Table 2

Odds ratios (OR) with 95% confidence intervals (CI) for breast cancer related to the use of oral contraceptives (OCs) while customer of the HSHS or before that.

OC user
Cases
Controls
Crude
Adjusted*

n
%
n
%
OR
OR
95% CI

No †
15
10
57
18
1
1

Yes
114
76
222
70
2.1
2.1
(1.1, 4.2)
Not recorded
21
14
37
12
1.9
1.6
(0.6, 4.0)
Total
150
100
316
100




*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.

Hemminki et al. BMC Women's Health 2002 2:9   doi:10.1186/1472-6874-2-9