigarette use among the youth. Product design, flavors, marketing and perception of safety and acceptability have increased the appeal of e-cigarettes to young people.

These products are normalizing smoking and leading to new generations addicted to nicotine. Some people truly believe these cigarettes could be used as a smoking cessation technique, but these products also are an entry to nicotine addiction and tobacco use in young people.”

According to statistics from WHO,27 there’s been a rapid increase in the number of individuals vaping between 2011 and 2016, rising from 7 million to 35 million in five years. The global product market is estimated to be worth $22.6 billion, up from $4.2 billion just five years ago. In a report published by Ernst & Young,28 the number of e-cigarette users in seven countries surveyed grew 86 percent between 2013 and 2015, with the total highest usage in Great Britain and France.

In 2015, 37 percent of e-cigarette users identified themselves as ex-smokers, an increase from 31 percent from 2013. The growth in flavors and nicotine strength is in response to evolving consumer preferences, and the majority of devices and liquid are purchased at specialty stores. Interestingly, the report also found countries with higher cigarette prices tend to have a higher penetration of e-cigarette use in the population.29

Vaping is Not a Healthy Alternative

Whether used by children or adults, vaping is only a short-term alternative to smoking combustible cigarettes if you’re trying to quit, since the product carries significant health risks. Smokeless e-cigarettes are the most popular nicotine-based product used by high school and middle school students. The 2016 Surgeon General’s Report30 showed a 900 percent increase in use of this product between 2011 and 2015.

Several studies have supported the belief e-cigarettes are a gateway habit, leading teens from vaping to smoking traditional combustible cigarettes, hookah and cigars.31,32,33 In other studies using animal models,34 researchers have discovered rats exposed to nicotine during adolescence grew into adulthood with a greater potential to exhibit addictive behavior.

The researchers found exposure to nicotine at a young age changes the neurological circuitry in the brain within the reward center. Long-term changes in the midbrain reward center may also be a gateway to other addictive drugs, such as cocaine, heroin and morphine.35

In an examination of e-cigarette devices, researchers from Johns Hopkins Bloomberg School of Public Health36 found a significant number generated unsafe levels of lead, nickel, chromium and magnesium, consistent with previous studies. Nearly 50 percent of the vapor samples to which bystanders are exposed had lead concentrations higher than limits set by the Environmental Protection Agency.37

Despite lower levels of nicotine pollution from e-cigarettes, researchers have found bystanders have similar levels of cotinine, a measure of the amount of nicotine taken into the body, as those who are exposed to traditional combustible secondhand cigarette smoke.38 Vapor also contains acetaldehyde and formaldehyde39 and the U.S. Food and Drug Administration has detected antifreeze chemicals in e-cigarettes, which are linked to cancer.40

I believe the secret to quitting smoking is to first get healthy, making quitting mentally and physically easier. Exercise, eating right and getting plenty of sleep are important parts of this plan. You can read more in my previous article, “The Vaping Epidemic Is Getting Out of Hand.”

Sources and References:

Recommended articles by Dr. Joseph Mercola:

About the author:

Born and raised in the inner city of Chicago, IL, Dr. Joseph Mercola is an osteopathic physician trained in both traditional and natural medicine. Board-certified in family medicine, Dr. Mercola served as the chairman of the family medicine department at St. Alexius Medical Center for five years, and in 2012 was granted fellowship status by the American College of Nutrition (ACN).

While in practice in the late 80s, Dr. Mercola realized the drugs he was prescribing to chronically ill patients were not working. By the early 90s, he began exploring the world of natural medicine, and soon changed the way he practiced medicine.

In 1997 Dr. Mercola founded, which is now routinely among the top 10 health sites on the internet. His passion is to transform the traditional medical paradigm in the United States. “The existing medical establishment is responsible for killing and permanently injuring millions of Americans… You want practical health solutions without the hype, and that’s what I offer.”

Visit for more information, or read Dr. Mercola’s full bio and resumé here.

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