Genetic Variants in Group-Specific Component (GC) Gene Are Associated with Breast Cancer Risk among Chinese Women

Table 1

Characteristics of cases and controls.

Variables	Cases (n = 818)	Controls (n = 935)	value
	N (%)	N (%)
Age (mean ± SD, year)	54.78 ± 11.10	54.27 ± 11.30	0.337
<53	393 (48.04)	458 (48.98)	0.730^b
≥53	425 (51.96)	477 (51.02)
Age at menarche (mean ± SD, year)	15.52 ± 2.55	15.48 ± 2.73	0.762^a
Age at first live birth (mean ± SD, year)	24.60 ± 2.70	24.58 ± 2.48	0.875^a
Chest circumference (mean ± SD, cm)	90.40 ± 8.69	90.70 ± 7.90	0.451^a
Age at menopause (mean ± SD, year)	49.18 ± 4.87	49.29 ± 6.04	0.727^a
Waist circumference (mean ± SD, cm)	87.31 ± 10.98	83.07 ± 9.84	<0.001^a
Menopausal status at baseline
Premenopausal	214 (26.16)	385 (41.22)	<0.001^b
Postmenopausal	604 (73.84)	549 (58.78)
Body mass index (mean ± SD, kg/m^2)	24.93 ± 3.54	24.14 ± 3.16	<0.001^a
<18.5	19 (2.35)	15 (1.60)	<0.001^b
18.5–23.9	325 (40.17)	471 (50.37)
24.0–27.9	330 (40.79)	339 (36.26)
≥28.0	135 (16.69)	110 (11.77)
Education
Primary school	256 (31.33)	228 (24.44)	<0.001^b
Junior middle school	348 (42.60)	341 (36.55)
Senior middle school	148 (18.12)	225 (24.12)
University and above	65 (7.96)	139 (14.90)
Income (yuan)
<30000	216 (26.54)	149 (15.94)	<0.001^b
30000–49999	163 (20.02)	121 (12.94)
50000–100000	265 (32.56)	317 (33.90)
≥100000	170 (20.88)	348 (37.22)
Oral contraceptive use
No	652 (80.10)	760 (82.16)	0.299^b
Yes	162 (19.90)	165 (17.84)
Family history of breast cancer
No	711 (88.76)	873 (94.38)	<0.001^b
Yes	90 (11.24)	52 (5.62)

^aWelch’s t-test was applied for the unequal variances. ^bTwo-sided chi-square test.