4 Shocking Ways Smoking Affects Your Body

Read on for more reasons to quit.

closeup of a woman smoking a cigarette

Updated on September 29, 2023

Smoking kills about 480,000 people every year and is a contributor to three of the five leading causes of death in the United States: heart disease, cancer, and stroke. If you need even more reasons to quit, here are four surprising facts to consider—plus one piece of good news.

Smoking changes your DNA

Research has shown that smoking causes changes to the DNA of cells through a process called methylation. Methylation is when DNA is chemically modified in a way that causes changes to remain even when cells divide and reproduce. DNA methylation may work by turning on and off the production of proteins encoded by the gene.

One 2016 study published in Circulation: Cardiovascular Genetics that looked at cigarette smokers suggested that the changes to cells’ DNA caused by methylation may remain for more than 30 years in some cases. Several more recent studies have further described the effects of methylation.

A 2021 meta-analysis published in Clinical Epigenetics demonstrated how certain methylated biomarkers could show whether a person had been exposed to cigarette smoke. A 2022 review published in the International Journal of Molecular Sciences confirmed that DNA methylation caused by smoking can be a marker for diagnosing and treating smoking-related cancers.

Smoking may cause methylation in about one-third of known genes. The one glimmer of hope? Most of these genes may go back to normal by five years after quitting smoking.

Cigarette smoke contains an obscene number of chemicals

Here are some of the 7,000 chemicals contained in either tobacco or tobacco smoke:

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

According to the U.S. Environmental Protection Agency, cigarettes also contain radioactive materials, including toxic polonium-210 and lead-210, which are byproducts of radon found in fertilizers and soil. These may remain on tobacco leaves during processing.

If you think e-cigarettes or vaping are less toxic, think again. In addition to containing nicotine, the flavoring chemicals in vapes can irritate the lungs. The vape’s carrier, or liquid (such as propylene glycol) can also be toxic and irritating. When heated, that liquid may also create traces of acetone and formaldehyde. To top it off, the metal tanks used in vapes can degrade after many rounds of heating, which may release toxic metals into your lungs over time.

Smoking can cause conception and sexual problems

In 2011, a landmark review of 50 years of studies confirmed that smoking during pregnancy can cause major birth defects. Many smokers don’t even make it as far as having children, however. Smoking can impair proper hormone production and cause damage DNA in sperm, reducing the chances of conceiving and potentially resulting in genetic mutations in children.

Impaired hormone production resulting from smoking can also cause sexual dysfunction in people assigned female at birth. Smoking also contributes to erectile dysfunction in those assigned male at birth.

Smoking affects your entire body

You probably already know that smoking can cause or contribute to lung cancer, heart disease, and stroke. But what about the rest of the body?

According to the Centers for Disease Control and Prevention (CDC), smoking raises your risk of type 2 diabetes by 30 to 40 percent. Smoking also hurts your eyes. If you smoke, your risk of age-related macular degeneration doubles and you’ll be two to three times more likely to get cataracts.

Smoking can even aggravate your back. Smoking has been found to be a risk factor for developing chronic low back-pain in some research studies.

Smoking also raises your risk for other cancers throughout the body. For example, smokers have roughly twice the risk of cervical cancer as those who don’t smoke, and secondhand smoke also increases the risk. Other cancers caused by smoking include (but are not limited to) cancers of the esophagus, bladder, blood, liver, pancreas, mouth, kidney, and colon.

Smoking rates are at an all-time low

According to the CDC, in 2021 (the most recent year for which data were available), 11.5 percent of Americans aged 18 or older smoked. That’s about 28.3 million people. It’s still a large number, but the good news is that the percentage has been declining. In 2005, by comparison, nearly 21 percent of U.S. adults smoked.

More good news: Many of the health risks caused by smoking go away after you quit.

  • Your risk of a heart attack goes down dramatically one to two years after quitting.
  • In three to six years after quitting, your added risk of coronary heart disease is halved.
  • In five to 10 years of quitting, your added risk of mouth and throat cancers are half of what they were when you smoked.
  • In 10 years of quitting, your added risk of lung cancer decreases by half and your risk of bladder, esophagus, and kidney cancers lowers.
  • In 15 years after quitting, your risk of coronary heart disease is the same as someone who doesn’t smoke.

