Liz came to see me for a routine examination. In taking her history, I learned that she had her ovaries removed at age 32 for severe endometriosis. At age 54 she was trying to remain active and had started training for a triathlon.

“My back hurts all the time,” she declared when I asked her how she felt.

After completing the physical examination, I told Liz that I wanted to order a bone density scan. I explained that I was concerned about her bones because she had premature menopause due to the surgical removal of her ovaries, and that with her small stature she was at risk of osteoporosis.

This is one of the reasons bone health becomes such a central issue after menopause: bone loss can happen quietly, and the first obvious sign may be a fracture or a scan that shows years of change.

What is osteoporosis?

Osteoporosis is a disorder of the skeletal system that results in decreased bone strength and subsequent susceptibility to fractures. Osteoporotic bones are easily fractured, and even a minimal impact could cause breakage. The hip and spine are the areas most commonly affected.

Hip fractures are especially devastating. They are common reasons for older individuals losing their independence, and can even lead to death if not treated quickly. Fractures can also occur in the spine, which can result in loss of height and chronic back pain.

To understand osteoporosis, it helps to understand what “bone strength” actually means.

Bone strength is determined by bone density and bone quality. Components of this are structural and material in nature:

• Structural properties include bone shape, size, and microarchitecture (the internal structure).
• Material properties include mineralization, collagen composition, and damage accumulation.

How bone density is measured: DEXA and T-scores

Bone mineral density testing is the standard way to measure bone integrity. This testing is performed using dual-energy x-ray absorptiometry (DEXA). The World Health Organization (WHO) has defined criteria for normal and abnormal results.

The T score is utilized and describes the number of standard deviations (SD) in which a person’s results exceeds (positive score) or falls below (negative score) the mean of a young adult group of the same sex.

Here is how the ranges are defined:

• Osteoporosis is the diagnosis when the value falls 2.5 standard deviations (T score of –2.5) or more below the mean.
• Osteopenia or low bone density occurs when the T score is –1.0 to –2.5.
• If the score is greater than –1.0, one’s bones are considered to be of normal density.

These ranges were developed to identify individuals who are at increased risk of fractures. The goal of early diagnosis and prevention is to minimize the incidence of fracture and other morbidity, because fractures can have life-threatening and life-altering consequences.

How osteoporosis occurs

Osteoporosis occurs when the bone density falls to a point that there is an increased risk of fracture with minimal trauma. The risk of developing osteoporosis is determined by the peak bone density achieved during childhood and the rate of bone loss later in life.

Healthy bone is maintained by a balance between the destruction of old, damaged bone and the formation of new bone. This is done through remodeling:

• Cells called osteoclasts remove old bone by producing substances that destroy the old bone.
• Cells called osteoblasts secrete new bone material into the cavity where the old bone was removed.

An individual continues to build bone during childhood and adulthood. The maximum achieved bone mass is complete by age 40, however childhood bone development is the most crucial. The peak bone mass achieved is determined by environmental and genetic factors.

Bone loss occurs because of an imbalance between the activity of the osteoclasts and osteoblasts. Postmenopausal women develop significantly increased bone turnover, which continues for many years after the cessation of ovarian function. This is due to a decrease in estrogen production.

This loss of estrogen leads to an increase in the life span of the osteoclasts (cells that destroy bone) and a shortening of the life span of the osteoblasts (cells that make new bone). Menopause and early menopause are major risk factors due to the increased bone turnover that occurs once estrogen production stops.

Why osteoporosis matters

Osteoporosis is common, and the consequences can be severe. Hip fractures are typically caused by a fall, and they can change a person’s life dramatically.

The outcomes after a hip fracture can be especially sobering:

• Twenty percent of people who experience a hip fracture die within a year of the event.
• Thirty-three percent require nursing home placement.
• Less than thirty-three percent regain their previous level of physical fitness.

Even when fractures are clearly related to fragile bones, many people are never evaluated. Of the people who experience fractures that are obviously due to fragile bones, less than 25 percent are evaluated for osteoporosis.

Given the burden and risks of disability and mortality, this is a disorder that deserves early attention and prevention.

Who is at risk?

Identifying women who are at risk is important so that preventative measures and early treatment can be undertaken. The overall goal is the prevention of fractures.

