Shadyab, Aladdin H.

Objective: To evaluate whether effects of oral hormone therapy (HT) on risks of venous and arterial vascular events differ by baseline statin or aspirin use. Methods: We performed time-to-event analysis using data from the Women’s Health Initiative menopausal HT randomized trials to assess risk of thrombotic events. Women were randomized to oral conjugated equine estrogens (CEEs) alone or placebo among women with prior hysterectomy (n = 10,739), and CEE with medroxyprogesterone acetate (MPA) or placebo among women with an intact uterus (n = 16,608), stratified by baseline personal use of statins and aspirin. We evaluated risk of prespecified, adjudicated thrombotic events, including coronary heart disease, stroke, venous thromboembolism, and/or composite major adverse cardiovascular events, at 2 and 5 years. Results: Baseline statin use (n = 827 in CEE-alone trial; n = 1,115 in CEE+MPA trial) or aspirin use (n = 2,212; n = 3,431) was limited. At 5-year follow-up, coronary heart disease risk for CEE-alone versus placebo was hazard ratio (HR) = 0.81 (95% CI: 0.44-1.49) in statin users, similar to nonusers, HR = 1.07 (95% CI: 0.82-1.40). For CEE+MPA, there was also no difference by statin use, HR = 1.02 (95% CI: 0.55-1.89) and HR = 1.47 (95% CI: 1.13-1.90), respectively. Neither statin nor aspirin exposure significantly modified effects of HT on any arterial or venous thrombotic outcome at 2 or 5 years. Conclusions: In this secondary randomized clinical trial analysis, neither statins nor aspirin significantly modified effects of oral HT on key arterial or venous thrombotic outcomes at 2 or 5 years. Results, however, may be underpowered given low baseline exposure prevalence for both statins and aspirin.

Abstract There are limited prospective data on whether established risk factors modify breast cancer risk in women with pathogenic variants (PV) in BRCA1/2 and virtually no risk modification data for ATM, CHEK2, or PALB2. We conducted a nested case–control study in the Women’s Health Initiative (WHI), randomly selecting women with and without breast cancer for DNA sequencing. We evaluated breast cancer odds associated with obesity, family cancer history, smoking, alcohol, parity, breastfeeding, oophorectomy, tubal ligation, neighborhood socioeconomic status, and menopausal hormone therapy (MHT) with estrogen and progestin or estrogen only in PV carriers and noncarriers. In exploratory analyses, we grouped genes by established predisposition for estrogen receptor (ER)-positive (ATM and CHEK2) or ER-negative (BRCA1 and PALB2) disease. Multivariable models with interaction terms were used to assess differential risk modification by PVs. Among 12,957 WHI participants, 287 carried PVs. Breastfeeding was modestly associated with reduced risk for PALB2 [OR = 0.08; 95% confidence interval (CI), 0.00–0.92; P value = 0.042]. With one-sided 95% CI, power was sufficient to exclude OR ≥2.0 with obesity for ATM and BRCA2; smoking and alcohol for CHEK2; no breastfeeding for ATM; no oophorectomy for BRCA2 and CHEK2; no tubal ligation for CHEK2; and neighborhood socioeconomic status for all genes. Estrogen + progestin MHT was modestly associated with increased risk for ER-positive PVs (OR = 7.31; 95% CI, 1.14–64.20; P = 0.036). PVs did not modify risk (interaction P ≥ 0.05). BRCA1/2, ATM, CHEK2, and PALB2 PV carriers do not have breast cancer OR ≥2.0 with many established risk factors. However, MHT warrants additional study in PV carriers. Significance: There is limited information on whether established risk factors increase breast cancer risk from PVs. In the WHI, PV carriers had no substantial (≥2-fold) increase with most risk factors, except potentially MHT in ATM or CHEK2 carriers. The results may inform counseling and research on MHT.