. 2019 Mar 14;364:l803. doi: 10.1136/bmj.l803

Table 2.

Relative risk and absolute risk (cumulative risk) of familial colorectal cancer by detailed relationship, age at diagnosis of youngest affected relative, and sex

Relationship	Relative risk by age at diagnosis of youngest affected relative						Absolute risk
	All ages		<50 years		≥50 years		All		Men		Women
	No	SIR^* (95% CI)	No	SIR^* (95% CI)	No	SIR^* (95% CI)	No	LCR, % (95% CI)	No	LCR, % (95% CI)	No	LCR, % (95% CI)
1 sibling+0 SDR	2089	1.7 (1.6 to 1.7)^†	188	2.1 (1.8 to 2.4)^†	1901	1.6 (1.5 to 1.7)^†	2049	7.0 (6.6 to 7.3)^†	1145	8.0 (7.4 to 8.6)^†	904	6.0 (5.5 to 6.5)^†
1 brother	1165	1.7 (1.6 to 1.8)^†	95	2.4 (1.9 to 2.9)^†	1070	1.7 (1.6 to 1.8)^†	1146	7.1 (6.6 to 7.6)^†	648	8.1 (7.3 to 8.9)^†	498	6.1 (5.5 to 6.8)^†
1 sister	924	1.6 (1.5 to 1.7)^†	93	1.9 (1.5 to 2.3)^†	831	1.6 (1.5 to 1.7)^†	903	6.8 (6.2 to 7.4)^†	497	7.9 (7.0 to 8.8)^†	406	5.8 (5.1 to 6.5)^†
1 half sibling+0 FDR	140	1.5 (1.3 to 1.8)^†	23	1.9 (1.2 to 2.8)^†	117	1.5 (1.2 to 1.8)^†	136	6.1 (4.7 to 7.6)^†	68	7.5 (4.9 to 10)^†	68	5.0 (3.4 to 6.5)^†
1 maternal half sibling	60	1.4 (1.1 to 1.8)^†	8	1.6 (0.7 to 3.1)	52	1.4 (1.0 to 1.8)^†	57	5.7 (3.5 to 7.9)^†	27	5.9 (2.4 to 9.2)^†	30	5.5 (2.7 to 8.2)^†
1 paternal half sibling	80	1.7 (1.3 to 2.1)^†	15	2.1 (1.2 to 3.5)^†	65	1.6 (1.2 to 2.0)^†	79	6.6 (4.6 to 8.5)^†	41	9.0 (5.1 to 13)^†	38	4.5 (2.9 to 6.2)^†
1 parent+0 SDR	5520	1.6 (1.5 to 1.6)^†	192	2.8 (2.5 to 3.3)^†	5328	1.5 (1.5 to 1.6)^†	5457	6.5 (6.3 to 6.8)^†	3021	7.4 (7.0 to 7.8)^†	2436	5.7 (5.4 to 6.1)^†
Father	2697	1.6 (1.5 to 1.6)^†	94	3.6 (2.9 to 4.4)^†	2603	1.5 (1.5 to 1.6)^†	2668	6.5 (6.1 to 6.8)^†	1455	7.1 (6.6 to 7.6)^†	1213	5.9 (5.4 to 6.4)^†
Mother	2823	1.6 (1.5 to 1.6)^†	98	2.4 (1.9 to 2.9)^†	2725	1.5 (1.5 to 1.6)^†	2789	6.6 (6.3 to 6.9)^†	1566	7.7 (7.1 to 8.2)^†	1223	5.6 (5.2 to 6.0)^†
1 grandparent+0 FDR	460	1.2 (1.1 to 1.3)^†	13	1.8 (1.0 to 3.1)	447	1.2 (1.0 to 1.3)^†	460	1.7 (0.7 to 2.6)^†	231	1.3 (0.8 to 1.9)^†	229	2.0 (0.2 to 3.7)^†
1 uncle/aunt+0 FDR	189	1.2 (1.0 to 1.3)^†	12	1.1 (0.6 to 1.9)	177	1.2 (1.0 to 1.4)^†	189	2.0 (0.2 to 3.7)^†	90	1.4 (0.7 to 2.0)^†	99	2.6 (0 to 6.0)
1 half sibling+1 FDR	41	3.5 (2.5 to 4.8)^†	16	7.0 (4.0 to 11)^†	25	2.7 (1.7 to 3.9)^†	39	11 (6.0 to 16)^†	22	15 (4.9 to 24)^†	17	7.6 (3.5 to 12)^†
1 maternal half sibling+1 FDR	15	2.7 (1.5 to 4.5)^†	3	3.0 (0.6 to 8.7)^†	12	2.7 (1.4 to 4.6)^†	15	9.3 (3.5 to 15)^†	8	12 (1.4 to 21)^†	7	6.8 (1.1 to 12)^†
1 paternal half-sibling+1 FDR	26	4.3 (2.8 to 6.2)^†	13	10 (5.4 to 17)^†	13	2.7 (1.4 to 4.6)^†	24	13 (4.4 to 21)^†	14	16 (1.4 to 29)^†	10	8.5 (2.3 to 14)^†
1 half sibling+1 sibling	8	3.4 (1.4 to 6.6)^†	0	-	8	4.3 (1.9 to 8.5)^†	6	20 (0.0 to 35)^†	3	24 (0 to 45)	3	8.7 (0 to 18)
1 half sibling+1 parent	32	3.6 (2.4 to 5.0)^†	15	9.4 (5.3 to 16)^†	17	2.3 (1.3 to 3.7)^†	32	7.7 (4.4 to 11)^†	19	9.8 (3.9 to 15)^†	13	5.8 (2.4 to 9.2)^†
1 grandparent+1 FDR	82	3.0 (2.4 to 3.7)^†	19	6.4 (3.8 to 10)^†	63	2.6 (2.0 to 3.3)^†	82	2.2 (1.4 to 3.1)^†	39	1.7 (0.8 to 2.5)^†	43	2.8 (1.3 to 4.3)^†
1 uncle/aunt+1 FDR	28	2.2 (1.4 to 3.1)^†	11	6.2 (3.1 to 11)^†	17	1.5 (0.9 to 2.4)	28	1.2 (0.6 to 1.9)^†	16	1.7 (0.4 to 3.0)^†	12	0.8 (0.3 to 1.3)^†
2 half siblings+0 FDR	6	3.5 (1.3 to 7.6)^†	1	2.9 (0.1 to 16)	5	3.6 (1.2 to 8.5)^†	6	14 (1.1 to 25)^†	4	24 (0 to 45)	2	6.1 (0 to 14)
2 siblings+0 SDR	105	2.2 (1.8 to 2.7)^†	11	1.7 (0.8 to 3.0)	94	2.3 (1.9 to 2.9)^†	104	9.1 (7.0 to 11)^†	60	10 (7.0 to 13)^†	44	8.1 (5.1 to 11)^†
1 sibling+1 parent+0 SDR	396	2.7 (2.4 to 3.0)^†	78	5.0 (3.9 to 6.2)^†	318	2.4 (2.2 to 2.7)^†	392	9.4 (8.2 to 11)^†	218	10 (8.4 to 12)^†	174	8.7 (7.1 to 10)^†

FDR=first degree relative; LCR=lifetime (0-79 years) cumulative risk; SDR=second degree relative; SIR=standardised incidence ratio.

Adjusted for sex, age, calendar periods, residential areas, and socioeconomic status; maximum age in third generation of latest available dataset was 68 years, so cumulative risks for grandparents/aunts/uncles are limited to this age.

^†

Significant risks.