Table 1 Characteristics of the participants
Factors | Cases N = 384 n(%) | Controls N = 566 n(%) | OR1 (95% CI) | OR2 (95% CI) |
|---|---|---|---|---|
Age at interview | ||||
≤ 50 years | 138(36) | 178(31) | 1.00 | |
>50 years | 246(64) | 388(69) | 0.82(0.62–1.08) | NS |
Area of residence | ||||
rural | 189(49) | 292(52) | 1.00 | |
urban | 195(51) | 274(48) | 0.91(0.70–1.18) | NS |
Menopausal status | ||||
Pre/perimenopausal | 134(35) | 170(30) | 1.00 | |
Postmenopausal | 250(65) | 396(70) | 0.80(0.60–1.06) | NS |
Age at menopause 3 | ||||
≤ 50 years | 144(59) | 252(64) | 1.00 | |
>50 years | 102(41) | 140(36) | 1.28(0.92–1.77) | NS |
Age of menarche | ||||
≤ 12 years | 155(40) | 150(27) | 1.86(1.41–2.45) | |
>12 years | 229(60) | 412(73) | 1.00 | NS |
Use of oral contraceptives | ||||
no | 341(89) | 548(97) | 1.00 | 1.00 |
yes | 43(11) | 18(3) | 3.84(2.18–6.77) | 4.40(1.46–13.28) |
Use of HRT 3 | ||||
no | 231(92) | 393(99) | 1.00 | 1.00 |
yes | 19(8) | 3(1) | 10.78(3.15–36.81) | 7.34(2.03–26.53) |
First degree family history | ||||
no | 341(89) | 522(92) | 1.00 | |
yes | 43(11) | 44(8) | 1.5(0.96–2.33) | NS |
Age at first full pregnancy | ||||
<23 years | 106(35) | 239(50) | 1.00 | 1.00 |
≥ 23 years | 197(65) | 242(50) | 1.84(1.37–2.47) | 1.91(1.29–2.83) |
Parity | ||||
nulliparous | 79(20) | 78(14) | 1.00 | |
1–2 | 175(46) | 255(45) | 0.68(0.47–0.98) | NS |
3 plus | 130(34) | 233(41) | 0.55(0.38–0.80) | NS |
Abortion or miscarriage | ||||
no | 183(57) | 247(50) | 1.00 | 1.00 |
yes | 138(43) | 248(50) | 0.75(0.57–0.99) | 0.56(0.38–0.82) |
Lactation | ||||
no | 67(22) | 84(17) | 1.00 | |
yes | 238(78) | 404(82) | 0.74(0.52–1.06) | NS |
Medication to suppress lactation | ||||
no | 273(90) | 438(90) | 1.00 | |
yes | 31(10) | 50(10) | 0.99(0.62–1.60) | NS |
Radiation to the chest | ||||
no | 372(97) | 550(97) | 1.00 | |
yes | 12(3) | 16(3) | 1.11(0.52–2.37) | NS |
Body mass index | ||||
≤ 29 kg/m2 | 282(74) | 498(88) | 1.00 | 1.00 |
>29 kg/m2 | 97(26) | 68(12) | 2.52(1.79–3.55) | 3.13 (2.03–4.84) |
Benign breast disease | ||||
no | 315(82) | 472(83) | 1.00 | |
yes | 69(18) | 94(17) | 1.10(0.78–1.55) | NS |