Appendix Table 1.

Hazard Ratios and 95% Confidence Intervals for the Association Between Pancreatic Cancer Risk and Duration of High-dose Oral Contraceptive Use in the California Teachers Study, 1995–2009

Duration and Timing of High-dose OC Use	No. of Cases	Person-years	Multivariable HRa	95% CI
Never used OCs	156	437,932	1	Referent
Stopped using OCs before 1974
Used for <1 year	17	69,551	1.27	0.75, 2.13
Used for 1 to <5 years	32	174,803	1.08	0.71, 1.65
Used for 5 to <10 years	24	85,213	1.40	0.88, 2.22
Used for ≥10 years	9	14,745	2.08	1.05, 4.12
P for trend			0.026
Started using OCs after 1975	4	225,928	0.86	0.25, 2.95

Abbreviations: CI, confidence interval; HR, hazard ratio; OC, oral contraceptive.

^a All models were stratified by age at baseline (in single years) and adjusted for race/ethnicity (non-Hispanic white, black, or other), body mass index, measured as weight in kilograms divided by height in meters squared (<25, 25 to <30, ≥30, or unknown), menopausal status (premenopausal, postmenopausal, or unknown), hormone therapy use (never, estrogen-only therapy, estrogen-plus-progestin therapy, both estrogen-only therapy and estrogen-plus-progestin therapy, progestin-only therapy, or unknown), age at menarche (≤11, 12, 13, or ≥14 years or unknown), total number of full-term pregnancies (nulligravid, gravid nulliparous, 1–2 full-term pregnancies, ≥3 full-term pregnancies, or unknown), smoking status (never, former, current, or unknown), and history of diabetes (no or yes).