Author:

Keywords:

AGE, cancer, CANCER, cardiovascular disease, CARDIOVASCULAR-DISEASE, DIHYDROTESTOSTERONE, Endocrinology & Metabolism, ESTRADIOL, HEALTH, Life Sciences & Biomedicine, mortality, OLDER MEN, RISK, Science & Technology, sex hormone-binding globulin, testosterone, Adult, Aged, Aging, Biological Specimen Banks, Cardiovascular Diseases, Cause of Death, Diabetes Mellitus, Type 2, Humans, Male, Middle Aged, Mortality, Neoplasms, Sex Hormone-Binding Globulin, Testosterone, United Kingdom, : Testosterone, 1103 Clinical Sciences, 1114 Paediatrics and Reproductive Medicine, 3202 Clinical sciences

Abstract:

CONTEXT: Serum testosterone concentrations decline with age, while serum sex hormone-binding globulin (SHBG) concentrations increase. OBJECTIVE: To analyze associations of baseline serum testosterone and SHBG concentrations, and calculated free testosterone (cFT) values, with all-cause and cause-specific mortality in men. DESIGN, SETTING, AND PARTICIPANTS: The UK Biobank prospective cohort study of community-dwelling men aged 40-69 years old, followed for 11 years. MAIN OUTCOME MEASURES: All-cause, atherosclerotic cardiovascular disease (CVD) and cancer-related mortality. Cox proportional hazards regression was performed, adjusting for age, waist circumference, medical conditions, and other covariates. Models for testosterone included SHBG and vice versa. RESULTS: In a complete case analysis of 149 436 men with 10 053 deaths (1925 CVD and 4927 cancer-related), men with lower testosterone had a higher mortality rate from any cause (lowest vs highest quintile, Q1 vs Q5, fully-adjusted hazard ratio [HR] = 1.14, 95% confidence interval [CI] = 1.06-1.22, overall trend P < 0.001), and cancer (HR = 1.20, CI = 1.09-1.33, P < 0.001), with no association for CVD deaths. Similar results were seen for cFT. Men with lower SHBG had a lower mortality rate from any cause (Q1 vs Q5, HR = 0.68, CI = 0.63-0.73, P < 0.001), CVD (HR = 0.70, CI = 0.59-0.83, P < 0.001), and cancer (HR = 0.80, CI = 0.72-0.89, P < 0.001). A multiply imputed dataset (N = 208 425, 15 914 deaths, 3128 CVD-related and 7468 cancer-related) and analysis excluding deaths within the first 2 years (9261, 1734, and 4534 events) yielded similar results. CONCLUSIONS: Lower serum testosterone is independently associated with higher all-cause and cancer-related, but not CVD-related, mortality in middle-aged to older men. Lower SHBG is independently associated with lower all-cause, CVD-related, and cancer-related mortality. Confirmation and determination of causality requires mechanistic studies and prospective trials.