Table 2.

Potential risk factors for ovarian, colon, rectal, and breast cancers by age band at diagnosisa

<75 years old≥75 years old
CasesPerson-yearsHR (95%CI)bP or PtrendCasesPerson-yearsHR (95%CI)bP or PtrendPinteractionc
Ovarian Cancer
Age at baseline
 <6092159,8191.02143,1371.0
 60–6458119,5230.87 (0.61–1.25)4678,2981.31 (0.75–2.27)
 ≥653762,0171.20 (0.77–1.87)0.646893,4861.68 (0.98–2.88)0.0470.30
Physical activity level
 Low71159,8351.05742,9051.0
 Moderate5391,5461.27 (0.88–1.83)4488,9531.23 (0.82–1.85)
 High5883,8401.55 (1.08–2.22)0.023083,0630.97 (0.62–1.53)0.970.12
Family history of ovarian cancerd
 No173332,2441.0132209,4711.0
 Yes149,1183.16 (1.83–5.45)<0.000135,4500.93 (0.30–2.93)0.900.06
Number of live births
 02327,2551.01319,6971.0
 1–259101,8340.69 (0.42–1.13)4170,0190.91 (0.48–1.74)
 3–474138,5680.60 (0.37–0.96)5983,2501.13 (0.60–2.11)
 5+3171,7820.45 (0.25–0.79)0.0052140,4770.85 (0.41–1.74)0.980.09
Colon Cancer
Age at baseline
 <60236201,6561.010956,7551.0
 60–64228147,6801.57 (1.29–1.92)28199,4701.29 (1.02–1.64)
 ≥6514074,3512.28 (1.78–2.92)<0.0001317115,0391.26 (0.99–1.60)0.140.0002
Body mass index (BMI)
 <25198167,6471.0244106,2671.0
 25–<30235156,5831.28 (1.06–1.56)274103,7591.18 (0.99–1.41)
 ≥3017199,1571.44 (1.16–1.78)0.000618961,2371.38 (1.13–1.69)0.0010.69
Smoking
 Never370274,4861.0495191,7641.0
 Past13080,1191.27 (1.04–1.56)11547,1780.97 (0.79–119)
 Current9662,3811.27 (1.01–1.60)0.017927,9151.22 (0.96–1.56)0.220.53
Estrogen use
 Never419262,5881.0454166,1681.0
 Ever185160,7990.71 (0.60–0.85)0.0002253105,1960.88 (0.75–1.03)0.110.10
History of diabetes
 No553399,9561.0655258,9391.0
 Yes5122,8771.35 (0.99–1.84)0.065111,9281.59 (1.18–2.14)0.0020.54
Aspirin or NSAID usee
 No10060,5651.012540,4881.0
 Yes320288,1480.70 (0.56–0.89)0.003460188,0290.78 (0.64–0.95)0.020.45
Rectal Cancer
Age at baseline
 <6073202,6031.02357,5701.0
 60–6465147,8661.40 (0.97–2.01)48101,1571.11 (0.66–1.89)
 ≥654574,5752.34 (1.51–3.63)0.000261117,0371.18 (0.69–2.00)0.560.05
Smoking
 Never105275,5401.090194,8321.0
 Past3880,5601.23 (0.84–1.80)2648,0621.23 (0.80–1.91)
 Current3562,5411.68 (1.13–2.49)0.011428,4011.19 (0.67–2.11)0.360.54
Estrogen use
 Never129263,6691.087169,1101.0
 Ever54161,3750.70 (0.50–0.96)0.0345106,6541.00 (0.67–1.48)1.000.37
Oral contraceptive use
 No140332,0791.0122234,8291.0
 Yes4392,9641.27 (0.88–1.83)0.201040,9350.46 (0.23–0.91)0.030.04
Breast Cancer
Age at baseline
 <60687196,2721.020753,3191.0
 60–64613143,4141.35 (1.19–1.52)41493,5151.10 (0.92–1.32)
 ≥6529372,9461.35 (1.15–1.58)<0.0001450110,0551.07 (0.89–1.29)0.590.006
Body mass index (BMI)
 <25547163,2181.0353100,9801.0
 25–<30606152,6251.18 (1.04–1.33)44998,0291.30 (1.12–1.52)
 ≥3044096,5791.35 (1.17–1.55)<0.000126957,8801.35 (1.13–1.62)0.0010.80
Waist-hip-ratio (WHR)
 Q1 (0.335–0.777)383110,2161.024663,1631.0
 Q2 (>0.777–0.832)367104,0330.97 (0.83–1.12)25865,2480.99 (0.82–1.18)
 Q3 (>0.832–0.892)388100,7721.01 (0.87–1.18)27165,5770.99 (0.82–1.19)
 Q4 (>0.892–2.836)44895,8131.18 (1.01–1.38)0.0229061,9901.05 (0.87–1.28)0.630.26
Family history of breast cancerd
 No1,138318,7331.0732198,5141.0
 Yes45593,8991.35 (1.21–1.51)<0.000133958,3741.57 (1.37–1.79)<0.00010.09
Age at menarche
 ≤12725175,2921.0432105,0741.0
 >12855232,9070.90 (0.81–1.00)0.048631148,5021.06 (0.94–1.21)0.340.05
Age at menopause
 <50778215,2261.0463130,6771.0
 ≥50815197,4071.15 (1.04–1.27)0.008608126,2111.35 (1.19–1.53)<0.00010.04
Number of live births
 016036,2011.010725,8381.0
 1–2511125,7400.57 (0.39–0.84)38484,9030.70 (0.44–1.11)
 3–4660166,7430.58 (0.41–0.82)40998,8130.64 (0.42–0.98)
 5+26283,9480.45 (0.32–0.65)<0.000117147,3350.57 (0.37–0.88)0.0010.50
Age at first live birth
 <2028586,0401.015944,5931.0
 20–24723193,3291.12 (0.98–1.29)463112,8811.18 (0.98–1.42)
 25–2930874,5081.17 (0.99–1.39)24755,4511.18 (0.95–1.46)
 ≥3010820,3291.45 (1.14–1.83)0.0038916,6131.40 (1.06–1.85)0.030.43
 Nulliparous16036,2011.06 (0.84–1.34)10725,8381.05 (0.78–1.42)
Smoking
 Never998267,7811.0744181,8701.0
 Past31378,1531.06 (0.93–1.21)20944,3141.17 (1.00–1.38)
 Current26560,4831.25 (1.08–1.44)0.00410026,4580.99 (0.80–1.24)0.430.22
Alcohol consumption
 No832228,8281.0631149,3291.0
 Yes761183,8051.20 (1.08–1.33)0.0007440107,5590.98 (0.86–1.11)0.730.02
History of hysterectomy
 No1,088276,4581.0703174,3291.0
 Yes505136,1741.02 (0.91–1.16)0.7136882,5301.31 (1.13–1.51)0.00030.03
Aspirin or NSAID usee
 No25656,9901.015936,9321.0
 Yes1,040280,6060.82 (0.71–0.94)0.005737177,5560.94 (0.78–1.12)0.460.28
  • 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 year old vs. ≥75 year old).

  • 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.