Colorectal cancer (CRC) is the third most common cancercancer globally and the second leading cause of cancer death in the United States1. Many lifestyle-related factors, such as alcohol use, obesity, diet, and physical activity, have been linked to an increased risk of developing colon cancer2. Despite this, public awareness of these modifiable risk factors remains low, contributing to rising incidence rates, especially among younger adults34.
Lifestyle Factors That Increase Colon Cancer Risk
Several modifiable lifestyle habits significantly influence the risk of developing colorectal cancer. Excess body weight, alcohol consumption, poor diet, and physical inactivity are among the most important factors that can be changed to reduce risk56. The World Cancer Research Fund and American Institute for Cancer Research provide convincing evidence that higher body mass index (BMI) and alcohol intake increase colorectal cancer risk, while physical activity lowers it5. Alcohol is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC), meaning it is a known human carcinogen linked to multiple cancers, including colorectal, breast, esophageal, and liver cancers57.
“We have an excellent opportunity to educate the public that alcohol, obesity, overweight, poor diet, and physical inactivity all increase the risk of colon cancer. We could prevent many colon cancer diagnoses.”
— Suneel Kamath, Cleveland Clinic4
Obesity is associated with an increased risk of colorectal cancer in both men and women, and poor diet—particularly one high in red and processed meats—raises risk further82. Cooking meats at very high temperatures can create chemicals that may increase cancer risk2. Physical inactivity and poor diet also contribute to obesity, which itself is a risk factor for several cancers such as uterine and breast cancers9. Additionally, tobacco use and type 2 diabetes mellitus have been linked to higher colorectal cancer risk2.
A national survey conducted in early 2024 with approximately 1,000 U.S. adults revealed that many people remain unaware of these connections. About half of respondents did not know that alcohol consumption increases colorectal cancer risk, and significant proportions were unaware that physical inactivity, obesity, or poor diet are risk factors36. These findings highlight the need for increased education to promote healthier lifestyle choices.
- Alcohol consumption increases colorectal cancer risk and is a known carcinogen510.
- Excess body weight and obesity raise the chance of developing and dying from colorectal cancer82.
- Physical inactivity contributes to colorectal cancer risk and obesity59.
- Diets high in red and processed meats and low in fiber increase colorectal cancer risk26.
- Smoking and type 2 diabetes mellitus are additional risk factors for colorectal cancer2.
Colon Cancer Awareness and Rising Incidence
Colorectal cancer incidence has been rising steadily among adults younger than 50 years, a trend often described as an emerging epidemic11. Since the mid-1990s, the proportion of advanced colorectal cancer cases in younger adults has nearly doubled, increasing from 11% in 1995 to 20% in 201912. This rise is concerning because screening guidelines have historically focused on older adults, leading to lower screening rates and delayed diagnosis in younger populations13.
Early symptoms of colorectal cancer can be subtle and easily mistaken for less serious conditions. Awareness of these warning signs and timely screening can save lives by catching cancer early or preventing it altogether2122.
Racial and ethnic disparities in colorectal cancer incidence and mortality are significant. Black Americans experience higher death rates from colorectal cancer, while Hispanic Americans have the fastest rising incidence rates1415. Lack of awareness about modifiable risk factors and symptoms contributes to these disparities and presents a barrier to prevention and early diagnosis10.
The US Preventive Services Task Force recently lowered the recommended age to begin colorectal cancer screening from 50 to 45 years for average-risk adults, reflecting the increasing incidence in younger populations1617. Individuals with family history, inflammatory bowel disease (IBD), or hereditary syndromes require earlier and more frequent screening1819.
- Colorectal cancer ranks third in cancer incidence in the US12.
- Early-onset colorectal cancer (diagnosed before age 50) is increasing globally11.
- Lower screening rates in younger adults contribute to delayed diagnosis13.
- Black Americans have higher colorectal cancer mortality; Hispanic Americans have rapidly rising incidence1415.
- Screening guidelines now recommend starting at age 45 for average-risk adults1617.
Colon Cancer Symptoms and Warning Signs
Early detection of colorectal cancer greatly improves treatment outcomes, yet many cases go undiagnosed until advanced stages due to lack of symptom awareness and screening2016. Common warning signs of colon cancer include changes in bowel habits such as diarrhea, constipation, or narrowing of stool that lasts more than a few days2021. Rectal bleeding or blood in the stool is another frequent symptom, which may appear as bright red blood or dark, tarry stools2021.
“There is a new epidemic of young people being identified with colon cancer. People should think about the risk factors while they're young.”
— Matthew Grossman, Atlantic Digestive Health Institute4
Other symptoms include a sensation of incomplete bowel evacuation, persistent abdominal discomfort or cramps, weakness, fatigue, and unexplained weight loss2021. Because colorectal cancer can bleed into the digestive tract, chronic blood loss may lead to anemia, sometimes detected first by blood tests21. It is important to seek medical evaluation if any of these symptoms occur.
Screening tests like colonoscopy can detect precancerous polyps before they develop into cancer and find colorectal cancer at early stages when treatment is most effective2216. Public education campaigns by government and nonprofit organizations are critical to improving awareness of symptoms and increasing screening uptake2324.
- Change in bowel habits lasting more than a few days20.
- Rectal bleeding or blood in stool20.
- Feeling that the bowel does not empty completely20.
- Persistent abdominal pain or cramps20.
- Unexplained weight loss and fatigue20.
