There is new evidence that avoiding smoking, heavy drinking and dangerously overweight people can have health benefits, which are the leading preventable causes of cancer in adults, according to a new study.
A study from the American Cancer Society released this week estimates that 40 percent of new cancer cases and 44 percent of cancer deaths in people 30 and older could be prevented if people stopped engaging in risky behaviors like smoking and drinking. Experts say the study provides new evidence for public health leaders to encourage people to adopt healthy lifestyles to reduce their risk of cancer, and more evidence that people need to take action to prevent cancer.
The American Cancer Society study looked at cancer cases and deaths that could have been prevented by behavioral and dietary changes or by vaccinations against HPV and hepatitis B. These vaccines reduce the risk of cancer-causing infections.
Behaviors that can increase cancer risk include smoking, secondhand smoke, drinking alcohol, and being overweight. Eating too much red or processed meat and eating diets low in fruits and vegetables, dietary fiber, or calcium also increase cancer risk. The study also cited cancer risk from infections such as hepatitis B, Epstein-Barr virus, HIV, human papillomavirus, and Kaposi’s sarcoma herpesvirus.
Experts not involved in the population-level study said it is an important warning for public health agencies and policymakers to implement policies that encourage healthy behaviors.
The findings present “a major opportunity for our country – and indeed for every country – to reduce cancer incidence and mortality by being more proactive in prioritizing prevention at the personal and societal level,” said Ernest Hawk, vice chair and chief of cancer prevention and population sciences at the University of Texas MD Anderson Cancer Center.
According to Hawk, the purpose of such research is not to shame people who smoke, drink or engage in other risky behaviors, but to inform and educate.
“It’s hard to change your lifestyle directly or consistently over time,” Hawk said. The goal is to help people “orient themselves toward helpful behaviors and helpful policies that can help them make that choice more easily.”
The study found that 40% of the nearly 1.8 million cancer cases in adults aged 30 and older in 2019 were due to “potentially modifiable risk factors.” It examined 30 types of cancer, and excluded non-melanoma skin cancers.
The causes of cancer that can be prevented, according to the study, are divided as follows:
∎ Smoking was the greatest risk factor, accounting for 19.3% of cases.
∎ Overweight was a risk factor in 7.6% of cases.
∎ Alcohol use was associated in 5.4% of cases.
∎ Ultraviolet radiation was the cause of 4.6% of cases.
Lung cancer had the highest number of cases linked to preventable risk factors assessed by researchers. The study found 104,410 preventable lung cancers in men and 97,250 in women. The next most common preventable cancers included 50,570 cases of cutaneous melanoma and 44,310 colorectal cancers.
“Despite significant declines in smoking prevalence over the past few decades, the number of lung cancer deaths in the United States attributable to smoking is alarming,” said Farad Islami, senior scientific director of cancer research at the American Cancer Society and lead author of the study.
Islami added that the study shows the need for tobacco control policies in every state that encourage people to quit smoking. He also mentioned the need for early detection of lung cancer.
Officials from the American Cancer Society also stressed the importance of vaccines against hepatitis B and human papillomavirus, or HPV. Hepatitis B causes liver cancer, and HPV can lead to multiple types of cancer, including cervical, anal, genital, and oral and throat cancers.
Earlier this year, the American Cancer Society predicted that the number of cancer cases in the U.S. would surpass 2 million for the first time this year. However, the report said that lower smoking rates, earlier detection and improved treatments have reduced death rates over the past three decades.