Other Lifestyle Factors

Not smoking, using sun protection, and getting vaccinated are among the recognized steps that can lower risk for many cancers.

Smoking and Cancer

Smoking tobacco is the leading cause of cancer worldwide, causing almost 6 million deaths each year. All of these deaths could be prevented if people did not smoke.

Tobacco smoke contains a number of known carcinogens – substances that cause cancer. Many people know that smoking causes lung cancer, but it can also cause many other types, including breast, colorectal, blood, bladder, liver, mouth, pancreatic and stomach cancer. Passive smoking (being exposed to someone else’s tobacco smoke) also increases the risk of lung cancer and is particularly dangerous for children.

All forms of tobacco cause cancer regardless of whether it is chewed; smoked, such as pipes, cigars, “light” cigarettes, roll-ups and shishas; or sucked and inhaled, such as smokeless tobacco and betel quid.

E-cigarettes (“vaping”) do not contain tobacco but there is conflicting information about their safety. They are not regulated, and their long-term impact on health is not yet known.

Not smoking or giving up smoking is the best way to reduce your own cancer risk and the risk to those around you, followed by maintaining a healthy weight, eating a healthy diet, and keeping active.

There is a lot of free information and support available to help with giving up smoking, from the National Institutes of Health and related factsheets from the Centers for Disease Control and Prevention.

Sun, Vitamin D, and Cancer

The majority of skin cancer cases are caused by too much exposure to ultraviolet (UV) radiation from the sun and, increasingly, from sunbeds. Between 2 and 3 million skin cancers occur globally each year, and rates are rising. Melanoma, which is the least common but most serious type of skin cancer, causes the majority of deaths from the disease. The risk of melanoma rises with age, but it is increasingly one of the most common cancers among young people.

Most cases of skin cancer could be prevented by avoiding overexposure to UV rays. UVA and UVB are the two main types of sun rays, and both cause skin cancer by damaging the DNA in our skin cells. Some groups of people are more at risk of the skin damage that leads to skin cancer than others, including children and those with fair skin or red or light-colored hair. Sunburn also increases the risk of skin cancer; getting a sunburn just once every two years can triple your risk of melanoma. So if you’ve had sunburn in the past you need to do more to protect your skin in the future.

The best ways to enjoy the sun safely and protect yourself from sun damage that could lead to skin cancer are: not staying in the sun too long, especially between 11 am and 3 pm between March and October; applying high-factor sunscreen frequently; and wearing a hat, sunglasses, and clothes that cover your arms and legs. It’s important to protect your skin even when you already have a tan. Avoid using sunbeds or tanning booths. Fake tan is safer than using sunbeds, but Melanotan injections are illegal and unsafe.

Vitamin D  -- Some people can get enough vitamin D by enjoying the sun safely and, as it is also found in foods, by eating a healthy diet. 

People who have a higher risk of vitamin D deficiency are being advised to take a supplement all year round.

Visit the National Institutes of Health for more information on sunlight and cancer.

Infections and Cancer

Many people don’t realize that infections can be associated with cancer, but almost a fifth of cancers worldwide are caused by viral, bacterial or parasitic infections. Those most commonly associated with an increased cancer risk are the human papilloma virus (HPV), hepatitis B (HBV) and C (HCV), and the bacterium Helicobacter pylori (H pylori).

  • HPV -- HPV is a common infection, but there are some high-risk types of the virus which can lead to several cancers, including cervical and anal. It is spread through close skin-to-skin contact, usually during sexual activity. Using a barrier method of contraception reduces the risk. Vaccination is also effective where available: for example, girls in the UK (aged 12-13) and the US (11-12) are offered vaccination against the types of HPV that cause the majority of cervical cancers.
  • HBV and HCV -- Infection with HBV or HCV can cause liver cancer. These can be passed on through blood and other bodily fluids, most commonly through sexual activity or sharing needles to inject drugs. In most countries, young children are offered routine vaccination against HBV. The risk can also be reduced by practicing safe sex and not sharing needles.
  • H pylori -- Infection with H pylori, a type of bacterium that grows in the inside layer of the human stomach, is very common worldwide, especially in low and middle-income countries. Usually acquired during childhood, it is spread through contaminated food and water and direct mouth-to-mouth contact. It increases the risk of stomach cancer. It can also cause stomach ulcers. Infection with H pylori can be treated, so it’s important to talk to your doctor if you have stomach problems or ulcers.
  • HIV -- People infected with the Human Immunodeficiency Virus (HIV) are also at an increased risk of some cancers, including Kaposi sarcoma, lymphoma, liver, and lung. Treatment for HIV is available, so anyone who thinks they are at risk should talk to their doctor about being tested.