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Table 4 Oral contraceptive use in relation to breast cancer risk, stratified by age a

From: A case–control analysis of oral contraceptive use and breast cancer subtypes in the African American Breast Cancer Epidemiology and Risk Consortium

 

Age <40

Age 40 to 49

Age ≥50

 

Controls ( n )

Cases ( n )

OR

(95% CI)

Controls ( n )

Cases ( n )

OR

(95% CI)

Controls ( n )

Cases ( n )

OR

(95% CI)

Never users

351

85

1.00

Reference

1,022

272

1.00

Reference

3,259

934

1.00

Reference

Ever users

796

239

1.33

(0.97 to 1.81)

2,057

584

1.18

(0.98 to 1.42)

2,562

782

1.15

(1.01 to 1.30)

OC recency

            

  < 5 years ago

482

130

1.55

(1.09 to 2.19)

482

149

1.60

(1.23 to 2.07)

111

35

1.50

(0.99 to 2.28)

 5 to 9 years ago

185

53

1.20

(0.77 to 1.86)

292

74

1.18

(0.86 to 1.63)

94

21

0.95

(0.57 to 1.58)

  ≥ 10 years ago

154

56

1.04

(0.67 to 1.61)

1,282

361

1.07

(0.88 to 1.31)

2,351

716

1.14

(1.00 to 1.29)

  P trend

  

0.02

  

<0.01

  

0.45

OC duration

            

  < 5 years

342

84

1.18

(0.81 to 1.70)

835

225

1.12

(0.90 to 1.40)

1,138

318

1.08

(0.92 to 1.27)

 5 to 9 years

239

79

1.40

(0.95 to 2.06)

629

160

1.06

(0.83 to 1.35)

761

242

1.20

(1.00 to 1.44)

  ≥ 10 years

215

76

1.48

(0.99 to 2.20)

593

199

1.39

(1.10 to 1.76)

660

217

1.20

(0.99 to 1.45)

  P trend

  

0.17

  

0.11

  

0.26

  1. CI, confidence interval; OC, oral contraceptive; OR, odds ratio. aORs adjusted for age, study, time period, geographic region, education, age at menarche, parity, age at first birth, lactation, first-degree family history of breast cancer, menopausal status and age at menopause, duration of female hormone use, body mass index, alcohol consumption, and pack-years of cigarette smoking. P trend does not include never users.
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Breast Cancer Research

ISSN: 1465-542X

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