Colorectal Cancer: Who’s Really at Risk?
Updated on April 4, 2026
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Colorectal cancer used to be known as an “old person’s disease.” A few decades ago, it was rare for anyone to be diagnosed before age 50. But the demographics of this common cancer have changed.
“We’re seeing younger adults — those under age 50 — developing colorectal cancer, and they’re developing it at an alarming rate,” says Jeffrey K. Lee, MD, MPH, a gastroenterologist at Kaiser Permanente San Francisco and research scientist at Kaiser Permanente Northern California.
The percentage of people who are diagnosed at a more advanced stage of cancer has also risen. Because advanced colorectal cancer has a lower survival rate than early-stage colorectal cancer, it’s important to understand the risks, get screened, and report any suspicious symptoms to your doctor. If you fall into one of the following groups, you may have a greater risk of colorectal cancer.
People With Obesity, Diabetes, and Related Conditions
Metabolic syndrome is an umbrella term that includes obesity and disorders related to obesity, such as type 2 diabetes, high blood pressure, high cholesterol and triglycerides, and metabolic dysfunction–associated steatotic liver disease. All of these conditions are linked to an increased risk for colorectal cancer.
“This category is thought to be the biggest factor for colon cancer risk, and especially early-onset colon cancer,” says Aasma Shaukat, MD, MPH, a gastroenterologist and director of outcomes research for the division of gastroenterology and hepatology at NYU Langone in New York.
These conditions influence cancer risk in a variety of ways. For example, obesity is associated with inflammation, which accelerates the development and growth of cancer cells. Excess sugar in the blood feeds cancer cells. High blood pressure promotes the growth of new blood vessels that help colorectal tumors grow.
“Usually individuals with metabolic syndrome also have a poor diet with a lot of ultraprocessed foods and high intake of red meat and processed meats,” Dr. Shaukat says. This can create an imbalance of gut microbes that might make it more hospitable to cancer.
Gen X and Millennials
Although the average age at diagnosis is 66, early-onset colorectal cancer (cases that develop in people younger than 50) is becoming increasingly common. Diagnoses in people under age 55 doubled from 1 in 10 in 1995 to 1 in 5 in 2019. Anyone who was born in the 1960s or later (Gen X and Millennial) is more likely to be diagnosed with colorectal cancer than someone who was born before 1960.
Why is the risk rising among younger people? “We don't have the answers quite yet. We think it's a combination of factors,” says Shaukat.
One factor is the rising rates of metabolic syndrome. An unhealthy diet and a lack of exercise contribute. “We know that in the younger adult population, the rates of diabetes and obesity are increasing,” says Dr. Lee.
Additionally, eating a typical meat and processed food–heavy Western diet changes the composition of our microbiome — the trillions of bacteria and other microorganisms living in our gut. It decreases the population of beneficial bacteria while increasing the population of harmful bacteria. This imbalance, which scientists call dysbiosis, leads to inflammation and DNA damage that can cause healthy colon cells to turn into cancer.
“The third hypothesis is that this younger generation received a lot more antibiotics when they were growing up,” Shaukat says. Taking antibiotics also alters the balance of bacteria in the gut in ways that can make cells in the colon turn cancerous, she says.
Colorectal cancer is often missed in younger people because doctors may not immediately suspect it in this age group. “Myself and many of my colleagues see far too many cases of young individuals with very advanced cancers who tell us they were having rectal bleeding and ongoing symptoms, sometimes for a year or longer, yet their physician dismissed them as hemorrhoids or nothing to worry about,” says Shaukat.
Survey results from 2017 showed that an estimated 82 percent of people who developed colon cancer before age 50 were misdiagnosed. This continues to be an issue — a more recent survey of more than 1,000 colorectal cancer patients and survivors found that 75 percent of them saw at least two doctors before diagnosis, and 20 percent saw four or more doctors before receiving a correct diagnosis.
People With Unhealthy Lifestyle Habits
Diet, a lack of exercise, and unhealthy habits like alcohol and tobacco use contribute to colorectal cancer risk:
- Unhealthy Diet The Western diet is high in red and processed meats, which contain substances that turn cells in the colon into cancer, especially when those meats are smoked or cooked at high temperatures. This diet is also low in fiber, which protects against colorectal cancer.
- Lack of Exercise Scientists don't yet know the reason why sedentary behavior is so closely linked to increased risk of colon cancer. One possible explanation is the higher rates of obesity among people who don't get enough physical activity. Another reason is that exercise helps move digested food more quickly through the colon. This reduces the amount of time that the colon is exposed to cancer-causing substances in food.
- Alcohol Consumption Drinking alcohol is linked to an increased risk for several types of cancer. Heavy drinkers face up to a 52 percent higher risk for colorectal cancer. One possible explanation for the link is that when our body breaks down alcohol, it produces the cancer-causing chemical acetaldehyde. Alcohol might also disrupt the gut microbiome in ways that promote cancer development.
