Are there symptom-specific testosterone thresholds in aging men?

OBJECTIVE: • To study the association between specific clinical symptoms (e.g. low libido and erectile dysfunction) and testosterone levels and age in order to define symptom-specific testosterone thresholds. MATERIALS AND METHODS: • Serum samples for testosterone determination were obtained from 675 healthy men. • Participants underwent urological examination and completed the Aging Males Symptoms scale, the Beck Depression Index and the International Index of Erectile Function. Overall scores and those from individual questions from the questionnaires were evaluated. • Testosterone levels in men with symptoms were compared with those in men without symptoms. • The risks of clinical symptoms were evaluated using univariate, multiple multinomial regression analyses and Bonferroni correction. RESULTS: • Significant associations between testosterone levels and a number of androgen deficiency symptoms were seen at testosterone levels of 13.5-14.4 nmol/L, but multiple logistic regression analysis revealed confounding effects with age. • Symptoms such as loss of libido, lack of vigour and sexual dysfunction were associated with age rather than with testosterone. • Erectile dysfunction was reported at testosterone levels between 14.65 nmol/L and 14.8 nmol/L, but was again significantly associated with age rather than testosterone levels. • The severity of symptoms significantly increased with decreasing testosterone levels using univariate analysis, but only the relationship with psychological symptoms remained significant after Bonferroni correction. CONCLUSION: • In aging males, androgen deficiency symptoms were reported at normal levels of testosterone, but age was an important confounder. Symptom-specific testosterone thresholds could not be defined.

How much physical activity is needed to maintain erectile function? Results of the Androx Vienna Municipality Study.

OBJECTIVE: To assess the correlation of erectile function (EF) and physical activity (PhA) by using standardized, validated instruments in healthy men. METHODS: A urologist examined 674 men aged 45-60 yr at their place of work. That included a urological physical examination, medical history, and assessment of testosterone (T) and sex hormone-binding globulin; all men completed the 5-item International Index of Erectile Function (IIEF-5) as well as the Paffenbarger score. PhA was assessed in kilojoules per week (4.2 kJ=1 kcal). RESULTS: A positive correlation between the IIEF-5 and the Paffenbarger score (r=0.164, p<0.001) was found. The IIEF-5 score increased with an increasing Paffenbarger score up to a level of 4000 kcal/wk. T revealed a trend to a significant impact on the IIEF-5 score, but showed no association with the Paffenbarger score. The risk of severe erectile dysfunction (ED) was decreased by 82.9% for males with PhA of at least 3000 kcal/wk compared with males with PhA under 3000 kcal/wk (OR=0.171, p=0.018). CONCLUSION: Increasing PhA from 1000 to 4000 kcal/wk may reduce the risk of ED.

Mood changes, body mass index and bioavailable testosterone in healthy men: results of the Androx Vienna Municipality Study.

OBJECTIVE: To determine whether sex hormones alone or in combination with body mass index (BMI) influence mood in men. SUBJECTS AND METHODS: Blood samples were taken from 669 manual workers (aged 43-67 years) to measure sex hormone levels, in particular bioavailable testosterone (BAT). At the same time BMI was calculated. All participants completed the Beck's Depression Inventory (BDI) for the evaluation of depression. Then BMI and BAT were correlated to the BDI scores, to determine a possible interaction. RESULTS: There was a quadratic main effect for BAT on the BDI scores, i.e. an increased risk of depression with an odds ratio of 1.871 (P = 0.029) for hypo- and hypergonadal men. Also, there was an interaction between BAT and BMI, which was mainly detected in underweight and obese men. This U-shaped effect for underweight and obese men was not detected in men with a 'normal' weight, who had a significantly linear decrease in the risk of depression by changing from the hypogonadal to the eugonadal subgroup, as well as for changing from the eugonadal to the hypergonadal subgroup, with a mean odds ratio of 0.513 (P = 0.032). CONCLUSIONS: Depression depends on BAT and BMI; in men of normal weight, an increase in BAT reduces the risk of depression, which is not the case in underweight and obese men. Consequently eugonadal men with normal testosterone levels have the lowest risk of depression.

The impact of age, body mass index and testosterone on erectile dysfunction.

PURPOSE: Erectile dysfunction (ED) may be associated with low serum total testosterone (T), low serum bioavailable testosterone (BAT) and high body mass index (BMI) in aging men. MATERIALS AND METHODS: A total of 675 workers (age range 45 to 60 years old) were entered into this study. Investigations were performed directly at their place of work. Exclusion criteria were abnormal urogenital status, antihypertensive drugs, medication possibly affecting the endocrine function and a history of previous pelvic trauma. T and sex hormone-binding globulin were measured with commercially available assays, and BAT was calculated from T and sex hormone-binding globulin. BMI was assessed and every individual completed a self-administrated questionnaire for erectile function (International Index of Erectile Function [IIEF-5]). RESULTS: T and BAT showed a significantly negative correlation with age and BMI. Each additional year of increase in age caused a decrease in the IIEF-5 score of 0.195 (p <0.001). Increase in BMI by 1 kg/m reduced IIEF-5 by 0.141, independent of age (p =0.005). Multiple logistic regression analyses confirmed the influence of increased age and higher BMI on the risk of ED. The corresponding odds ratio for ED was 1.082 (p <0.001) and 1.076 (p <0.001), respectively. These data indicate an increase in ED risk by 8.2% per year and by 7.6% per kg/m BMI. Severe cases of ED (IIEF-5 score 7 or less) were significantly associated with a decrease in T and BAT. Individuals with low BAT (1 ng/ml or less) had a 3 times higher risk of severe ED compared with men with BAT greater than 1 ng/ml (odds ratio 3.045, 95% CI 1.088 to 8.522, p =0.034). The result of the multiple logistic regression analysis was adjusted to age and BMI, and did not show a significant influence on the incidence of severe ED. CONCLUSIONS: BMI contributes strongly to ED. Low T or BAT are only relevant if IIEF-5 questionnaire results in severe ED.