One potential explanation for the stronger association with colon cancer could be that the colon is more susceptible to the effects of insulin and insulin-like growth factor (IGF-1) than the rectum,27 which has a significant role in growth28 and cancer promotion.29 In the present study, however, the risk of colon cancer and rectal cancer for the highest versus lowest categories of height was similarly increased in both men (22% and 25%) and women (23% and 18%), although the dose-response was more evident for colon cancer than rectal cancer in both sexes. This evidence concerns the gene IGF1 and cancer.