Table 1

Case-control comparison on demographics and selected risk factors for breast cancer

Subjects with XRCC1 genotype informationSubjects with hormonal measurements
Cases (n = 1088)Controls (n = 1182)PCases (n = 190)Controls (n = 407)P
Age (mean ± SD)47.7 ± 8.047.2 ± 8.70.1556.8 ± 4.756.6 ± 5.30.61
Education
 <Elementary134 (12.3)171 (14.5)55 (28.9)139 (34.2)
 Middle & high823 (75.6)892 (75.5)103 (54.2)215 (52.8)
 >High131 (12.0)119 (10.1)0.1432 (16.8)53 (13.0)0.29
Family income (yuan)
 <10,000122 (11.2)119 (10.1)25 (13.2)50 (12.3)
 <10,001–19,990433 (39.8)484 (40.9)61 (32.1)169 (41.5)
 ≥20,000533 (50.0)579 (49.0)0.64104 (54.7)188 (46.2)0.08
Family history of breast cancer among first-degree of relatives
 No1051 (96.6)1152 (97.5)181 (95.3)391 (96.1)
 Yes37 (3.4)30 (2.5)0.239 (4.7)16 (3.9)0.65
BMIa (mean ± SD)23.5 ± 3.423.2 ± 3.40.0124.6 ± 3.724.1 ± 3.60.10
WHR (mean ± SD)0.81 ± .0060.80 ± 0.06<0.010.82 ± 0.060.82 ± 0.060.24
Age at 1st live birth26.8 ± 4.126.2 ± 3.8<0.0125.1 ± 4.924.2 ± 4.00.02
Age at menarche (mean ± SD)14.5 ± 1.614.7 ± 1.7<0.0114.7 ± 1.815.1 ± 1.90.03
Age at menopausal age (mean ± SD)b48.2 ± 4.647.6 ± 4.90.0748.9 ± 4.447.6 ± 4.90.001
Physical activities
 No875 (80.4)877 (74.2)129 (67.9)236 (58.0)
 Yes213 (19.6)305 (25.8)<0.0161 (32.1)171 (42.0)0.02
Ever smoked
 No1059 (97.3)1152 (97.5)179 (94.2)392 (96.3)
 Yes29 (2.7)30 (2.5)0.84911 (5.8)15 (3.7)0.24
Ever drank
 No1050 (96.5)1136 (96.1)183 (96.3)386 (94.8)
 Yes38 (3.5)46 (3.9)0.6157 (3.7)21 (5.2)0.43
  • a BMI, body mass index; WHR, waist:hip ratio.

  • b Among postmenopausal women.