What is Hypogonadism?
Hypogonadism is a medical condition which causes the male testicles to produce less testosterone, and the female ovaries to produce less estrogen. The two most common causes are referred to as primary hypogonadism and secondary hypogonadism. Primary hypogonadism is a problem directly within the testicles/ovaries which causes insufficient hormone production, whereas secondary hypogonadism occurs when these organs do not receive the necessary “message” from the brain to produce hormones.
In men, hypogonadism becomes increasingly more common with age… impacting 12% of men at 50 years old, and 49% of men in their 80s. All women will ultimately experience “natural hypogonadism” following menopause, but may experience hypogonadism prior to menopause as well.
When you are young, testosterone and estrogen are crucial for normal sex organ development, fertility, and libido. Did you know that these hormones also help to regulate bone metabolism? Abnormally low levels of testosterone and estrogen have been linked to osteoporosis and fractures in both men and women.
How is Hypogonadism Diagnosed?
The symptoms experienced by men with hypogonadism tend to be quite vague, making it tricky for your doctor to diagnose. Men may experience decreased libido, infertility, erectile dysfunction, decreased testicular size, loss of muscle mass and strength, depression, and fatigue. Hypogonadism in women can lead to a loss of menstruation, hot flashes, loss of body hair, and low sex drive.
The following lab tests aid in the diagnosis of hypogonadism, and also provide information regarding where the problem is coming from.
- Fasting Morning Testosterone. Testosterone is the male sex hormone produced by the testicles which influences libido, mood, energy, muscle mass, and bone strength. Testosterone levels fluctuate throughout the day by as much as 35%, but are consistently the highest in the morning. If your morning testosterone levels are lower than the normal range of 300-1000 ng/dL, this confirms hypogonadism.
- Serum Estradiol (Estrogen). Estrogen is the female sex hormone produced by the ovaries. It aids in the development of female characteristics including breast development, regulation of the menstrual cycle, and also in bone health. Low levels of estrogen confirms the diagnosis of hypogonadism in women.
- Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). These hormones are released by the pituitary gland in your brain. They work together to stimulate the testicles and ovaries to produce sex hormones. If you have low sex hormone levels, these blood tests aid in determining the source of the problem. LH and FSH will be high if the testicles/ovaries are the problem, and they will be low if the pituitary gland is the problem.
Simply put, low testosterone/estrogen levels confirm the diagnosis of hypogonadism. LH and FSH show us where the problem is and how best to treat it.
How Does Hypogonadism Impact Your Bones?
Hypogonadism among men has drawn considerable attention as a secondary cause of osteoporosis, and for good reason! It has been reported as the cause of weak bones and fractures in 8-15% of men who are diagnosed with osteoporosis. Sex hormones including both testosterone and estrogen have been shown to help regulate bone metabolism.
Direct Influence of Testosterone on Bone Cells
- There are testosterone receptors in multiple bone cells, including bone building osteoblasts, bone breakdown osteoclasts, and osteocytes (bone maintenance cells). When testosterone and other hormones bind to these receptors, it influences the activity of your bone cells. Studies have been performed involving patients with a condition called androgen insensitivity syndrome—where body cells do not respond to testosterone (simulating hypogonadism). When testosterone is low or cannot interact with bone cells, these people have lower bone density compared to the general population.
Indirect Influence of Testosterone on Bone Cells
- In both men and women, testosterone is converted to the hormone estrogen by an enzyme known as aromatase. Estrogen then binds to estrogen receptors in osteoblasts and osteoclasts, which helps maintain bone strength. Low testosterone or aromatase levels in men leads to less estrogen, and studies have shown that this is associated with low bone density and osteoporosis in men.
Influence of Testosterone on the Rest of the Body
- Outside of the skeletal system, testosterone levels have been linked to muscle strength and physical performance. Hypogonadism can lead to muscle weakness and predispose people to falls, which is a known risk factor for fractures.
How Can Those With Hypogonadism Improve Their Bone Health?
For all men and women with hypogonadism, the first step in selecting the best treatment lies in determining whether low hormone levels are due to primary or secondary hypogonadism.
Those who have symptoms caused by primary hypogonadism may be candidates for hormone replacement. The Endocrine Society suggests testosterone replacement for men who experience symptoms related to the disease, as well as those with low bone density. Women with primary hypogonadism may be candidates for hormone replacement if they are 60 years old or younger, whereas women older than 60 generally should avoid estrogen replacement since it has been linked to side effects including breast and endometrial cancer, stroke, and blood clots. Both men and women with increased fracture risk may also consider osteoporosis medications to improve bone density.
Those who have secondary hypogonadism should be evaluated by a specialist to determine if a cure is available. Correcting the underlying problem may bring hormone levels back into the normal range, and in many cases no other treatment is required. If a cure is not available, treatment would consist of hormone replacement and osteoporosis medications.