Some benefits happen even quicker: After quitting, your sense of smell and taste will improve right away, you’ll experience less coughing and shortness of breath, and your circulation will improve,

Don’t wait. Quit today.

Article sources open article sources

Centers for Disease Control and Prevention. Tobacco-Related Mortality. Page last reviewed April 28, 2020.
Centers for Disease Control and Prevention. Leading Causes of Death. Page last reviewed January 18, 2023.
National Human Genome Research Institute. Methylation. Page last updated September 6, 2023.
Joehanes R, Just AC, Marioni RE, et al. Epigenetic Signatures of Cigarette Smoking. Circ Cardiovasc Genet. 2016 Oct;9(5):436-447.
Christiansen C, Castillo-Fernandez JE, Domingo-Relloso A, et al. Novel DNA methylation signatures of tobacco smoking with trans-ethnic effects. Clin Epigenetics. 2021 Feb 16;13(1):36.
Besaratinia A, Caceres A, Tommasi S. DNA Hydroxymethylation in Smoking-Associated Cancers. Int J Mol Sci. 2022 Feb 28;23(5):2657.
Zong D, Liu X, Li J, Ouyang R, Chen P. The role of cigarette smoke-induced epigenetic alterations in inflammation. Epigenetics Chromatin. 2019;12(1):65.
American Lung Association. What’s in a Cigarette? Page last updated May 31, 2023.
Environmental Protection Agency. Radioactivity in Tobacco. Page last updated August 18, 2023.
Gordon T, Karey E, Rebuli ME, Escobar YH, Jaspers I, Chen LC. E-Cigarette Toxicology. Annu Rev Pharmacol Toxicol. 2022 Jan 6;62:301-322.
Hackshaw A, Rodeck C, Boniface S. Maternal smoking in pregnancy and birth defects: a systematic review based on 173 687 malformed cases and 11.7 million controls. Hum Reprod Update. 2011 Sep-Oct;17(5):589-604.
U.S. Food & Drug Administration. How Smoking Affects Reproductive Health. Page last updated November 9, 2021.
Salari N, Hasheminezhad R, Abdolmaleki A, et al. The effects of smoking on female sexual dysfunction: a systematic review and meta-analysis. Arch Womens Ment Health. 2022 Dec;25(6):1021-1027.
Allen M, Tostes R. Cigarette smoking and erectile dysfunction: an updated review with a focus on pathophysiology, e-cigarettes, and smoking cessation. Sexual Medicine Reviews. 2023 Jan;11(1):61–73.
Centers for Disease Control and Prevention. Smoking and Diabetes. Page last reviewed May 5, 2022.
Centers for Disease Control and Prevention. Vision Loss, Blindness, and Smoking. Page last reviewed May 5, 2022.
Nieminen LK, Pyysalo LM, Kankaanpää MJ. Prognostic factors for pain chronicity in low back pain: a systematic review. Pain Rep. 2021 Apr 1;6(1):e919.
Green BN, Johnson CD, Snodgrass J, Smith M, Dunn AS. Association Between Smoking and Back Pain in a Cross-Section of Adult Americans. Cureus. 2016;8(9):e806. Published 2016 Sep 26.
National Cancer Institute. Cervical Cancer Prevention - Health Professional Version. Page last updated April 10, 2023.
Centers for Disease Control and Prevention. Smoking and Cancer. Page last reviewed May 5, 2022.
Centers for Disease Control and Prevention. Current Cigarette Smoking Among Adults in the United States. Page last reviewed May 4, 2023.
Centers for Disease Control and Prevention. Benefits of Quitting. Page last reviewed September 23, 2020.
American Cancer Society. Health Benefits of Quitting Smoking Over Time. Page last updated November 10, 2020.

Featured Content


5 Ways to Overcome Cigarette Cravings

Quitting is hard, but not impossible.

Shocking Smoking Facts That Will Make You Want to Quit Today

Smoking not only causes cancer and heart and lung disease, but it’s associated with stress, reproductive problems and more.


Develop a Quit Smoking Plan That Really Works

Robin Miller, MD, explains why your doctor should be part of your smoking cessation team.

6 Unexpected Side Effects of Smoking

Cigarettes affect your health and appearance in surprising ways.