Study population

The study population included 161,808 postmenopausal women aged 50 to 79 enrolled in the Women's Health Initiative (WHI) Clinical Trial (CT) and Observational Study (OS) from October 1, 1993 to December 31, 1998. Study implementation details have been published previously ¹⁶, ¹⁷, ¹⁸. Follow‐up continued from study initiation until planned termination in March, 2005, and thereafter for participants providing reconsent. The data collection for the current analysis was updated through September 2012. Some women continue to be followed in the extension study. We excluded women from the analysis who had a prior history of lymphoma (n = 243) and for whom there was no information on statin use (n = 2) for a final analysis cohort of 161,563.