Androgen Decline in the Aging Male

1. See Also
   1. Hypogonadism
   2. Testicular Failure
2. Definition
   1. Primarily sexual and reproductive changes in aging male
3. Epidemiology
   1. Age of onset: 40-70 years old
   2. Prevalence in U.S. (1990): 35 Million men
   3. Prevalence in U.S. (predicted for 2010): 54 Million men
   4. Testosterone decreases after age 30 years
   5. Testosterone is deficient in 86% of men by age 80
4. Physiology: Changes with aging
   1. Erection
      1. Erection takes 2-3 times longer
      2. Prolonged refractory phase
      3. Partially lost Erection difficult to return to full
   2. Ejaculation
      1. Decreased force of ejaculation
      2. Decreased awareness of ejaculation
   3. Testosterone
      1. Serum Testosterone decreases for age over 50 years
         1. Hypogonadism in 20% of men over age 60 years
         2. Hypogonadism in 50% of men over age 80 years
      2. Testosterone levels drop 1% per year ages 40-70 years
   4. Body Composition
      1. Decreased Lean Body Mass/decreased strength
      2. Upper and central body fat increases with age
5. Signs and symptoms
   1. See Testicular Failure
6. Labs
   1. Total Serum Testosterone <200 ng/dl
      1. Ruled out if testosterone >400 ng/dl
      2. Recheck a second value to confirm low testosterone
   2. Free Testosterone (Bioavailable Testosterone) testing indications
      1. Most accurate measure
      2. Low SHBG (Obesity, Type II Diabetes, Hypothyroidism)
      3. High SHBG (Older age)
      4. Wide variation in accuracy among labs
   3. Consider evaluation for secondary cause
      1. See Testicular Failure
      2. Expert endocrinology opinion recommends always obtaining serum pituitary markers when Serum Testosterone is low
      3. Indications to evaluate for pituitary tumor
         1. Serum Prolactin high
         2. Serum LH low
         3. Serum FSH low
      4. Consider other conditions causing low Testosterone
         1. Obstructive Sleep Apnea
         2. Major Depression
         3. Significant acute illness
      5. References
         1. Young (2012) Mayo POIM Conference, Rochester
         2. Bhasin (2010) J Clin Endocrinol Metab 95(6):2536-59
7. Associated Conditions
   1. Associated with Major Depression
      1. Adjusted Hazard ratio: 4.2
      2. Shores (2004) Arch Gen Psychiatry 61:162-7
   2. Osteoporosis
8. Management
   1. See Androgen replacement
      1. Transdermal agents are preferred
   2. Baseline exam prior to starting replacement
      1. Digital Prostate exam
      2. Prostate Specific Antigen (PSA)
      3. Complete Blood Count
9. References
   1. Ayta (1999) BJU 84(1):50-6
   2. Gray (1991) J Clin Endocrinol Metab 73:1016
   3. Kaiser (1999) Med Clin North Am 83(5):1267-78
   4. Lewis (2001) Urol Clin North Am 28(2):209-16
   5. Morales (2000) J Urol 163:705-12
   6. Schow (1997) Postgrad Med 101(3):62-79
   7. Sternbach (1998) Am J Psychiatry 155(10):1310-8