OBJECTIVE: To determine serum concentrations, intra-individual variability and impact of age-related co-morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E2 ) and estrone (E1) in older men.
DESIGN:Observational, repeated measures study.
PARTICIPANTS:Men (n=325) 40 years and older self-reporting very good or excellent health.
MEASUREMENTS: Standardized history and physical examination, 9 blood samples at fixed time intervals over 3 months (three at 20 min intervals on days 1 (fasting) and 2 (non-fasting), one at days 7, 30 and 90). Serum T, DHT, E2 and E1(n=2900, >99% of scheduled samples) measured by liquid chromatography-tandem mass spectrometry (LC-MS) were analyzed by linear mixed model analysis with fasting, age and obesity as covariables.
RESULTS: Mean serum T did not vary with age (p=0.76) but obesity (-0.35 nmol/L per body mass index (BMI) unit, p< 0.0001) and ex-smoker status (-1.6 nmol/L, p< 0.001) had significant effects. Serum DHT was increased with age (+0.011 nmol/L per year, p=0.001) but decreased with obesity (-0.05 nmol/L per BMI unit, p< 0.0001). Serum E2 did not vary with age (p=0.31) or obesity (p=0.12). Overnight fasting increased (by 9-16%, all p< 0.001) and reduced variability in morning serum T, DHT, E2 and E1. Non-fasting serum T and DHT were stable over time (day, week, month or 3 month; p>0.28).
CONCLUSIONS: Serum T, DHT and E2 displayed no decrease associated with age among men over 40 years of age who self-report very good or excellent health although obesity and ex-smoking status were associated with decreased serum androgens (T, DHT) but not E2 . These findings support the interpretation that the age-related decline in blood T accompanying non-specific symptoms in older men may be due accumulating age-related co-morbidities rather than a symptomatic androgen deficiency state.
Written by:
Sartorius G, Spasevska S, Idan A, Turner L, Forbes E, Zamojska A, Allan C, Ly L, Conway A, McLachlan R, Handelsman D. Are you the author?
Andrology Department, Concord Hospital; ANZAC Research Institute, University of Sydney, Sydney, NSW, 2139, Australia.
Reference: Clin Endocrinol (Oxf). 2012 May 7. Epub ahead of print.
doi: 10.1111/j.1365-2265.2012.04432.x
PubMed Abstract
PMID: 22563890
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