Comment by reedf1

Actually this is the shocking part - it actually is enough to move the needle. Incidents of young people with cancer is small so a 100% increase can be driven by a small absolute number of patients. There has been an absolutely enormous increasing in high endurance sport something more like 20x (or 1900% increase) and ultramarathon/marathon runners are 7.5x more likely to get colon cancer, so this leads to a surprisingly large relative increase in colon cancer.