5 Essential Facts About Smoking

In case you need more reasons to quit.

woman blowing smoke

Medically reviewed in August 2021

Updated on April 11, 2022

Smoking kills about 480,000 people every year, and is a contributor to four of the five leading causes of deaths in the US: heart disease, cancer, lung disease and stroke. Need another reason to quit? Here are four—plus a piece of good news.

1. Smoking changes your DNA. A 2016 study of nearly 16,000 people published in Circulation: Cardiovascular Genetics suggests that not only does cigarette smoking cause changes to your cells’ DNA through a process called methylation, but some of those changes can stick around for more than 30 years. DNA methylation is part of the process that signals cells to “turn on” genes. Smoking causes methylation in about one-third of known genes. The good news: most of these genes are back to normal by five years after quitting smoking.

2. The chemicals in cigarette smoke read like the contents of an industrial supplies warehouse. Here are just some of the 7,000 chemicals contained in either tobacco or smoke:

  • Nicotine, a potent insecticide
  • Acetone, found in nail polish remover
  • Arsenic, found in rat poison
  • Butane, found in lighter fluid
  • Carbon monoxide, found in car exhaust
  • Formaldehyde, found in embalming fluid
  • Lead, found in batteries
  • Tar, found in blacktop

3. Smoking can cause conception and sexual problems. Since the 1960s it’s been known that smoking can cause birth defects, but many smokers don’t even make it as far as having children. Smoking can impair proper hormone production in women, which may make it more difficult to become pregnant. Men who smoke are more likely to have damaged DNA in their sperm, reducing the chance to conceive. Smoking also impairs blood flow, which can make it difficult for men to get an erection.

4. Smoking affects your entire body. You already know that smoking can cause cancer, lung disease, heart disease and stroke. But what about the rest of the body? It raises your risk of type 2 diabetes by 30 to 40 percent. Postmenopausal women who smoke have weaker bones than non-smokers, and are more susceptible to rheumatoid arthritis. Smoking also hurts your eyes, potentially increasing your risk of cataracts and age-related macular degeneration. Smoking can even aggravate your back—a 2012 study of more than 5,300 people with back pain found that pain went down considerably in people who quit smoking during the study.

5. Smoking rates are at an all-time low. According to data from 2014 (the most recent year available), 16.8 percent of Americans age 18 or older smoked. That’s about 40 million people. That’s a lot, but that percentage has declined every year since 1965, a year after the surgeon general’s first report on smoking. Even smoking among high school students has been on the downslope since 1997.

More good news: Many of the health risks smoking causes go away after you quit. Your risk of heart disease is cut in half a year after you quit. In five years your risk of mouth, throat, esophagus and bladder cancers are half of what they were when you smoke, and in 10 years your risk of lung cancer has been reduced by half. And some benefits happen even quicker: You’ll smell and taste better, your circulation improves, your immune system bounces back and your risk of a sudden heart attack goes down all within the first year after quitting. Don’t wait. Quit today.

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