Table 4.
Risk of total and age specific colorectal cancer (CRC) according to number of first degree relatives (FDRs, parents and siblings) with polyps and youngest age at polyp diagnosis. Vales are numbers (percentages) unless stated otherwise
| Family history of polyps | Cases (n=68 060) | Controls (n=333 753) | Multivariable adjusted odds ratio (95% CI)* | Multivariable+family history of CRC adjusted odds ratio (95% CI)† | P value |
|---|---|---|---|---|---|
| Any polyps | |||||
| Any FDR, youngest age at diagnosis <60 years | 1523 (2.4) | 4634 (1.5) | 1.75 (1.64 to 1.86) | 1.53 (1.44 to 1.64) | <0.001 |
| 1 FDR, youngest age at diagnosis ≥60 years | 3880 (5.9) | 13 367 (4.1) | 1.54 (1.48 to 1.61) | 1.33 (1.28 to 1.39) | <0.001 |
| 1 FDR, youngest age at diagnosis <60 years | 1340 (2.1) | 4260 (1.3) | 1.68 (1.57 to 1.80) | 1.51 (1.41 to 1.61) | <0.001 |
| ≥2 FDRs, any age | 522 (0.8) | 1233 (0.4) | 2.23 (1.99 to 2.49) | 1.64 (1.46 to 1.84) | <0.001 |
| ≥2 FDRs, youngest age at diagnosis <60 years | 183 (0.3) | 374 (0.1) | 2.51 (2.07 to 3.04) | 1.82 (1.49 to 2.22) | <0.001 |
| Advanced polyps | |||||
| Any FDR, youngest age at diagnosis <60 years | 489 (0.7) | 1241 (0.4) | 2.10 (1.88 to 2.35) | 1.73 (1.54 to 1.94) | <0.001 |
| 1 FDR, youngest age at diagnosis ≥60 years | 1660 (2.5) | 5129 (1.5) | 1.67 (1.57 to 1.77) | 1.36 (1.28 to 1.45) | <0.001 |
| 1 FDR, youngest age at diagnosis <60 years | 477 (0.7) | 1197 (0.4) | 2.14 (1.91 to 2.39) | 1.77 (1.58 to 1.99) | <0.001 |
| ≥2 FDRs, any age | 57 (0.1) | 151 (0.0) | 1.92 (1.39 to 2.65) | 1.22 (0.88 to 1.70) | 0.24 |
| ≥2 FDRs, youngest age at diagnosis <60 years | 12 (0.0) | 44 (0.0) | 1.21 (0.62 to 2.38) | 0.73 (0.36 to 1.47) | 0.38 |
Multivariable conditional logistic regression was used to account for the matching on age, sex, year of birth, and county of residence, and was further adjusted for year of birth (continuous), family size (continuous), income levels (fifths), education (≤9, 10-12 years, >12 years, missing), total number of previous clinic visits (fifths), number of previous endoscopies (0, 1, 2, ≥3), Charlson comorbidity index score (continuous), and major comorbidities (all binary, including diabetes, cardiovascular disease, non-colorectal cancer, liver disease, chronic pulmonary disease, connective tissue disease, and peptic ulcer disease).
Further adjusted for number of FDRs with a history of CRC (continuous).