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Table 1 Risk factors for breast cancer derived from univariate analysis

From: Risk factors for breast cancer in Iran: a case-control study

 

Number (%)*

  

Parameter

Cases (n = 286)

Controls (n = 249)

OR (95% CI)

P

Age groups (years)

    

   = 39

87 (30.4)

101 (40.6)

1.00 (ref.)

 

   40-49

84 (29.4)

68 (27.3)

1.43 (0.93-2.20)

0.10

   50-59

57 (19.9)

44 (17.7)

1.50 (0.92-2.45)

0.10

   = 60

58 (20.3)

36 (14.5)

1.87 (1.13-3.10)

0.02

   Mean ± SD

47.5 (12.8)

44.2 (13.2)

  

   Median (range)

46.0 (24-81)

43.0 (23-80)

  

Educational level

    

   Illiterate

87 (30.4)

91 (36.5)

1.00 (ref.)

 

   Primary

113 (39.5)

100 (40.2)

1.18 (0.79-1.76)

0.41

   Secondary

60 (21.0)

42 (16.9)

1.49 (0.91-2.44)

0.11

   University

26 (9.1)

16 (6.4)

1.70 (0.85-3.38)

0.13

Marital status

    

   Married

205 (71.7)

209 (83.9)

1.00 (ref.)

 

   Widowed/divorced

56 (19.6)

34 (13.7)

1.68 (1.05-2.68)

0.03

   Never married

25 (8.7)

6 (2.4)

4.25 (1.71-10.57)

0.002

Family history of breast cancer

    

   No

267 (93.4)

243 (97.6)

1.00 (ref.)

 

   Yes

19 (6.6)

6 (2.4)

2.87 (1.13-7.30)

0.03

Age at menarche (years)

    

   = 12

72 (25.2)

62 (24.9)

1.20 (0.74-1.95)

0.47

   13

78 (27.3)

63 (25.3)

1.28 (0.79-2.1)

0.32

   14

74 (25.9)

60 (24.1)

1.27 (0.78-2.1)

0.33

   = 15

62 (21.7)

64 (25.7)

1.00 (ref.)

 

   Mean ± SD

13.4 (1.5)

13.5 (1.7)

  

   Median (range)

13.0 (9-18)

13.0 (9-19)

  

Parity

    

   Parous

249 (87.1)

235 (94.4)

1.00 (ref.)

 

   Nulliparous

37 (12.9)

14 (5.6)

2.78 (1.45-5.35)

0.002

Age at first full term pregnancy (years)

    

   <20

127 (51.0)

131 (55.7)

1.00 (ref.)

 

   20-24

71 (28.5)

72 (30.6)

1.02 (0.68-1.53)

0.93

   25-29

39 (15.7)

27 (11.5)

1.49 (0.86-2.58)

0.15

   = 30

12 (4.8)

5 (2.1)

2.47 (0.84-7.22)

0.10

   Mean ± SD

20.5 (5.2)

19.4 (4.3)

  

   Median (range)

19.0 (11-45)

19.0 (10-35)

  

Age at last full term pregnancy (years)

    

   = 29

82 (32.9)

85 (36.2)

1.00 (ref.)

 

   30-34

69 (27.7)

70 (29.8)

1.02 (0.65-1.60)

0.92

   35-39

62 (24.9)

49 (20.9)

1.31 (0.81-2.12)

0.27

   = 40

36 (14.5)

31 (13.2)

1.20 (0.68-2.12)

0.52

   Mean ± SD

32.5 (6.4)

31.6 (6.9)

  

   Median (range)

32.0 (17-49)

32.0 (15-51)

  

Menopausal status

    

   Premenopausal

186 (65.0)

180 (72.3)

1.00 (ref.)

 

   Postmenopasual

100 (35.0)

69 (27.7)

1.40 (0.97-2.03)

0.07

Age at menopause (years)

    

   <50

42 (42)

37 (53.6)

1.00 (ref.)

 

   = 50

58 (58)

32 (46.4)

1.60 (0.86-2.96)

0.14

   Mean ± SD

49.9 (4.9)

48.0 (5.2)

  

   Median (range)

50.0 (36-70)

48.0 (36-60)

  

Oral contraceptive use

    

   No

279 (97.6)

240 (96.4)

1.00 (ref.)

 

   Yes

7 (2.4)

9 (3.6)

0.67 (0.25-1.82)

0.43

  1. *Unless otherwise stated. CI, confidence interval; OR, odds ratio.