A new study now shows more younger people are developing and dying from colorectal cancers.

The study, published in the Journal of the American Medical Association, found that more white Americans under 55 are dying of colorectal cancer. Doctors don't know why exactly, but they believe obesity, poor diet and lack of physical activity may play a role.

Routine screening for colorectal cancer doesn't usually start until age 50, unless there's a reason to start sooner.  

Surgeon Dr. Nicholas La Gamma, of Northwell Health, says there's no reason to panic, but insists that younger people see a doctor if they exhibit certain symptoms. 

"Indications for getting a colonoscopy would be a change in bowel habits, bleeding, pain," says La Gamma. 

According to the lead author of the study, the increase in deaths is small – 1 percent annually from 2004 to 2014.