A new study by the American Cancer Society reveals that four in 10 cancer cases and about one-half of all cancer deaths in adults age 30 and older in the United States are attributed to lifestyle choices, or modifiable risk factors.
These risk factors are considered things a person can typically control and include smoking, excess body weight, alcohol consumption, physical activity, diet, exposure to ultraviolet (UV) radiation, and certain carcinogenic infections, according to the study published in CA: A Cancer Journal for Clinicians.
Smoking Is the No. 1 Modifiable Risk Factor
Cigarette smoking topped the charts as the leading risk factor, contributing to nearly 20 percent of all cancer cases and close to 30 percent of cancer deaths. Smoking comprised 56 percent of potentially preventable cancers in men and almost 40 percent of those in women.
“Despite considerable declines in smoking prevalence during the past few decades, the number of lung cancer deaths attributable to cigarette smoking in the United States is alarming,“ Dr. Farhad Islami, lead author of the report, said in a news release. ”This finding underscores the importance of implementing comprehensive tobacco control policies in each state to promote smoking cessation, as well as heightened efforts to increase screening for early detection of lung cancer, when treatment could be more effective.”
In the study, Dr. Islami and his team used data on cancer incidence, mortality, and risk factors to estimate the number of cancer cases and deaths that could be attributed to each potentially modifiable risk factor. They went through this process for 30 cancer types and delved into the specifics of the modifiable risk factors.
For example, while investigating how a person’s diet could contribute to cancer risk, researchers looked at the amount of red meat and processed meat, the number of fruits and vegetables, and the amount of dietary fiber and calcium they consumed.
They found that next to cigarette smoke, excess body weight was the second main modifiable risk factor, contributing to 7.6 percent of potentially preventable cancers, followed by alcohol consumption at 5.4 percent, UV radiation exposure at 4.6 percent, and physical inactivity at 3.1 percent.
“Interventions to help maintain healthy body weight and diet can also substantially reduce the number of cancer cases and deaths in the country, especially given the increasing incidence of several cancer types associated with excess body weight, particularly in younger individuals,” Dr. Islami said.
Lifestyle Factors Accounted for up to 100 Percent of Certain Cancers
The types of cancers caused by modifiable risk factors varied. Lung cancer had the most cases attributable to these risk factors in both men and women, followed by skin melanoma, and colorectal cancer. For women, breast cancer, endometrial cancer, and colorectal cancer were the most attributable to modifiable risk factors. For men, urinary bladder cancer was.
Modifiable risk factors accounted for 100 percent of cases of cervical cancer and Kaposi sarcoma, a type of cancer associated with HIV. Additionally, modifiable risk factors contributed to 4.9 percent of ovarian cancer cases.
These lifestyle-based risk factors contributed to 50 percent of the cases in 19 of 30 different cancers, including:
- 92.2 percent of melanomas
- 94.2 percent of anal cancers
- 89.9 percent of larynx cancers
- 88.2 percent of lung and bronchus cancers
- 87.4 percent of pharynx cancers
- 85.6 percent of tracheal cancers
- 85.4 percent of esophagus cancers
- 83.7 percent of oral cancers
“These findings show there is a continued need to increase equitable access to preventive health care and awareness about preventive measures,” Ahmedin Jemal, a senior author of the study, said in the news release.
“Effective vaccines are available for hepatitis B virus, that causes liver cancer and HPV, which can cause several cancer types, including cervical, other anogenital, and oropharyngeal cancers. Vaccination at the recommended time can substantially reduce the risk of chronic infection, and consequently, cancers associated with these viruses. HPV vaccination uptake in the United State [sic] is suboptimal.”
