Study: Lifestyle changes may prevent nearly half of the world’s cancer deaths

Smoking and alcohol use contribute to many cases of cancer.
A recent comprehensive global study investigated cancer cases that were attributable to modifiable risk factors. It found that nearly half of cancer deaths worldwide, 44.4 percent, may have been avoidable if the victims had paid attention to factors that raised cancer risk and made lifestyle changes to reduce those risks.

Some choices are no-brainers: If you’re allergic to peanuts, don’t eat peanut butter; if you need a good night’s sleep, don’t drink coffee before bedtime; if you don’t want to sunburn at the beach, put on some sunscreen first.

Still, many people are a lot less careful when it comes to preventing cancer, which is second only to heart disease as the leading cause of death worldwide.

A recent comprehensive global study investigated cancer cases that were attributable to modifiable risk factors. It found that nearly half of cancer deaths worldwide, 44.4 percent, may have been avoidable if the victims had paid attention to factors that raised cancer risk and made lifestyle changes to reduce those risks.

The study, published in The Lancet in August, says worldwide preventable cancer deaths rose to 4.45 million in 2019, a 20.4 percent increase from 2010. The risk factors topping the list: tobacco use, drinking alcohol, and being obese or overweight.

Men with cancer were significantly more likely to die from a preventable cancer than women. The study says 50.6 percent of the male cancer deaths were attributable to preventable risk factors, compared with 36.3 percent of the female deaths.

“The critically important point to be made is that there are a very large number of cancers that might be prevented if action is taken to eliminate or substantially reduce exposure to toxic agents, and modify personal behaviors that increase cancer risk,” says Maurie Markman, MD, President of Medicine and Science at Cancer Treatment Centers of America® (CTCA).

The study in the Lancet, funded by the Bill and Melinda Gates Foundation, used the Global Burden of Disease Study 2019 to analyze how many cancer deaths were due to preventable risk factors. It also calculated the disability-adjusted life-years (DALYs) of those preventable cancers, which covers both the reduced years of living following a cancer diagnosis and the years of living with a disabling disease. The study covered 23 types of cancer and 34 risk factors.

In this article we’ll explore:

If you’re at high risk for cancer and are interested in learning more about screening for lung, breast or colorectal cancer at CTCA, call us or chat online with a member of our team.

Types of preventable cancer risk factors

The cancer study broke down the known risk factors into three categories:



Environmental and occupational

  • Being exposed to air pollution
  • Being exposed to asbestos

Risky behaviors are the most significant preventable factors contributing to global cancer, but metabolic risk factors saw the greatest increase between 2010 and 2019.

During that time, cancer deaths attributable to:

  • Metabolic risk factors increased 34.7 percent
  • Behavioral risk factors increased 17.9 percent
  • Environmental or occupational factors increased 16.7 percent

The new study shows that cancer deaths and risk-attributable cancer deaths are happening with greater frequency in the United States and other more economically advanced countries. Those countries account for more than a quarter of the deaths in the two categories, but only represent 13.1 percent of the world population.

“It is recognized that modifying habits that increase cancer risk, including smoking and overeating, is very difficult,” Dr. Markman says. “This is why it is better to encourage good habits at a young age, including never smoking and preventing the development of obesity.”

Cancer survivors need to be aware of risk factors as well, because they have the potential of getting a second cancer unrelated to their first.

Leading preventable cancer deaths by type

The study says the leading risk-attributable cancers deaths in 2019 by type of cancer were:

It is difficult to overstate the critical importance of cancer prevention, both for individuals and society,” Dr. Markman says. “By preventing cancer, an individual will not have to experience the symptoms of the disease, the risk of death, the side effects associated with any anti-treatment program, and the costs of the malignant condition and its therapy.”

Preventable factors that may reduce cancer risk

There may be other preventable risk factors that researchers haven’t uncovered yet that may play an additional role in reducing cancer in the future.

Here is a look at the ones from the new study.

Tobacco use

Despite decades of anti-smoking campaigns, smoking and other forms of tobacco use were responsible for 36.9 percent of preventable cancer deaths, the study said. Tobacco smoke contains dozens of carcinogens and has been linked to several cancers, including lung cancer and head and neck cancers.

