Colon cancers were defined as tumours in the cecum, appendix, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending and sigmoid colon (C18.0-C18.7 as per the 10th Revision of the International Statistical Classification of Diseases, Injury and Causes of Death), and overlapping or unspecified origin tumours (C18.8 and C18.9). Rectal cancers were defined as tumours occurring at the rectosigmoid junction (C19) or rectum (C20). Anal canal cancers were excluded. Colorectal cancer is the combination of the colon and rectal cancer cases.
After exclusions (56 cases for missing matching information, 31 cases for missing laboratory 25-(OH)D data for the case-control set), a total of 1248 first incident colorectal cases (colon cancer=785; rectal cancer=463) were identified. Cases were not selected from Norway (blood samples only recently collected; few colorectal cancers diagnosed after blood donation) and the Malmö centre of Sweden. The numbers of cases for analyses of dietary vitamin D, calcium, and retinol were 772 colon and 448 rectal because of missing nutrient intake values from Greece.
After exclusions (56 cases for missing matching information, 31 cases for missing laboratory 25-(OH)D data for the case-control set), a total of 1248 first incident colorectal cases (colon cancer=785; rectal cancer=463) were identified. Cases were not selected from Norway (blood samples only recently collected; few colorectal cancers diagnosed after blood donation) and the Malmö centre of Sweden. The numbers of cases for analyses of dietary vitamin D, calcium, and retinol were 772 colon and 448 rectal because of missing nutrient intake values from Greece.
