Premenopausal Breast Cancer Risk Factors and Associations with Molecular Subtypes: A Case-Control Study

Table 2

Associations between exposure and premenopausal breast cancer.

Risk factor		Premenopausal breast cancer		COR	95% CI
		Cases ()	Controls ()
Sports activity	Yes	157 (92.4%)	160 (94.1%)	0.75	0.32-1.77	0.518
	No	13 (7.6%)	10 (5.9%)
Alcohol intake	Yes	100 (58.8%)	41 (24.1%)	4.49	2.82-7.16	<0.001
	No	70 (41.2%)	129 (75.9%)
Obesity/overweight in adolescence/early adulthood	Yes	71 (41.8%)	9 (5.3%)	12.8	6.13-26.8	<0.001
	No	99 (58.2%)	161 (94.7%)
Menstrual cycle regularity	Regular	77 (45.3%)	79 (46.5%)	0.95	0.62-1.46	0.828
	Irregular	93 (54.7%)	91 (53.5%)
Menses quantity	Normal	129 (75.9%)	154 (90.6%)	0.32	0.17-0.60	<0.001
	Heavy	41 (24.1%)	16 (9.4%)
History of primary infertility	Yes	15 (8.8%)	1 (0.6%)	16.3	2.13-125.2	0.007
	No	155 (91.2%)	169 (99.4%)
Nulliparity	Yes	152 (89.4%)	135 (79.4%)	2.18	1.18-4.04	0.012
	No	18 (10.6%)	35 (20.6%)
Contraception use	Yes	93 (54.7%)	50 (29.4%)	2.89	1.85-4.53	<0.001
	No	77 (45.3%)	120 (70.6%)
History of benign breast disease	Yes	19 (11.2%)	2 (1.2%)	10.5	2.42-46.1	0.002
	No	151 (88.8%)	168 (98.8%)
Family history of breast cancer	Yes	33 (19.4%)	23 (13.5%)	1.53	0.86-2.75	0.146
	No	137 (80.6%)	147 (86.5%)
Radiation exposure	Yes	36 (21.2%)	42 (24.7%)	0.81	0.49-1.35	0.439
	No	134 (78.8%)	128 (75.3%)

COR = crude odds ratio.