Table 1.
Relative and absolute risk of developing colorectal cancer according to family history
| Family history | Relative risk of CRC | Absolute risk of CRC by age 79 |
| No family history | 1 | 5%1 |
| One first degree relative with CRC | 2.25 (95%CI: 2.00-2.53) | 11%2 |
| More than one first degree relative with CRC | 4.25 (95%CI: 3.01-6.08) | 21%2 |
| One first degree relative diagnosed with CRC before age 45 | 3.87 (95%CI: 2.40-6.22) | 19%2 |
1
Data from the American Cancer Society, August 2013;
2
The absolute risk of colorectal cancer (CRC) was calculated using the relative risk and the absolute risk by the age 79.