Results of the Italian multicentre study: observed versus expected incidence of colorectal cancer. Total number of study subjects 1693
| Sex | Person/years of follow up | Observed cancers | Expected cancers | Incidence ratio and 95% CI |
| Males | 8985 | 4 | 12.9 | 0.31 (0.20–0.69); p<0.05 |
| Females | 5226 | 2 | 4.9 | 0.41 (0.22–4.00); NS |
| Total (M and F) | 14211 | 6 | 17.7 | 0.34 (0.23–0.63); p<0.01 |