Serum testosterone, dihydrotestosterone and estradiol concentrations in older men self-reporting very good health: the healthy man study (original) (raw)

2012, Clinical Endocrinology

Objective To determine serum concentrations, intra-individual variability and impact of age-related co-morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E 2) and estrone (E 1) in older men. Design Observational, repeated measures study. Participants Men (n = 325) with 40 years and older selfreporting very good or excellent health. Measurements Standardized history, physical examination and collection of nine blood samples at fixed time intervals were measured 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, E 2 and E 1 (n = 2900, > 99% of scheduled samples) measured by liquid chromatography-tandem mass spectrometry (LC-MS) were analysed 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 (À0•35 nM per body mass index (BMI) unit, P < 0•0001) and ex-smoker status (À1•6 nM, P < 0•001) had significant effects. Serum DHT was increased with age (+0•011 nM per year, P = 0•001) but decreased with obesity (À0•05 nM per BMI unit, P < 0•0001). Serum E 2 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, E 2 and E 1. Non-fasting serum T and DHT were stable over time (day, week, month or 3 months; P > 0•28). Conclusions Serum T, DHT and E 2 displayed no decrease associated with age among men over 40 years of age who selfreport very good or excellent health although obesity and exsmoking status were associated with decreased serum androgens (T and DHT) but not E 2. These findings support the interpretation that the age-related decline in blood T accompanying non-specific symptoms in older men may be due to accumulating age-related co-morbidities rather than a symptomatic androgen deficiency state.