Endo

Androgen Decline in the Aging Male

search

Androgen Decline in the Aging Male, Male Menopause, Male Climacteric, Andropause, Age-Associated Hypogonadism in Men

  • Definition
  1. Primarily sexual and reproductive changes in aging male
  • Epidemiology
  1. Age of onset: 40-70 years old
    1. Decline typically starts after age 40 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
  • 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
  • Labs
  1. See Male Hypogonadism
  2. Total Serum Testosterone <300 ng/dl (in the morning, or 2 within 2 hours of awakening)
    1. Ruled out if testosterone >400 ng/dl
    2. Recheck a second value to confirm low testosterone
  3. 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
  4. Consider evaluation for secondary cause
    1. See Testicular Failure
    2. Always obtain serum pituitary markers when Serum Testosterone is <150 ng/dl (expert endocrinology opinion)
    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 [PubMed]
  • Associated Conditions
  1. See Androgen Replacement
  2. Precautions
    1. Androgen Replacement is not FDA approved for typical age related testosterone decrease
    2. Approved for other causes of Male Hypogonadism (e.g. Chemotherapy, infection, Pituitary Lesion)
  3. Transdermal agents are preferred
  4. Baseline exam prior to starting replacement
    1. See Androgen Replacement
    2. Digital Prostate exam
    3. Prostate Specific Antigen (PSA)
    4. Complete Blood Count (or Hematocrit)