Table 2.

Potential risk factors for ovarian, colon, rectal and breast cancers by age band at diagnosis^a

	< 75 years old				≥ 75 years old				p for interactionc
	Cases	Person- years	HR (95%CI)b	p or ptrend	Cases	Person- years	HR (95%CI) b	p or ptrend
Ovarian Cancer
Age at baseline
< 60	92	159,819	1.0		21	43,137	1.0
60 – 64	58	119,523	0.87 (0.61 – 1.25)		46	78,298	1.31 (0.75 – 2.27)
≥ 65	37	62,017	1.20 (0.77 – 1.87)	0.64	68	93,486	1.68 (0.98 – 2.88)	0.047	0.30
Physical activity level
Low	71	159,835	1.0		57	42,905	1.0
Moderate	53	91,546	1.27 (0.88 – 1.83)		44	88,953	1.23 (0.82 – 1.85)
High	58	83,840	1.55 (1.08 – 2.22)	0.02	30	83,063	0.97 (0.62 – 1.53)	0.97	0.12
Family history of ovarian cancerd
No	173	332,244	1.0		132	209,471	1.0
Yes	14	9,118	3.16 (1.83 – 5.45)	<0.0001	3	5,450	0.93 (0.30 – 2.93)	0.90	0.06
Number of live births
0	23	27,255	1.0		13	19,697	1.0
1 – 2	59	101,834	0.69 (0.42 – 1.13)		41	70,019	0.91 (0.48 – 1.74)
3 – 4	74	138,568	0.60 (0.37 – 0.96)		59	83,250	1.13 (0.60 – 2.11)
5+	31	71,782	0.45 (0.25 – 0.79)	0.005	21	40,477	0.85 (0.41 – 1.74)	0.98	0.09
Colon Cancer
Age at baseline
<60	236	201,656	1.0		109	56,755	1.0
60 – 64	228	147,680	1.57 (1.29 – 1.92)		281	99,470	1.29 (1.02 – 1.64)
≥65	140	74,351	2.28 (1.78 – 2.92)	<0.0001	317	115,039	1.26 (0.99 – 1.60)	0.14	0.0002
Body mass index (BMI)
<25	198	167,647	1.0		244	106,267	1.0
25 - <30	235	156,583	1.28 (1.06 – 1.56)		274	103,759	1.18 (0.99 – 1.41)
≥30	171	99,157	1.44 (1.16 – 1.78)	0.0006	189	61,237	1.38 (1.13 – 1.69)	0.001	0.69
Smoking
Never	370	274,486	1.0		495	191,764	1.0
Past	130	80,119	1.27 (1.04 – 1.56)		115	47,178	0.97 (0.79 – 119)
Current	96	62,381	1.27 (1.01 – 1.60)	0.01	79	27,915	1.22 (0.96 – 1.56)	0.22	0.53
Estrogen use
Never	419	262,588	1.0		454	166,168	1.0
Ever	185	160,799	0.71 (0.60 – 0.85)	0.0002	253	105,196	0.88 (0.75 – 1.03)	0.11	0.10
History of diabetes
No	553	399,956	1.0		655	258,939	1.0
Yes	51	22,877	1.35 (0.99 – 1.84)	0.06	51	11,928	1.59 (1.18 – 2.14)	0.002	0.54
Aspirin or NSAID usee
No	100	60,565	1.0		125	40,488	1.0
Yes	320	288,148	0.70 (0.56 – 0.89)	0.003	460	188,029	0.78 (0.64 – 0.95)	0.02	0.45
Rectal Cancer
Age at baseline
<60	73	202,603	1.0		23	57,570	1.0
60 – 64	65	147,866	1.40 (0.97 – 2.01)		48	101,157	1.11 (0.66 – 1.89)
≥65	45	74,575	2.34 (1.51 – 3.63)	0.0002	61	117,037	1.18 (0.69 – 2.00)	0.56	0.05
Smoking
Never	105	275,540	1.0		90	194,832	1.0
Past	38	80,560	1.23 (0.84 – 1.80)		26	48,062	1.23 (0.80 – 1.91)
Current	35	62,541	1.68 (1.13 – 2.49)	0.01	14	28,401	1.19 (0.67 – 2.11)	0.36	0.54
Estrogen use
Never	129	263,669	1.0		87	169,110	1.0
Ever	54	161,375	0.70 (0.50 – 0.96)	0.03	45	106,654	1.00 (0.67 – 1.48)	1.00	0.37
Oral contraceptive use
No	140	332,079	1.0		122	234,829	1.0
Yes	43	92,964	1.27 (0.88 – 1.83)	0.20	10	40,935	0.46 (0.23 – 0.91)	0.03	0.04
Breast Cancer
Age at baseline
< 60	687	196,272	1.0		207	53,319	1.0
60 – 64	613	143,414	1.35 (1.19 – 1.52)		414	93,515	1.10 (0.92 – 1.32)
≥ 65	293	72,946	1.35 (1.15 – 1.58)	<0.0001	450	110,055	1.07 (0.89 – 1.29)	0.59	0.006