One way to reduce cancer deaths and other negative health outcomes is for active smokers to quit smoking. Breaking the habit isn’t easy because smoking may be a means of self-medicating for many, helping them to focus, stay alert or cope with stress or anxiety. Taking part in a smoking cessation program may help, especially if it addresses the root causes of stress and anxiety and looks for healthier solutions to other concerns.

Non-smokers should remember that second-hand smoke is also a cancer risk and they should avoid situations where second-hand smoke is present.

Alcohol use

An American Cancer Society study says that drinking alcohol was linked to more than 75,000 new cancer diagnoses and 19,000 cancer deaths in the U.S. each year from 2013 to 2016. The study in the Lancet says that alcohol use accounted for 4.9 percent of cancer deaths in 2019, and it says the Global Cancer Observatory showed alcohol responsible for 4.1 percent of new cancer cases in 2020.

Although there is no safe level of drinking, doctors have focused on warning against excessive drinking. The risk of cancer increases the more alcohol a person drinks at any one time (binge drinking), and also by how much a person drinks over time.

Excessive drinking has been connected to oral cancer, throat cancer, esophageal cancer, liver cancer, colorectal cancer and breast cancer.

The standard recommendation is no more than two drinks a day for men and only a single drink a day for women. The recommendation is based on a drink being 12 ounces of beer at 5 percent alcohol by volume (ABV), 5 ounces of wine at 12 percent ABV, or a 1.5-ounce shot of 80-proof distilled liquor. The higher the ABV, the fewer the ounces that should be consumed.

Obesity or being overweight (high BMI)

Obesity may be a factor in as many as 10 percent of new cancer cases each year, in part because it produces hormones and growth factors that may promote tumor growth. Also, fat cells sometimes excrete chemicals that damage DNA, which may lead to cancer cells forming. Being overweight increases the risk factors for breast cancer, colorectal cancer, pancreatic cancer and other cancers.

The new study attributed 4.9 percent of cancer deaths in 2019 to high BMI. While the risk factor is metabolic, it is often driven by behavioral decisions people make. Reversing weight gain isn’t easy, but people who are obese or overweight may achieve significant and sustained weight loss through a combination of diet, physical activity and stress management.

Poor diets

Healthy diets can keep us physically fit and help stave off cancer.

A healthy diet should have ample amounts of vegetables and fruits. Cruciferous vegetables, such as broccoli and cauliflower, come packed with natural ingredients that may help fight cancer. A healthy diet may include leaner meats, such as chicken, as well as fish, which provides sources of healthy proteins rich in amino acids.

A Mediterranean diet is often recommended to help reduce risk factors for cancer. These diets avoid or limit the consumption of red meat, refined grains, sugars and alcohol. Instead, they call for vegetables of various colors, fruits, nuts, herbs, whole grains and beans. They also allow for moderate amounts of fish and seafood, poultry, dairy and eggs.

Cancer may be prevented by eating better and making other lifestyle canges.

High blood sugar (hyperglycemia)

Another risk factor is high blood sugar, as elevated fasting glucose levels have been connected to increased risk of pancreatic cancer, malignant melanoma, endometrial cancer, and urinary tract cancers. Among the risks it poses, hyperglycemia may damage DNA, impede DNA repair and dysregulate tumor suppressors. Its link to cancer has been shown even in cases where obesity is not present.

Regular exercise and a proper diet may help reduce blood sugar levels. For diabetics, maintaining proper insulin levels is also critical. Not smoking, limiting alcohol consumption and maintaining a healthy body weight are all ways of helping to achieve lower blood sugar levels.

Unsafe sex

The study found unsafe sex adding to cancer cases, particularly in women in developing countries, increasing their risk for gynecologic cancers.

The limits of cancer risk prevention

While the study in The Lancet says cancer deaths may be reduced significantly if people adhere to risk prevention guidelines, it also acknowledges that more than half of cancer cases are not connected to modifiable risk factors.

Cancers remain fundamentally linked to genetics and ageing, and although addressing contributing risk factors is crucial for cancer prevention, this will never eliminate cancer burden,” the study says. “As a result, countries should continue to invest in comprehensive cancer control strategies beyond risk factor reduction, which include health-care systems capable of early diagnosis, detection through screening for select cancers, and effective treatment options for those diagnosed with cancer.”

If you’re at high risk for cancer and are interested in learning more about screening for lung, breast or colorectal cancer at CTCA, call us or chat online with a member of our team.