Table 2.
Cases (n = 407)
|
Controls (n = 499)
|
Model 1*
|
Model 2**
|
|||||||
---|---|---|---|---|---|---|---|---|---|---|
N | % | N | % | OR | 95% CI | p b | OR | 95% CI | p b | |
Age at Menarche | ||||||||||
< 13 | 179 | 44.0 | 209 | 41.9 | 1 | 1 | ||||
13 – 14 | 157 | 38.6 | 215 | 43.1 | 0.82 | (0.59 – 1.15) | 0.82 | (0.58 – 1.18) | ||
≥ 15 | 62 | 15.2 | 67 | 13.4 | 1.08 | (0.67 – 1.73) | 0.85 | 1.10 | (0.66 – 1.82) | 0.90 |
Missing | 9 | 2.2 | 8 | 1.6 | ||||||
Continuous | 0.99 | (0.90 – 1.08) | 0.77 | 0.98 | (0.89 – 1.09) | 0.73 | ||||
Cycle Duration (Days) | ||||||||||
< 27 | 83 | 20.4 | 119 | 23.9 | 1 | 1 | ||||
27 – 28 | 234 | 57.5 | 292 | 58.5 | 1.07 | (0.73 – 1.56) | 1.25 | (0.83 – 1.89) | ||
≥ 29 | 79 | 19.4 | 78 | 15.6 | 1.38 | (0.85 – 2.24) | 0.20 | 1.53 | (0.91 – 2.56) | 0.10 |
Missing | 11 | 2.7 | 10 | 2.0 | ||||||
Continuous | 1.04 | (0.99 – 1.09) | 0.14 | 1.05 | (1.00 – 1.10) | 0.08 | ||||
Parity (Number of Livebirths) | ||||||||||
0 | 78 | 19.2 | 88 | 17.6 | 1 | 1 | ||||
1 | 112 | 27.5 | 117 | 23.5 | 1.29 | (0.80 – 2.06) | 1.33 | (0.78 – 2.29) | ||
2 | 148 | 36.4 | 205 | 41.1 | 1.28 | (0.82 – 1.99) | 1.33 | (0.79 – 2.22) | ||
≥3 | 69 | 17.0 | 89 | 17.8 | 1.07 | (0.64 – 1.80) | 0.74 | 1.23 | (0.67 – 2.24) | 0.57 |
Continuous | 1.03 | (0.91 – 1.18) | 0.63 | 1.07 | (0.92 – 1.24) | 0.40 | ||||
Age at 1st Livebirth | ||||||||||
< 22 | 67 | 20.4 | 52 | 12.7 | 1 | 1 | ||||
22 – 25 | 103 | 31.3 | 122 | 29.7 | 0.92 | (0.54 – 1.56) | 0.95 | (0.54 – 1.65) | ||
26 – 30 | 116 | 35.3 | 165 | 40.2 | 0.77 | (0.46 – 1.29) | 0.73 | (0.42 – 1.27) | ||
≥ 31 | 41 | 12.5 | 70 | 17.0 | 0.57 | (0.31 – 1.06) | 0.05 | 0.52 | (0.26 – 1.01) | 0.03 |
Missing | 2 | 0.6 | 2 | 0.5 | ||||||
Continuous | 0.95 | (0.92 – 0.99) | 0.01 | 0.95 | (0.91 – 0.99) | 0.01 | ||||
Breastfeeding | ||||||||||
Never | 78 | 23.7 | 94 | 22.9 | 1 | 1 | ||||
Ever | 248 | 75.4 | 316 | 76.9 | 1.00 | (0.67 – 1.50) | 0.99 | 0.98 | (0.64 – 1.49) | 0.92 |
Missing | 3 | 0.9 | 1 | 0.2 | ||||||
Menopause Status | ||||||||||
Premenopausal | 38 | 9.3 | 64 | 12.8 | 1 | 1 | ||||
Natural Menopausal | 285 | 70.0 | 336 | 67.3 | 2.06 | (0.84 – 5.08) | 0.12 | 2.50 | (0.97 – 6.45) | 0.06 |
Induced Menopausal | 83 | 20.4 | 98 | 19.6 | 2.58 | (1.02 – 6.56) | 0.05 | 2.87 | (1.08 – 7.66) | 0.04 |
Missing | 1 | 0.3 | 1 | 0.2 | ||||||
Age at Menopause | ||||||||||
< 46 | 95 | 25.8 | 78 | 18.0 | 1 | 1 | ||||
46 – 50 | 124 | 33.6 | 144 | 33.2 | 0.65 | (0.41 – 1.02) | 0.70 | (0.43 – 1.14) | ||
≥ 51 | 90 | 24.4 | 168 | 38.7 | 0.49 | (0.31 – 0.79) | 0.003 | 0.51 | (0.31 – 0.84) | 0.01 |
Missing | 60 | 16.3 | 44 | 10.1 | ||||||
Continuous | 0.96 | (0.93 – 0.99) | 0.003 | 0.96 | (0.93 – 0.99) | 0.01 | ||||
Ovariectomy | ||||||||||
No | 363 | 89.2 | 442 | 88.6 | 1 | 1 | ||||
Yes | 44 | 10.8 | 57 | 11.4 | 1.08 | (0.67 – 1.74) | 0.76 | 1.03 | (0.62 – 1.71) | 0.91 |
