This study aims to present methods and baseline data from the Early versus Late Intervention Trial with Estradiol (ELITE), the only clinical trial designed to specifically test the timing hypothesis of postmenopausal hormone therapy (HT). The timing hypothesis posits that HT effects depend on the temporal initiation of HT relative to time since menopause.
ELITE is a randomized, double-blind, placebo-controlled trial with a 2 × 2 factorial design. Six hundred forty-three healthy postmenopausal women without cardiovascular disease were randomized to oral estradiol or placebo for up to 6 to 7 years according to time since menopause (<6 or ≥10 y). Carotid artery intima-media thickness (CIMT) and cardiac computed tomography were conducted to determine HT effects on subclinical atherosclerosis across menopause strata.
Participants in the early and late postmenopausal strata were well-separated by mean age (55.4 vs 65.4 y) and median time since menopause (3.5 vs 14.3 y). Expected risk factors (age, blood pressure, and body mass index) were associated with CIMT at baseline in both strata. In the early postmenopausal group, but not in the late postmenopausal group, we observed significant associations between CIMT and factors that may play a role in the responsiveness of atherosclerosis progression according to timing of HT initiation. These include low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, sex hormone–binding globulin, and serum total estradiol.
The ELITE randomized controlled trial is timely and unique. Baseline data indicate that ELITE is well-positioned to test the HT timing hypothesis in relation to atherosclerosis progression and coronary artery disease.
From the 1Atherosclerosis Research Unit, Keck School of Medicine, University of Southern California, Los Angeles, CA; 2Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA; 3Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA; 4Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, CA; 5Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA; 6Los Angeles Biomedical Research Institute at Harbor–University of California at Los Angeles Medical Center, Torrance, CA; and 7Departments of Health Research and Policy (Epidemiology) and Neurology and Neurological Sciences, Stanford University, Stanford, CA.
Received June 3, 2014; revised and accepted August 14, 2014.
Funding/support: This study was supported by National Institutes of Health grants R01-AG024154-01-05, R01-AG024154-06-08, and R01-AG024154-S2 from the National Institute on Aging. Teva Pharmaceuticals, Watson Laboratories Inc, and Abbott Laboratories provided the hormone products gratis.
Clinical trial registration: NCT00114517 (www.clinicaltrials.gov).
Financial disclosure/conflicts of interest: F.Z.S. serves on the advisory board for Merck and Company and Agile Therapeutics. He declares no conflicts of interest. M.J.B. has received grant support from General Electric. He declares no conflicts of interest. The remaining authors have no disclosures.
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Address correspondence to: Howard N. Hodis, MD, Atherosclerosis Research Unit, Keck School of Medicine, University of Southern California, 2250 Alcazar St, CSC 132, Los Angeles, CA 90033. E-mail: email@example.com