Prior oral contraception and postmenopausal fracture: a Women’s Health Initiative observational cohort study

Abstract

To test for the possible association of past oral contraceptive (OC) use and incident fracture after menopause. A prospective cohort of 93,725 postmenopausal women. Forty Women's Health Initiative (WHI) clinical centers across the United States. Ethnically diverse 93,725 volunteer postmenopausal women, 50 to 79 years old. None. The main outcome was self-reported incident first fracture assessed prospectively by annual questionnaire. The adjusted relative hazard (HR) for fracture among past OC users was 1.07 (95% CI, 1.01-1.15). Among women without any postmenopausal hormone treatment, past OC use for < or =5 years led to an HR of 1.15 (95% CI, 1.04-1.27) and for past OC use >5 years led to an HR of 1.09 (95% CI, 0.97-1.23) compared with never users. This study does not support the idea that past OC use protects against later fracture.