It’s a mystery. The number of colorectal cancer cases is declining for people 50 and older but going up for younger people. Doctors don’t know why.

A new study is identifying younger people who might need to be screened before they’re 45.

Brian Van Bokkelen is always embracing new things. He recently learned to play the guitar. At 46, he also knows it’s time to stay in tune with his health.

“If my doctor’s telling me it’s time to start checking on these things, it’s time to start checking on them,” said Brian.

Last year, he had his first colonoscopy, and fortunately, the results were good. The recommended age for colorectal cancer screening is now 45. It was lowered due to an increase in cases in people younger than 50, what’s called early-onset colorectal cancer.

Half of early-onset colorectal cancer cases occur in people ages 45 to 49, but the other half is found in people younger than that according to Dr. Thomas Imperiale, research scientist at Regentrief and professor of medicine at the IU School of Medicine.

“So, even with these new recommendations to start screening at age 45, half of early-onset colon cancer could be missed,” explained Dr. Imperiale.

Imperiale led a study of 3,000 male veterans ages 35 to 49. His research identified several risk factors, which include being at the top of the age range in the study, no regular use of non-steroidal anti-inflammatory drugs, like Advil or Aleve, no regular use of statins, use of alcohol, family history and other comorbidities.

"If you’re 45 to 49 years old, you should be talking to your primary care provider about getting screened for colon cancer,” Dr. Imperiale further urged.

There are also symptoms doctors say you need to watch for, which include rectal bleeding, a change in bowel habits, lower abdominal pain, unintentional weight loss and anemia. If you notice any of these, see your doctor.