In their cohort study of young-onset colorectal cancer (CRC), You et al1 showed that early-onset (before age 50 years) CRC is more common in patients with nonwhite ethnicity, who lack health insurance, and who live in southwestern states. The authors state that young-onset CRC is also found most often in the left-sided colon or rectosigmoid area.1 I appreciate the important results of this very large-scale study. But, there are some issues to be considered. Sporadic CRC is very rare before age 40 years. The CRC incidence rises slowly in the late forties, with most of cases of CRC occurring after age 50 years. Colorectal cancer shows the steepest increase with advanced age.2,3 Smoking, sedentary lifestyle, and diet seem to be the major risks for nonwhite persons. For these reasons, it is not clear that it is worthwhile to perform screening CRC before age 50 years.