MicroRNA Expression Changes in Women with Breast Cancer Stratified by DNA Repair Capacity Levels

Table 1

Description of the study group including DNA repair capacity levels and selected breast cancer risk factors in cases and controls.

Epidemiological characteristics	Controls	BC cases	p-value
	n=29 (%)	n=27 (%)
DRC
Low (<3.8%)	15 (26.8)	18 (32.1)	0.2561
High (≥3.8%)	14 (25.0)	9 (16.1)
Age
21-40	7 (12.5)	0 (0.0)	0.0239
41-60	11 (19.6)	14 (25.0)
61+	11 (19.6)	13 (23.2)
BMI
<25 kg/m^2	14 (25.0)	9 (16.1)	0.2772
≥25 kg/m^2	14 (25.0)	18 (32.1)
Missing	1 (1.8)	0 (0.0)
Ever been pregnant
Yes	26 (46.4)	24 (42.9)	0.9262
No	3 (5.4)	3 (5.4)
Age at first birth
≤19	6 (10.7)	4 (7.1)	0.6075
20-29	14 (25.0)	16 (28.6)
≥30	6 (10.7)	2 (3.6)
Missing	0 (0.0)	2 (3.6)
Parity
Nulliparous	3 (5.4)	3 (5.4)	0.2244
1-2 children	15 (26.8)	8 (14.3)
≥3 children	11 (19.6)	16 (28.6)
Ever breastfeed
Yes	15 (26.8)	11 (19.6)	0.4102
No	14 (25.0)	16 (28.6)
Length of breastfeeding
Never	14 (25.0)	11 (19.6)	0.0585
1-5 months	13 (23.2)	11 (19.6)
≥6 months	2 (3.6)	0 (0.0)
Missing	0 (0.0)	5 (8.9)
Oral contraceptive use
Yes	13 (23.2)	8 (14.3)	0.2405
No	16 (28.6)	19 (33.9)
Age started oral contraceptive
<20	2 (3.6)	1 (1.8)	1
≥21	11 (19.6)	7 (12.5)
Regular menstrual periods
Yes	15 (26.8)	19 (33.9)	0.1534
No	14 (25.0)	8 (14.3)
Age Menarche
≤12	0 (0.0)	11 (19.6)	0.0001
≥13	26 (46.4)	14 (25.0)
Missing	3 (5.4)	2 (3.6)
History of endometriosis
Yes	3 (5.4)	1 (1.8)	0.3349
No	26 (46.4)	26 (46.4)
Hysterectomy
Yes	9 (16.1)	6 (10.7)	0.4568
No	20 (35.7)	21 (37.5)
Age of hysterectomy
≤40	6 (10.7)	1 (1.8)	0.1264
41-49	1 (1.8)	3 (5.4)
≥50	2 (3.6)	2 (3.6)
Oophorectomy
Yes	8 (14.3)	6 (10.7)	0.5589
No	20 (35.7)	21 (37.5)
Missing	1 (1.8)	0 (0.0)
Age of oophorectomy
≤40	4 (7.1)	2 (3.6)	0.1264
41-49	2 (3.6)	2 (3.6)
≥50	2 (3.6)	2 (3.6)
Menopause (actually)
Yes	4 (7.1)	3 (5.4)	0.7664
No	23 (41.1)	22 (39.3)
Missing	2 (3.6)	2 (3.6)
Hormone replacement therapy
Yes	14 (25.0)	6 (10.7)	0.0420
No	15 (26.8)	21 (37.5)
Smoking
Yes	1 (1.8)	3 (5.4)	0.2659
No	28 (50.0)	24 (39.3)
Alcohol consumption
Yes	5 (8.9)	5 (8.9)	0.9008
No	24 (42.9)	22 (39.3)
Family history of cancer (not BC)
Yes	13 (23.2)	13 (23.3)	0.8034
No	16 (28.6)	14 (25.0)
BC history in any family member
Yes	16 (28.6)	12 (21.4)	0.4224
No	13 (23.2)	15 (26.8)

Pearson’s chi-square test was performed to assess significance among groups.
DRC: DNA repair capacity, BMI: body mass index, BC: breast cancer.