"It’s important to note at this point the full implications of these findings. As Dr. Gilbert Welch, a professor of medicine at the Dartmouth Institute, explained in an interviewwith CNN, the number of actual increased cases of CRC among young people still remains relatively low. What is concerning, however, is that there are more cases among young people now than there were before, which translates to more serious stages of the cancer later on in life if these sections of the population continue to go unscreened.
In terms of accounting for this increase, the researchers were unable to provide an exact cause. In a statement to the press, though, they did note how, “it is not surprising that the timing of the obesity epidemic parallels the rise in colorectal cancers because many behaviors thought to drive weight gain, such as unhealthy dietary patterns and sedentary lifestyles, independently increase colorectal cancer risk.”
Dr. Rebecca Siegel, the lead author on this study, explained how this could be the case by citing a different study that found people from Africa who suddenly switched to an American diet showed signs of inflammation in their colons within just two weeks. "So this change can happen fairly rapidly," she said."