4 Hormones that Contribute to Osteoporosis in Women
Osteoporosis literally means boneporous, from osteo (bone) and porosis (porous). Healthy bones look like honeycombs under a microscope. They have small holes and pockets of space throughout them, which make them both strong and lighter in weight. Osteoporotic bones look more like cobwebs, with much larger holes throughout them.
Because bones are more porous, they are not always stable. Therefore, having osteoporosis greatly increases risk of bone fractures and breaks. These fractures and breaks can be more life-threatening as we age.
Osteoporosis is commonly thought of as an old woman’s disease, as the disease can occur across a lifetime at all ages and can affect men as well as women. You can help prevent or delay onset and also do testing for early detection of primary osteoporosis, which means the disease is not a result of another underlying condition.
In cases of secondary osteoporosis, the disease is a result of some other underlying condition, often related to hormone imbalances and medications that influence our hormones. Here are four examples of hormones that play a role in bone health and osteoporosis for women.
Three hormones comprise a group referred to as estrogen (or estrogens) and are commonly called estrogen. These hormones are found in both men and women and are responsible for secondary sexual characteristics, which are features that appear during puberty and are not directly related to sexual reproduction. Think of hair growth and voice changes. Estrogens include estrone (E1), estradiol (E2), and estriol (E3).
Estrogen deficiency can occur at any age, though it is most commonly known to occur in older women experiencing perimenopause and menopause. Men have estrogen too though, and both men and women are susceptible to osteoporosis due to low estrogen levels.
In young women, any condition impacting the function of ovaries can cause low estrogen, such as premature ovarian failure, congenital conditions, thyroid disorders, or pituitary dysfunction. Behaviors can also influence estrogen levels, such as excessive exercise.
The parathyroid glands are located above the thyroid in the neck, just in front of the throat. They are responsible for regulating the amount of calcium in blood and bones. Despite being physically close to the thyroid, the parathyroid has no influence on metabolism, the chief thyroid function. The parathyroid glands are solely responsible for ensuring a steady and balanced calcium level in the body, which is vital to healthy nerve and muscle function in addition to bone density.
Think of the parathyroid glands and their hormones like the calcium gatekeepers and transit system. The brain requires calcium to function, and the bones store the calcium. But, the bones also need calcium to retain their structure. The parathyroid releases hormones (called parathyroid hormone or PTH) to make sure the brain, blood stream, and bones have adequate amounts of calcium.
Increased levels of parathyroid cause cells to release their calcium, including bones. Calcium blood levels increase, but calcium bone levels can dangerously decrease, causing osteoporosis. Left untreated, hyperparathroidism (overactive parathyroid) causes bones to become more and more brittle over time, which increases risk of fracture.
As previously mentioned, calcium is vital to muscle function, not only bone health. The hormone cortisol directly and indirectly influences bone calcium levels in order to provide a fuel supply of amino acids to muscles and in response to stress. Also known as hydrocortisone, cortisol is made, stored, and released from the adrenal glands and plays a role in how the body responds to stress, from influencing memory encoding to regulating metabolism, blood sugar levels, and salt and water balance.
Cortisol influences bone density in two ways: triggering bone mineral removal and blocking calcium absorption, which also decreases bone cell growth. Even short bouts of elevated cortisol can influence bone calcium levels, which is why, paradoxically, people we often think of as engaging in healthy exercise can still be susceptible to osteoporosis; engaging in high-stress exercise on a regular basis, such as long-distance running or cycling, also causes short bouts of elevated cortisol and subsequent bouts of low bone density. With this knowledge, it follows that cyclists and runners would be more likely to experience a fracture if they had a bike or running accident.
Elevated cortisol levels are a result of elevated stress. Some of this stress is part of a daily, natural cycle; cortisol is more likely to be high in the morning when the body needs to wake up and get moving. Levels trail off throughout the day as the body prepares for sleep.
Cortisol levels will spike in response to physical and psychological stress or stressful situations, such as strenuous exercise or giving an important presentation at a high-stakes meeting or conference. When we perceive or experience stress, cortisol levels rise to ensure we make it through those stressful situations. In this case, the temporary loss in bone density is beneficial.
Chronic or inescapable stress can lead to consistently elevated cortisol levels, which means consistently low bone density levels and overt hypercortisolism.
Excess production of cortisol or overt hypercortisolism (Cushing’s syndrome) leads to osteoporosis and hip fracture in 70% of cases.
Managing stress and getting plenty of sleep can help reduce cortisol levels and prevent chronically high levels of the hormone that result in a loss of bone density and osteoporosis.
The thyroid is a gland in the neck that sits in front of the throat and is responsible for metabolism regulation, heart and digestive function, muscle control, and brain development. It also plays a role in bone maintenance, though not in terms of blood calcium levels like the parathyroid.
High levels of triiodothyronine and thyroxine in combination with low levels of thyroid stimulating hormone (TSH) contribute to an overactive thyroid, called hyperthyroidism. Essentially, too much thyroxine and too little TSH in the body speeds up the rate of bone loss. Osteoblasts, the cells responsible for building bone, cannot keep up with the pace of bone loss. The result is a loss of overall bone mass. When TSH levels are too low for too long, osteoporosis risk increases.
Bones provide the structure that enables our bodies to move about the world, and bones also serve as the body’s calcium storage. Because calcium is so vital to so many bodily functions, that storage supply constantly fluctuates and is heavily influenced and regulated by a variety of hormones, both directly and indirectly. While some fluctuation is necessary, such as in response to acute stress, chronic bone loss from hormonal imbalances does lead to osteoporosis.
Hormonal imbalances can occur across a woman’s lifetime; do not wait until menopause to start thinking about you or your client’s hormonal health.