Reproductive Duration | ||||||||||
< 33 | 107 | 26.3 | 102 | 20.4 | 1 | 1 | ||||
33 – 36 | 98 | 24.1 | 106 | 21.2 | 0.77 | (0.48 – 1.24) | 0.84 | (0.51 – 1.40) | ||
37 – 40 | 98 | 24.1 | 158 | 31.7 | 0.67 | (0.43 – 1.06) | 0.76 | (0.47 – 1.25) | ||
≥ 41 | 41 | 10.1 | 84 | 16.8 | 0.44 | (0.25 – 0.79) | 0.01 | 0.46 | (0.25 – 0.85) | 0.02 |
Missing | 63 | 15.5 | 49 | 9.8 | ||||||
Continuous | 0.96 | (0.93 – 0.98) | 0.002 | 0.96 | (0.93 – 0.99) | 0.01 | ||||
Menopause Duration | ||||||||||
< 10 | 65 | 17.6 | 105 | 24.2 | 1 | 1 | ||||
10 – 17 | 77 | 20.9 | 103 | 23.7 | 1.50 | (0.75 – 3.02) | 1.42 | (0.67 – 3.03) | ||
18 – 24 | 68 | 18.4 | 92 | 21.2 | 1.90 | (0.84 – 4.29) | 1.80 | (0.75 – 4.32) | ||
≥ 25 | 99 | 26.8 | 90 | 20.7 | 3.74 | (1.56 – 8.97) | 0.002 | 3.69 | (1.43 – 9.48) | 0.003 |
Missing | 60 | 16.3 | 44 | 10.1 | ||||||
Continuous | 1.05 | (1.02 – 1.08) | 0.001 | 1.06 | (1.02 – 1.09) | 0.001 | ||||
HRT c | ||||||||||
Never | 305 | 82.7 | 322 | 74.2 | 1 | 1 | ||||
Ever | 63 | 17.1 | 112 | 25.8 | 0.63 | (0.42 – 0.95) | 0.03 | 0.61 | (0.39 – 0.95) | 0.03 |
Missing | 1 | 0.3 | 0 | - | ||||||
HRT Duration c | ||||||||||
Never Users | 305 | 74.9 | 322 | 64.5 | 1 | 1 | ||||
< 4 | 32 | 7.9 | 58 | 11.6 | 0.58 | (0.34 – 0.99) | 0.53 | (0.29 – 0.94) | ||
≥ 4 | 29 | 7.1 | 51 | 10.2 | 0.70 | (0.39 – 1.24) | 0.07 | 0.75 | (0.40 – 1.37) | 0.11 |
Missing | 41 | 10.1 | 68 | 13.6 | ||||||
Continuous | 0.97 | (0.92 – 1.02) | 0.24 | 0.97 | (0.92 – 1.03) | 0.33 | ||||
OC | ||||||||||
Never | 306 | 75.2 | 367 | 73.6 | 1 | 1 | ||||
Ever | 101 | 24.8 | 132 | 26.5 | 0.67 | (0.45 – 1.00) | 0.05 | 0.60 | (0.39 – 0.93) | 0.02 |
OC Duration | ||||||||||
Never Users | 306 | 75.2 | 367 | 73.6 | 1 | 1 | ||||
< 2 | 41 | 10.1 | 61 | 12.2 | 0.57 | (0.33 – 0.96) | 0.49 | (0.28 – 0.87) | ||
≥ 2 | 49 | 12.0 | 61 | 12.2 | 0.72 | (0.43 – 1.22) | 0.10 | 0.71 | (0.41 – 1.26) | 0.09 |
Missing | 11 | 2.7 | 10 | 2.0 | ||||||
Continuous | 0.98 | (0.92 – 1.03) | 0.39 | 0.98 | (0.93 – 1.04) | 0.54 | ||||
HRT/OC Combined | ||||||||||
HRT Never/OC Never | 253 | 62.2 | 259 | 51.9 | 1 | 1 | ||||
HRT Ever/OC Never | 42 | 10.3 | 82 | 16.4 | 0.49 | (0.30 – 0.80) | 0.004 | 0.45 | (0.26 – 0.76) | 0.003 |
HRT Never/OC Ever | 52 | 12.8 | 63 | 12.6 | 0.44 | (0.26 – 0.75) | 0.002 | 0.38 | (0.21 – 0.67) | 0.001 |
HRT Ever/OC Ever | 21 | 5.2 | 30 | 6.0 | 0.60 | (0.29 – 1.26) | 0.18 | 0.59 | (0.27 – 1.31) | 0.20 |
Missing | 39 | 9.6 | 65 | 13.0 |
Percentages may not add to 100.0 because of rounding.
For ordinal variables, test for trend was performed.
In menopausal women only.
HRT = Hormone Replacement Therapy.
OC = Oral Contraceptives.
Model 1: adjusted for area, age at study, smoking (ever/never, pack-years, time since quitting).
Model 2: adjusted for area, age at study, smoking (ever/never, pack-years, time since quitting), ETS, education, BMI.