Sex hormone trajectories in ageing men and their health implications remain unclear. We examined longitudinal trajectories and associations of testosterone (T), dihydrotestosterone (DHT), estradiol (E2), luteinising hormone (LH) and sex hormone-binding globulin (SHBG) in oldest old men.
We studied 1,025 community-dwelling men in Perth, Western Australia, who had paired blood samples at baseline (2001-04) and follow-up (2011-12).
Plasma T, DHT and E2 were assayed using mass spectrometry, LH and SHBG by immunoassay and free T calculated (cFT). Cut-offs for low T and LH were based on reference ranges from very healthy men aged 70-89 years. Physical performance was assessed at follow-up. Correlations and covariate-adjusted P-values were determined.
Median age was 75.1 years at baseline with 8.6 years follow-up. Longitudinal change in T was -2.0%/year, DHT -7.2%/year, LH +7.5%/year, SHBG +5.6%/year while E2 remained stable. Annualised increases in LH correlated with decreases in T and DHT (r=-0.20, P<0.0001 and r=-0.12, P=0.0035 respectively). Higher baseline T correlated with better physical performance at follow-up (e.g. Step test r=0.07, P=0.03), as did higher baseline DHT (e.g. Time to Sit-Stand [TSS, higher score indicates poorer performance] r=-0.07, P=0.01). Larger annualised increases in LH predicted poorer physical performance at follow-up (e.g. TSS r=0.14, P=0.001). Higher T at follow-up was associated with better physical performance (e.g. TSS r=-0.07, P=0.04), as were higher DHT and lower LH. At baseline 24 men (2.4%) had abnormally high LH (>16 IU/L); at follow-up 175 (17.4%) had high LH of whom 70 had low T (<6.4 nmol/L).
Annualised increases in LH are associated with declines in T and DHT, and predict poorer subsequent physical performance in oldest old men. Men transitioning from 8th to 9th decades exhibit biochemical evidence of progressively impaired testicular endocrine function, warranting further evaluation.