Table 1.
Characteristic Of Enrolled Patients
| Controls(n=1215) | Cases(n=1215) | P value | |
|---|---|---|---|
| Age (Mean ±SD) | 50.76±11.73 | 50.76±11.73 | 1.00 |
| ≤40 | 222(18.3) | 222(18.3) | 1.00 |
| >40 | 993(81.7) | 993(81.7) | |
| BMI(Mean ±SD) | 22.86±3.26 | 22.69±3.88 | 0.262 |
| Age at first full-term pregnancy(Mean ±SD) | 26.17±3.60 | 26.50±3.75 | 0.053 |
| Breastfeedinga,b | |||
| No | 311(26.1) | 428(35.2) | <0.001 |
| Yes | 884(73.9) | 787(64.8) | |
| Number of pregnancies | |||
| 0 | 147(12.1) | 254(20.9) | |
| 1 | 216(17.8) | 195(16.0) | |
| ≥2 | 852(70.1) | 766(63.0) | |
| Full-term pregnancy | |||
| No | 194(16.0) | 294(24.2) | 0.002 |
| Yes | 1021(84.0) | 921(75.8) | |
| Abortion | |||
| No | 481(39.6) | 538(44.3) | 0.019 |
| Yes | 734(60.4) | 677(55.7) | |
| Family history of malignancy | |||
| Yes | 181(14.9) | 236(19.4) | 0.003 |
| No | 1034(85.1) | 979(80.6) | |
| Family history of breast cancerc | |||
| Yes | 29(2.4) | 57(4.7) | 0.002 |
| No | 1186(97.6) | 1158(95.3) | |
| History of benign breast surgery | |||
| Yes | 181(14.9) | 121(10) | <0.001 |
| No | 1034(85.1) | 1094(90) |
Notes: aThe data of breast-feeding history were missing in 23 patients in the control group; bthe data of breast-feeding time were missing in 24 patients in the control group; cFisher’s exact probability test was used for statistical analysis.