Genetic variation in the genome-wide predicted estrogen response element-related sequences is associated with breast cancer development

Table 1 Frequency of risk factors in breast cancer patients and controls and the adjusted odds ratios in relation to breast cancer risk^a

Risk factor	Patients, % (n= 814)	Controls, % (n= 821)	aOR (95% CI)^b
Age at menarche
>14 yr	34.1	37.6	1.00 (reference)
≤ 14 yr	65.9	62.4	1.52 (1.18 to 1.96)
Menopause
No	49.6	59.5	1.00 (reference)
Yes	50.4	40.5	0.60 (0.42 to 0.84)
Family history of breast cancer in first-degree relatives
No	88.7	90.7	1.00 (reference)
Yes	11.3	9.3	1.20 (0.83 to 1.73)
Nulliparity
No	11.6	10.2	1.00 (reference)
Yes	88.4	89.8	0.67 (0.46 to 0.97)
No. of full-term pregnancies
≤ 2	51.0	45.6	1.00 (reference)
>2	49.0	54.4	0.46 (0.34 to 0.61)
Age at first full-term pregnancy
≤ 23 years	62.6	64.0	1.00 (reference)
>23 years	37.4	36.0	1.30 (1.00 to 1.69)
Body mass index
≤ 23	56.9	59.1	1.00 (reference)
>23	43.1	40.9	0.90 (0.71 to 1.15)
Use of oral contraceptives
No	81.4	82.1	1.00 (reference)
Ever	18.6	17.9	1.05 (0.78 to 1.40)

^aaOR, adjusted odds ratio; 95% CI, 95% confidence interval; ^baOR and 95% CI were estimated in a logistic regression model in which the age of study participants was included.

ISSN: 1465-542X