The Health Effects of Age‐Related Declines in Testosterone and Reproductive Hormones

Abstract

This thesis examines cross-sectional and longitudinal associations between serum testosterone and other reproductive hormones with a range of health outcomes. Men aged 70 years and older from the Concord Health and Ageing in Men Project (CHAMP) were assessed at baseline (2005-2007, n=1705), 2-years follow-up (2007-2009, n=1367) and 5-years follow-up (2010-2013, n=958). At all assessments, testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) were measured by liquid chromatography-tandem mass spectrometry, and SHBG, LH, and FSH by immunoassay. Cross-sectional and longitudinal data were collected on self-rated health, health-related quality of life, functional disability, muscle mass and strength, cardiovascular disease and diabetes risk factors, sexual function, bone mineral density, falls and fractures, and cognitive function. Analyses did not find that men with low T were more likely to have declining health across a range of outcomes except for decline in functional ability over the follow-up period. This suggests that the lowering of circulating T may be a consequence, rather than a cause, for some poor health outcomes in older men. The research in this thesis also reported statistically significant associations between E1 and a range of health outcomes which suggest that serum E1 in men may be an important novel health biomarker.