Table 2.
Association between family history of polyps in first degree relatives (FDRs, parents and siblings) and risk of colorectal cancer (CRC). Values are numbers (percentages) unless stated otherwise
| Polyp types in FDRs | Cases (n=68 060) | Controls (n=333 753) | Age adjusted odds ratio (95% CI)* | Multivariable adjusted odds ratio (95% CI)† | Multivariable+family history of CRC adjusted odds ratio (95% CI)‡ |
|---|---|---|---|---|---|
| No polyps | 62 318 (91.6) | 314 893 (94.3) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) |
| Any polyp | 5742 (8.4) | 18 860 (5.7) | 1.55 (1.50 to 1.60) | 1.62 (1.57 to 1.68) | 1.40 (1.35 to 1.45) |
| Advanced polyps | 2194 (3.2) | 6477 (1.9) | 1.68 (1.60 to 1.77) | 1.76 (1.67 to 1.86) | 1.44 (1.36 to 1.51) |
| Serrated polyps: | |||||
| Hyperplastic | 1667 (2.4) | 6114 (1.8) | 1.34 (1.27 to 1.42) | 1.38 (1.30 to 1.46) | 1.23 (1.16 to 1.31) |
| Sessile serrated | 123 (0.2) | 437 (0.1) | 1.37 (1.12 to 1.67) | 1.43 (1.16 to 1.77) | 1.27 (1.03 to 1.57) |
| Conventional adenomas: | |||||
| Tubular | 2458 (3.6) | 7783 (2.3) | 1.57 (1.50 to 1.64) | 1.62 (1.54 to 1.70) | 1.39 (1.32 to 1.46) |
| Tubulovillous | 1856 (2.7) | 5437 (1.6) | 1.69 (1.60 to 1.79) | 1.77 (1.67 to 1.87) | 1.44 (1.36 to 1.53) |
| Villous | 252 (0.4) | 697 (0.2) | 1.77 (1.54 to 2.05) | 1.82 (1.57 to 2.12) | 1.40 (1.20 to 1.63) |
Conditional logistic regression was used to account for matching on age, sex, year of birth, and county of residence.
Multivariable model was further adjusted for year of birth (continuous), family size (continuous), income levels (fifths), education (≤9 years, 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 family history of CRC in FDRs.