Nearly 40% of All Cancers Caused by Preventable Risk Factors

• Researchers identified 30 modifiable factors that influence cancer risk, from smoking to sun exposure.
• More than one-third of cancers in North America were linked to preventable risk factors like tobacco and alcohol use, as well as overweight and obesity and a lack of physical activity.
• Experts recommend regular exercise, a healthy diet, and stress reduction as actionable ways to reduce cancer risk.

Common lifestyle habits like smoking, drinking alcohol regularly, and avoiding exercise can increase cancer risk.

New research found nearly 40% of new cancer cases could have been prevented due to these factors.

The global study, published on February 3 in Nature Medicine, tracked rates of cancer diagnoses in 2022 that were caused by modifiable lifestyle or environmental factors. The most common cancers linked to these factors included lung, stomach, and liver cancers.

Researchers identified 30 “modifiable risk factors” across 185 countries, including:

• smoking tobacco
• drinking alcohol
• having overweight or obesity
• not exercising enough
• chewing tobacco or areca nut
• not breastfeeding or not breastfeeding long enough
• air pollution
• too much sun exposure
• certain infections
• workplace exposures to harmful substances

The Nature Medicine study found that more than one third of new cancers in North America were linked to modifiable risk factors.

“There are so many things people can do to prevent cancer,” said Allison Steinberg, RN, MPH, an oncology nurse and strategic director of cancer prevention and early detection for Prevent Cancer Foundation, who wasn’t involved in the study.

Lung cancer had the most preventable cases globally and in North America, with 1.8 million cases in 2022 linked to modifiable factors. The number one cause: tobacco.

Smoking alone was responsible for more preventable cancers than any other single factor, causing 360,529 cancer cases, or nearly 15% of all new diagnoses.

The study highlighted smoking in North American women is more than double the global average.

“We should do everything we can to educate and inform that tobacco still remains the number one cause of lung cancer and multiple other types of cancers as well,” said Christine Lovly, MD, PhD, who leads the national thoracic oncology program at City of Hope. Lovly wasn’t involved in the study.

But a growing number of lung cancers strike non-smokers. Between 10% and 20% of all lung cancer cases in the United States now happen to people who never smoked or barely smoked, according to data from the Centers for Disease Control and Prevention (CDC).

This means factors beyond tobacco — like air pollution — also drive a significant portion of cases.

“We’re all at risk because we have lungs,” Lovly said.

Being overweight or obese led to 5.2% of all cancer diagnoses in North America.

This risk factor was the second-most important cancer cause for North American women, contributing to 7.1% of their cases.

A lack of physical activity contributed another 1.8% of cancers overall.

While experts say no safe amount of alcohol exists to minimize cancer risk, the study’s findings emphasize that reducing consumption can lower risk.

While it can be difficult to avoid air pollution, there are steps you can take to minimize your exposure, such as remaining indoors as much as possible on days with poor air quality. You can also use filters to improve the air in your home.

Radon gas, a lesser known indoor air pollutant, may lurk in homes at various levels depending on where you live.

The new global study didn’t mention radon specifically, but this odorless, colorless gas is the second leading cause of non-smoking lung cancers in the United States.

Lovly recommended having your home periodically checked for potentially harmful radon levels and install radon mitigation systems as needed.

Ultraviolet radiation caused 4.1% of all cancers in North America, particularly affecting men at 5.1% of their cancer cases.

The research identified intentional use of sun protection and reducing exposure, particularly during childhood, as key methods to reduce skin cancers.

Cervical cancer ranked as the most preventable cancer in females after lung cancer.

Nearly all cases stemmed from infections like the human papilloma virus (HPV), making it one of the most preventable cancers through vaccination and screening.

The study notes that other infections, such as hepatitis B and C, continue to drive liver cancer, particularly in Africa.

The researchers state that increased vaccination rates and disease prevention measures could help lower cancer risks.

Health experts describe wellness as a proactive strategy built on three essential pillars that work together to prevent disease:

• physical activity
• a healthy diet
• stress reduction

“I think wellness is trying to prevent illness, not treat it,” Lovly said. She frames lifestyle choices as powerful medicine. “Food is medicine, exercise is medicine, sleep is medicine.”

The following recommendations can help you maintain and improve overall health and lower your risk of cancer.

Experts emphasized that physical activity isn’t just about losing weight. Any movement is better than none and can help prevent cancer.

“Sitting just doing nothing will harm you regardless whether your body weight is normal or not,” Kucuk said. “If you’re sitting all day long, your muscles are going to disappear. Muscle is extremely important in healthy lifestyle.”

Healthcare organizations recommend that adults engage in at least 150 minutes of moderate intensity exercise weekly — about 30 minutes a day for five days a week.

Steinberg offered practical strategies: “I think having an accountability partner is always helpful. It’s hard to do things on your own.”

She suggested having someone to call while taking a walk or making a plan for intentional movement. “If you sit at your desk, make sure you have a way to move around. Little steps can make a difference.”

Health experts and scientists herald the Mediterranean diet as the gold standard for healthy eating.

“All vegetables and fruit are good. Certain vegetables and fruit have known chemicals in them that prevent cancers,” Kucuk said.

The following foods, he said, contain compounds with known cancer-preventive properties:

Expert say stress is not only detrimental to health, but may also drive some of the preventable behaviors contributing to cancer rates.

Omer Kucuk, MD at Emory University Winship Cancer Institute, researches nutrition’s role in cancer prevention and treatment. He wasn’t involved in the study, but told Healthline that stress can lead people to towards those cancer-causing behaviors.

“Some people stress and they drink, some people stress and they smoke,” he told Healthline.

Stress eating creates another vicious cycle. “When they get stressed, they eat and eat and eat. Maybe for 10 minutes, 15 minutes stress is down, but then later on they get even more stressed because they feel guilty,” Kucuk said.

He said the bottom line is learning to manage stress through healthier methods like exercise, time in nature, and positive social connections, and also by avoiding stressful people and situations.​​​​​​​​​​​​​​​​

Beyond lifestyle changes, experts note the importance of being proactive about learning personal risk based on family history and advocating for screenings.

“A lot of this prevention is personal,” Steinberg said.

Current lung cancer screening guidelines only cover people ages 50 to 80 with significant smoking history, leaving non-smokers without access even as their cancer rates rise.

Lovly advocates for broader screening eligibility and new blood tests to catch cancer earlier in non-smokers.

“You can’t control the mutations of DNA within your cells but you can control what you’re eating, learning about your family history and your risk,” Steinberg said.