Body mass index (BMI)
< 25	547	163,218	1.0		353	100,980	1.0
25 - < 30	606	152,625	1.18 (1.04 – 1.33)		449	98,029	1.30 (1.12 – 1.52)	0.0006
≥ 30	440	96,579	1.35 (1.17 – 1.55)	<0.0001	269	57,880	1.35 (1.13 – 1.62)	0.001	0.80
Waist-hip-ratio (WHR)
Q1 (0.335 – 0.777)	383	110,216	1.0		246	63,163	1.0
Q2 (>0.777 – 0.832)	367	104,033	0.97 (0.83 – 1.12)		258	65,248	0.99 (0.82 – 1.18)
Q3 (>0.832 – 0.892)	388	100,772	1.01 (0.87 – 1.18)		271	65,577	0.99 (0.82 – 1.19)
Q4 (>0.892 – 2.836)	448	95,813	1.18 (1.01 – 1.38)	0.02	290	61,990	1.05 (0.87 – 1.28)	0.63	0.26
Family history of breast cancerd
No	1,138	318,733	1.0		732	198,514	1.0
Yes	455	93,899	1.35 (1.21 – 1.51)	<0.0001	339	58,374	1.57 (1.37 – 1.79)	<0.0001	0.09
Age at menarche
≤ 12	725	175,292	1.0		432	105,074	1.0
> 12	855	232,907	0.90 (0.81 – 1.00)	0.048	631	148,502	1.06 (0.94 – 1.21)	0.34	0.05
Age at menopause
< 50	778	215,226	1.0		463	130,677	1.0
≥ 50	815	197,407	1.15 (1.04 – 1.27)	0.008	608	126,211	1.35 (1.19 – 1.53)	<0.0001	0.04
Number of live births
0	160	36,201	1.0		107	25,838	1.0
1 – 2	511	125,740	0.57 (0.39 – 0.84)		384	84,903	0.70 (0.44 – 1.11)
3 – 4	660	166,743	0.58 (0.41 – 0.82)		409	98,813	0.64 (0.42 – 0.98)
5+	262	83,948	0.45 (0.32 – 0.65)	<0.0001	171	47,335	0.57 (0.37 – 0.88)	0.001	0.50
Age at first live birth
< 20	285	86,040	1.0		159	44,593	1.0
20 – 24	723	193,329	1.12 (0.98 – 1.29)		463	112,881	1.18 (0.98 – 1.42)
25 – 29	308	74,508	1.17 (0.99 – 1.39)		247	55,451	1.18 (0.95 – 1.46)
≥ 30	108	20,329	1.45 (1.14 – 1.83)	0.003	89	16,613	1.40 (1.06 – 1.85)	0.03	0.43
Nulliparous	160	36,201	1.06 (0.84 – 1.34)		107	25,838	1.05 (0.78 – 1.42)
Smoking
Never	998	267,781	1.0		744	181,870	1.0
Past	313	78,153	1.06 (0.93 – 1.21)		209	44,314	1.17 (1.00 – 1.38)
Current	265	60,483	1.25 (1.08 – 1.44)	0.004	100	26,458	0.99 (0.80 – 1.24)	0.43	0.22
Alcohol consumption
No	832	228,828	1.0		631	149,329	1.0
Yes	761	183,805	1.20 (1.08 – 1.33)	0.0007	440	107,559	0.98 (0.86 – 1.11)	0.73	0.02
History of hysterectomy
No	1,088	276,458	1.0		703	174,329	1.0
Yes	505	136,174	1.02 (0.91 – 1.16)	0.71	368	82,530	1.31 (1.13 – 1.51)	0.0003	0.03
Aspirin or NSAID usee
No	256	56,990	1.0		159	36,932	1.0
Yes	1,040	280,606	0.82 (0.71 – 0.94)	0.005	737	177,556	0.94 (0.78 – 1.12)	0.46	0.28

^aIncludes only risk factors where the association was significant in at least one of the risk sets. All remaining risk factors are included in the supplementary tables.

^bAdjusted for age at baseline, BMI (kg/m²), physical activity level (low, moderate, high), smoking (never, past, current), age at menarche (ovarian, breast), estrogen use (colon, rectal), WHR (breast), age at menopause (breast), number of live births (breast), age at first live births (breast) and alcohol intake (breast).

^cP values for tests whether HRs differ by the follow-up (< 75 y.o. vs ≥ 75 y.o.)

^dFamily history among first and second degree relatives.

^eAnalysis was restricted to women who were alive and responded to the follow-up 3 (1992) questionnaire.