- Tobacco Use Smoking tobacco increases the risk of not only getting colorectal cancer but also dying from it. “Although smoking has been on the decline in the U.S., which is obviously good, it remains one of the strongest risk factors,” Shaukat says. The more you smoke, the greater your risk. Tobacco smoke is filled with chemicals that cause DNA changes and promote cancer development.
While many cancer risk factors, such as age, can’t be changed, you can make lifestyle changes to lower your risk. Speak with your doctor or other medical professional if you need guidance while making these changes.
People With a Family History of Cancer, Polyps, or Genetic Conditions
Most people with colorectal cancer have no other family members with the disease. But up to one-third have a family history of either colorectal cancer or polyps — benign growths that can turn into cancer.
Having a first-degree relative — a parent, sibling, or child — with colorectal cancer almost doubles the risk of you getting it. If that family member was diagnosed before age 50, or if more than one relative had colorectal cancer, the risk is even higher.
About 5 percent of people with colorectal cancer have a condition such as Lynch syndrome or familial adenomatous polyposis, which are caused by inherited gene mutations. These conditions dramatically increase the risk of developing colorectal cancer, and at an earlier age.
“Individuals with those mutations should seek counseling from a genetic counselor, and should be screened at an earlier age and at a higher frequency,” says Melissa Lumish, MD, member of the Immune Oncology Program at Case Comprehensive Cancer Center in Cleveland, Ohio. Some people with these genetic conditions will need preventive surgery to remove their colon before cancer can form.
People of Black, Native American, Alaska Native, or Ashkenazi Jewish Descent
Colorectal cancer affects some communities more than others. Native American and Alaska Native people have the highest rates of this cancer in the U.S., followed by Black Americans. Worldwide, Ashkenazi Jews have one of the highest rates of colorectal cancer risk.
Black people are also more likely to get diagnosed at a late stage and die from it than people of other racial and ethnic groups.
“We don't completely know why this disparity exists,” says Dr. Lumish. The cause is likely a combination of factors — including a lack of access to health insurance, quality healthcare, and healthy food, and mistrust of the medical system. There is also some evidence that Black people may be more likely to have specific genetic mutations that cause more aggressive tumors.
People With a History of Colon Cancer, Polyps, or Inflammatory Bowel Disease
You're more likely to develop this cancer if you've had it before, even if it was successfully treated. The younger you were, the higher your odds of being diagnosed again. Just having polyps in your colon is a risk. These growths can turn into cancer, especially if they're large or they contain abnormal cells. Your doctor will likely recommend routine screenings to keep an eye out for any potential tumors.
People with inflammatory bowel diseases (IBDs) like Crohn's disease or ulcerative colitis need to be on higher alert and have more frequent colorectal cancer screenings. Inflammation from IBD can eventually cause cells in the colon to turn into cancer.
Not everyone with IBD will get this cancer, but the risk is higher — between 1.5 and 2.1 percent, compared with 1.2 percent in people without IBD. The risk goes up the longer you've lived with Crohn's disease or ulcerative colitis.
When to See a Doctor and Get Screened
Anyone at average risk for colorectal cancer should start screening at age 45 and continue until at least age 75 (or older, if your doctor determines there's a benefit). Those at higher risk should be screened sooner and more often.
“If you have a first-degree relative with colorectal cancer, you should start screening earlier than the current guideline-recommended age,” says Lee. “Get screened at age 40, or even sooner, depending on when your first-degree relative was diagnosed.” The American Gastroenterological Association recommends starting screening 10 years before the age when your first relative with colorectal cancer was diagnosed.
People who have a personal history of colorectal cancer or polyps, IBD, radiation to the belly or pelvic area, or a hereditary condition like Lynch syndrome or familial adenomatous polyposis might also need earlier and more frequent screening.
Colorectal cancer screening can involve a colonoscopy, virtual colonoscopy, sigmoidoscopy, or stool-based tests. Those at higher risk should stick to colonoscopy because it's the gold standard for diagnosing colorectal cancer, Lumish says.
No matter how often you get screened, be vigilant for symptoms and report them to your doctor. “The most important one is rectal bleeding. People often dismiss it as hemorrhoids, and it likely is, but it's still really important to have it checked out,” Shaukat says.
Common colorectal cancer symptoms are:
- A change in bowel habits, such as diarrhea, constipation, or narrower than normal stools, that lasts for more than a few days
- Unexplained abdominal pain
- Blood in the stool
- Unexplained weight loss
The Takeaway
- Metabolic syndrome, in addition to lifestyle choices such as diet, exercise, alcohol use, and smoking are some of the biggest risk factors.
- Colorectal cancer used to be a disease of older people, but rates are rising among those under age 50.
- Race and family history can also increase the risk of being diagnosed with this cancer.
- People at higher than average risk should start screening earlier than age 45, and they may need more frequent screening.
Resources We Trust
- Mayo Clinic: Colon Cancer: Symptoms and Causes
- American Cancer Society: Colorectal Cancer Risk Factors
- The University of Texas MD Anderson Cancer Center: What Are the Risk Factors for Colorectal Cancer?
- Centers for Disease Control and Prevention: Colorectal Cancer Risk Factors
- Johns Hopkins Medicine: Colon Cancer Risk Factors
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
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