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Testosterone Levels Not a Reliable Indicator of Clinically Significant Androgen Deficiency in the Aging Male

Tuesday, 27 July 2004

BERKELEY, CA (UroToday Inc.) - In middle-aged to elderly men several physiologic functions gradually decrease and may result in clinical signs and symptoms of androgen deficiency, namely decrease in libido, erectile dysfunction, depressed mood, and loss of muscle and bone mass. These changes are similar to those observed in untreated male hypogonadism. Since clinical changes in elderly men occur in parallel to the decrease in serum testosterone (T) levels, a causal relationship has been postulated. While physicians increasingly prescribe testosterone supplementation to combat the effects of decreased circulating testosterone, there is considerable controversy over whether the age-associated decrease has clinical significance and whether this "andropause" actually exists.

This article examines the association between total testosterone (TT), calculated free testosterone (FT calc), bioavailable testosterone (BT), and various clinical and metabolic parameters of androgen action in 51 healthy males aged 55 to 75 years old. The parameters included serum levels of sex hormone binding globulin, estradiol and lipid profile after an overnight fast, questionnaires assessing clinical symptoms (the androgen deficiency in aging males or ADAM interview, and the Dalbert questionnaire), erectile function (the International Index of Erectile Function or IIEF) and mood (Beck-Depression Inventory or BDI), along with bone mineral density or lean body mass. M. Christ-Crain and colleagues reported their results from Luzerne, Switzerland and published them in the August, 2004 issue of The Journal of Urology.

The mean age of the patient population was 60.9 years. Hypogonadism was defined as a mean TT value of 2.5 standard deviations below the mean value of a young healthy control population (mean TT 21.7 nmol/l). Using this definition, the calculated TT level to diagnose hypogonadism was 11.7 nmol/l or less and 47.1% of men in the study population had TT values less than this. The intra-individual day-to-day variance of TT levels was 14.8%. Of the men with initial hypogonadal TT levels, 25% were within the normal range on repeat testing. In contrast, 24% of those with normal initial values had hypogonadal levels on second measurement.

Analysis revealed that there was no association between testosterone levels and the BDI or Dalbert questionnaires. Similarly, correlations between different T levels and the IIEF were not significant. T values in patients with a positive and negative response to the ADAM questionnaire were also not significantly different.

These findings suggest that in middle-aged to elderly men, signs and symptoms of the aging male are likely multifactorial and not solely related to the age-related decrease in testosterone. The authors found weak or even absent correlations between serum T concentration, and clinical as well as metabolic measures of androgen action.

J Urol. 2004; 172(2):624-7