Aragaki, Aaron K.

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 Background Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10−8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk. Methods We conducted a GWAS in European descent CRC cases and control subjects using a discovery–replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10−8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided. Results The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10−8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0. Conclusions This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.