“There’s no one who doesn’t know the risks,” says Peter Shields, MD, a professor of internal medicine and epidemiology at the Ohio State University in Columbus. But, he says, nicotine is incredibly powerful. Teens start smoking to mimic their parents and peers. Quickly, they become addicted and can’t stop.
How Does Smoking Lead to So Many Cancers?
“If you’re smoking, you’re bathing your lungs in these carcinogens (cancer-causing substances),” he says.
Changes in DNA
One way that smoking causes cancer is by altering DNA, the genetic information that directs the function of our cells, says Shields. Normally, cells finish their jobs and die off. Chemicals in cigarette smoke change DNA in ways that prevent cells from dying. “They become immortal, and then they replicate,” says Shields.
Free Radical Damage
Smoking also causes inflammation, an important contributor to cancer development. And it depletes antioxidants, which are protective substances that neutralize free radicals (unstable molecules that cause disease, including cancer). “(Antioxidants are) our defense against harmful agents, so it makes the smoker more susceptible to other carcinogens,” explains Anthony Alberg, PhD, MPH, an epidemiologist at the University of South Carolina Arnold School of Public Health in Columbia who studies the health effects of tobacco.
How Do Cigarette Toxins Reach So Many Organs?
Cancer-causing chemicals can also get into the urine. “For bladder cancer, the thinking is that the carcinogens remain in urine and are interacting with the bladder tissue in ways that could ultimately cause (DNA) mutations and lead to cancer,” says Dr. Alberg.
Smoking isn’t linked to other types of cancer, however, like breast and prostate. The reason for this isn’t clear, but it could have to do with how much of the toxins from cigarette smoke reach those organs, Alberg says.
Are Genes Linked to Greater Risk for Smoking-Related Cancers?
Why is it that some people can smoke three packs a day and not get lung cancer, while others smoke far less and do get cancer? The answer likely lies in our genes. Certain genes affect the ability to break down carcinogens and other toxins, says Alberg.
But you can’t look to relatives for clues to your smoking-related cancer risk, he says. Just because your parent or sibling smoked for years and didn’t get cancer, doesn’t mean you’ll be as lucky.
Is Social Smoking Safe?
What if you have the occasional cigarette with your cup of coffee or glass of wine? The cancer risk from smoking is dose-dependent, meaning the more cigarettes you smoke and the longer you smoke, the greater your risk of getting cancer.
Social smoking is undoubtedly less harmful than a three-pack-a-day habit. On the other hand, as Albert stresses, “There’s no safe level of exposure to tobacco smoke.”
How Does Secondhand Smoke Affect Cancer Risk?
How Safe Is Smokeless Tobacco?
Reasons to Quit — and How to Kick the Habit
Quitting smoking at any age is good for your health. “The impact is almost immediate,” says Shields. The longer you’ve been off smoking, the more your cancer risk drops.
Anyone who wants to quit smoking can find help from many different resources: quit helplines (1-800-QUIT-NOW), apps such as QuitGuide and quitSTART, counseling, nicotine replacement products, and medications like varenicline (Chantix) and bupropion.
“There are lots of resources out there. Sometimes people just need to understand their cues — why they’re smoking,” Shields says. “It’s much harder for some (people to quit) than others, but everybody can do it.”
The Takeaway
Decades of research show that smoking is linked to 12 types of cancer and other serious health conditions. If you smoke, each puff exposes your body to thousands of harmful chemicals, increasing cancer risk significantly. Remember, quitting smoking even now can dramatically cut your cancer risk in the coming years.
