Table 1 Characteristics of breast cancer cases and controls at Imam Hossain and Shohada hospitals, Tehran (Iran) between September 2015 and February 2016

Age(year)^a

49.4 ± 10.6

47.1 ± 10.1

0.03

Menarche age(year)

13.6 ± 1.6

13.6 ± 1.6

NS

Marriage age(year)

19.4 ± 6.6

18.3 ± 5.7

NS

First pregnancy age(year)

19.6 ± 8.6

18.2 ± 7.4

0.04

BMI (kg/m²)

30.1 ± 5.7

29.1 ± 5.9

NS

WHR^a

0.9 ± 0.1

0.9 ± 0.1

NS

Physical activity (MET-h/day)

32.9 ± 5.4

32.7 ± 5.2

NS

Smoking (yes), n (%)

4 (3.0)

9 (3.4)

NS

Education (diploma and higher), n (%)

62 (46.3)

108 (40.4)

NS

Occupation (yes), n (%)

109 (81.3)

211 (79)

NS

Breastfeeding time(month)

40.9 (38.3)

47.3 (40.9)

NS

Menopausal status, n (%)

0.04

 pre-menopause

62 (46.3)

153 (57.3)

 post-menopause

72 (53.7)

114 (42.7)

Marital status: n (%)

NS

 Single

9 (6.8%)

16 (6.0%)

 Married

105 (78.9%)

206 (77.4%)

 Divorced

5 (3.8%)

13 (4.9%)

 Widowed

14 (10.5%)

31 (11.7%)

Medical history

 Breast cancer family history (YES): n (%)

11 (8.2)

12 (4.5)

NS

 Cancer family history (YES): n (%)

41 (30.6)

55 (20.7)

0.03

 Benign breast diseases history (YES): n (%)

12 (9.0)

14 (5.3)

NS

 Inflammatory disease history (YES): n (%)

15 (10.4)

35 (13.2)

NS

 Abortion history (YES): n (%)

52 (38.8)

78 (29.2)

NS

 OCP use, n (%)

67 (50.0)

149 (55.8)

NS

 Anti-inflammatory drugs (YES): n (%)

10 (7.5)

46 (17.3)

0.01

 HRT (YES): n (%)

7 (5.2)

29 (10.9)

NS

Dietary intakes

 Daily energy intake(kcal/day)

2562 ± 612

2753 ± 798

NS

 EDIH

0.25 ± 0.19

0.23 ± 0.22

NS

 EDIR

0.88 ± 0.31

0.94 ± 0.41

NS

 ELIH

1.53 ± 0.33

1.47 ± 0.31

NS

 ELIR

5.61 ± 1.77

5.96 ± 2.52

NS

 Vitamin D supplement (YES): n (%)

20(4.9)

65(24.4)

0.03

 Calcium supplement (YES): n (%)

35 (26.1)

73 (27.3)

NS

 Iron supplement (YES): n (%)

20 (14.9)

45 (16.9)

NS

 Folic acid supplement (YES): n (%)

16 (11.9)

30 (11.2)

NS

 Omega-3 supplement (YES): n (%)

8 (6.0)

31 (11.6)

NS

 Herbal drug (YES): n (%)

26 (19.4)

72 (27.1)

NS