The following are common factors associated with the development of osteoporosis and related fractures:

• Postmenopausal women
• Early menopause
• Poor calcium absorption
• Low body weight
• Steroid use
• Smoking
• Certain medical disorders
• Certain medications
• Vitamin D deficiency
• History of fractures
• Family history of fractures
• Excessive alcohol consumption

Risk also increases after a first fracture. Once a woman develops one fracture, she is at greater risk of developing a second. One study showed that those with a vertebral fracture have a 19 percent chance of developing a second fracture within 1 year.

What helps: prevention, habits, and fall risk

There are simple strategies that can be adopted by anyone to prevent the development of this problem and related fractures:

• Increase calcium and Vitamin D in your diet or via supplements—1200 mg of calcium and 400–800 international units of Vitamin D.
• Muscle strengthening: weight bearing, aerobic, strength training, and stretching. Protects against osteoporosis, fractures, and falls. Improves flexibility and balance.
• Fall prevention in those at risk: dizziness, poor vision, decreased mobility, poor muscle strength and coordination, and urinary incontinence.
• Smoking cessation.
• Moderate alcohol consumption.

Recommendations for vitamin D and calcium vary by recommender, but in general, calcium is 1000–1200 mg daily, and it should preferably come from dietary sources when possible. Vitamin D is often recommended in the range of 400–1000 IU daily. We are just starting to learn more about vitamin D deficiency, and many people are typically low, so I recommend 1000 units.

Potential concerns of calcium supplementation include the risk of renal stone formation and calcium deposits in the coronary arteries. It’s a good idea to discuss any supplements with your primary care provider, especially if you have medical conditions.

Osteoporosis is preventable and treatable. Regular exercise 3 to 4 times per week for at least 30 minutes has been proven to be effective in maintaining bone density and even reversing bone loss. The other benefits are improved coordination and increased muscle strength, minimizing the risks of falls.

Diagnostic tools should be utilized for those at risk, allowing for early diagnosis and appropriate intervention. All women who have risk factors or who are over age 65 should undergo bone density testing.

Medications for osteoporosis prevention and treatment

There are many medications available for the prevention and treatment of osteoporosis. They improve bone mineral density and have been proven to significantly decrease the risk of fractures. No medication is completely free of risk or side effects, but you can work closely with your health care provider to choose the one that is right for you.

Here is a concise overview of the options described:

• Estrogen (traditional hormone replacement therapy): Proven to improve bone density and reduce fractures of the hip, spine (vertebral), and wrist by preventing bone resorption and supporting bone-building cells. Concerns include the association with breast cancer and increased risk of thromboembolic events such as blood clots and stroke, so it is not recommended as a first-line therapy for osteoporosis when other effective medications exist. Bone loss can increase after discontinuation, so women who stop hormone therapy should be assessed and treated appropriately.
• Bisphosphonates: Destroy osteoclasts, leading to a significant decrease in bone turnover and bone loss. Examples include alendronate, risedronate, ibandronate, and zoledronic acid, with regimens ranging from daily to yearly. Side effects can include gastrointestinal problems, and there is a rare occurrence of necrosis of the jawbone. Stopping may lead to increased bone turnover and decreased bone density.
• Selective estrogen receptor modulators (SERMS): Provide estrogen-like effects on selective tissues while avoiding some undesired effects of estrogen. Raloxifene decreases bone turnover and has been proven to decrease vertebral fractures. Side effects include hot flashes and increased risk of thromboembolic events such as blood clots. It has also demonstrated effectiveness in breast cancer prevention.
• Calcitonin: Inhibits osteoclast activity to prevent bone resorption. Available as an injection or nasal spray, generally well tolerated, and shown to decrease the risk of spine fractures in people with osteoporosis.
• Parathyroid hormone (Teriparatide): A daily subcutaneous injection that appears to stimulate bone formation, with studies showing increased hip and spine density. Adverse effects include nausea, headaches, increased serum calcium levels, and an observed increase in osteosarcoma in animal studies. It is reserved for severe osteoporosis or high fracture risk and should not be used for longer than 2 years; benefits disappear after stopping, so another agent is advised afterward.
• Other medications noted: Denosumab is a monoclonal antibody that decreases osteoclastic activity and was approved by the FDA for postmenopausal osteoporosis. Tibolone has been shown to increase bone mineral density, prevent bone loss, and decrease fractures, but is not currently available in the U.S.

What to take away

Osteoporosis is a condition of thin bones, and the concern relates to how easily bones can be broken. Menopause and early menopause are major risk factors because bone turnover increases when estrogen production stops.

The goal is fracture prevention. That means knowing your risks, using diagnostic tools when appropriate, adopting prevention strategies, and working closely with a health care provider to choose an approach that fits your situation.