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Table 3 Odds ratios (OR) with 95% confidence intervals (CI) for breast cancer related to age at start of oral contraceptive (OC) use‡.

From: Oral contraceptive use before first birth and risk of breast cancer: a case control study

Age at start of OC use (in years)

Cases

Controls

Crude

Adjusted*

 

n

n

OR

OR

95% CI

16–19

11

36

0.6

0.5

(0.2, 1.6)

20–24

77

140

0.9

0.9

(0.5, 1.9)

≥ 25†

21

40

1

1

 

Age missing

5

6

..

..

 
  1. ‡ Women missing information about OC use or (21 cases and 37 controls) or not having used OCs while in the HSHS (15 cases and 57 controls) were excluded. *Adjusted for parity and age at delivery (no births before year of case's diagnosis, birth before 25 years, other), sports (no sports, sports, unknown), and smoking (never, ever, unknown). † Reference group.
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BMC Women's Health

ISSN: 1472-6874

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