Endocrine Journal 2015, 62 (9), 777-786
Testosterone, dihydrotestosterone and estradiol are differentially associated with carotid intima-media thickness and the presence of carotid plaque in men with and without coronary artery disease Yi X. Chan1), 2), Matthew W. Knuiman3), Joseph Hung1), 4), Mark L. Divitini 3), David J. Handelsman5), John P. Beilby6), 7), Brendan McQuillan1), 4) and Bu B. Yeap1), 2) 1)
School of Medicine and Pharmacology, University of Western Australia, Western Australia, 6009, Australia Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Western Australia, 6150, Australia 3) School of Population Health, University of Western Australia, Western Australia, 6009, Australia 4) Department of Cardiovascular Medicine, Sir Charles Gairdner Hospital, Western Australia, 6009, Australia 5) ANZAC Research Institute, New South Wales, 2138, Australia 6) PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Western Australia, 6009, Australia 7) School of Pathology and Laboratory Medicine, University of Western Australia, 6009, Australia 2)
Abstract. Clarifying the relationship of sex hormones to preclinical atherosclerosis could illuminate pathways by which androgens are associated with cardiovascular events and mortality. Our aim was to determine hormone profiles associated with carotid intima-media thickness (CIMT) and carotid atheroma, in men with and without known coronary artery disease (CAD). We included 492 community-based men aged 20-70 years (Group A) and 426 men with angiographically proven CAD aged 50% stenosis . The CUPID cohort represents a cohort of men with a defined phenotype of proven coronary atherosclerosis, and was designated Group B. The University of Western Australia Human Research Ethics Committee and the Sir Charles Gairdner Hospital Research Institutional Ethics Committee approved the study and all participants provided written informed consent. Assessment of medical comorbidities A self-administered questionnaire was used to report the prevalence of smoking, hypertension, hyperlipidaemia, diabetes, angina pectoris, myocardial infarction, stroke, or a family history of premature onset coronary or cerebrovascular disease. Resting blood pressures and anthropometric measurements (height, weight, waist and hip measurements) were taken from all subjects in an identical manner [23, 24]. Assessment of CIMT and carotid plaque Bilateral carotid B mode ultrasound was performed on all subjects using a 7.5-MHz annular phased-array transducer on an interspec (Apogee) CX 200 ultrasound machine. The ultrasound study was used to determine the presence of focal carotid plaque and to measure the mean common carotid artery intimal-medial wall thickness as previously described . Carotid atheromatous plaque was defined as a clearly identified area of focal increased thickness of ≥1mm of the intimamedia layer.
Sex hormones and carotid atherosclerosis
Laboratory assays Fasting blood samples were collected in the early morning in all subjects. Serum was prepared immediately after phlebotomy and stored at -80 degrees Celsius until assayed. Sera were assayed in 2013. Serum T, DHT and E2 were quantified within a single LC-MS run without derivatization, using atmospheric pressure photoionization in positive mode for androgens and negative mode for oestrogens, from 200µL samples. Between-run imprecision was 8.6% at 5.3 nmol/L and 7.9% at 26.9 nmol/L for T, 11.3% at 1.3 nmol/L and 9.1% at 5.3 nmol/L for DHT, and 14.5% at 73 pmol/L and 9.9% at 279 pmol/L for E2. Luteinising hormone (LH) was assayed using a 2-step noncompetitive chemiluminometric immunoassay (Abbot Architect, Abbott Diagnostics, North Ryde, NSW, Australia), with between run imprecision of 5.6% at 4.8 IU/L. Sex hormonebinding globulin (SHBG) was assayed using a solidphase, two-site enzyme immunometric assay with chemiluminescent substrate (Immulite 2000Xi; Siemens Healthcare, Bayswater, Vic., Australia), with between run imprecision of 3.4% at 39.4 nmol/L. Free T was calculated using an empirical formula, which provides closer concordance with measured free T compared to calculations based on equilibrium binding equations . Statistical analysis Baseline descriptive data were shown as mean and standard deviations (SD) or percentages (%). Comparisons of means were performed using t tests and comparison of proportions using chi-square tests. Adjusted associations between cardiovascular risk factors (independent variable) and endogenous sex hormone levels and SHBG (dependent variable) were assessed using linear regression models. Adjusted associations between endogenous sex hormone levels and SHBG (independent variables) with CIMT were assessed using linear regression models, and their associations with presence of carotid atheromatous plaque using logistic regression models. Adjustments were made for variables that could conceivably confound the analyses, namely age, smoking, alcohol consumption, and body mass index (BMI) (comprising Model 1), and diabetes, CVD history (CUDAS only), systolic blood pressure (SBP), hypertension, lipid lowering therapy, cholesterol, high density lipoprotein (HDL)-cholesterol, (log) triglycerides (TG) and (log) C-reactive protein (CRP) (comprising Model 2). A two-tailed p value of