Osteoporosis Explained: Causes, Symptoms, And Treatments

Osteoporosis is a condition in which the bones become thin, weak, and prone to fractures. According to the National Osteoporosis Foundation, 10 million Americans have osteoporosis and another 44 million have low bone density, making them particularly prone to develop osteoporosis. Osteoporosis leads to an estimated 2 million broken bones in the United States each year. Breaking a hip because of osteoporosis can lead to permanent disability, and can even increase the likelihood of dying in the year following the fracture. In addition to the toll it can take on individuals, osteoporosis also costs the American healthcare system $19 billion every year.

And if you think osteoporosis is something you don't need to worry about until you're much older, think again. As WebMD explains, bone thinning can happen at any age and often has no symptoms until the first broken bone. While the hormonal changes of menopause put women at significantly higher risk for osteoporosis, a number of factors can increase an individual's chances of getting osteoporosis at a younger age. These include low body weight, smoking, not getting enough exercise, a history of eating disorders, celiac disease, and steroid use.

Fortunately, there are many steps you can take to prevent osteoporosis and keep your skeleton strong and sturdy well into your golden years.

Bone is dynamic

To better understand osteoporosis, first you need to know a little about bone structure. 

We tend to assume that our bones stop changing once we reach adulthood, but this isn't true. Bone is a dynamic tissue. According to Lumen Learning,there are actually two types of tissue that make up our bones: compact (cortical) and cancellous (spongy). The outer layer of every bone is made up of compact tissue, in which bone cells are densely packed into a matrix. Underneath this hard exterior is the cancellous bone tissue, which is lighter and less dense and allows for compression in response to stress. There are also several types of bone cells. Osteocytes are mature bone cells, while osteoblasts create new bone and osteoclasts break down bone. Through the actions of osteoclasts and osteoblasts, bone tissue is constantly being broken down and rebuilt — a process known as bone remodeling.

Bone remodeling allows bones to grow thicker and stronger in response to exercise and other forms of stress (via the Mayo Clinic). The rate at which bone is remodeled varies in different parts of the skeleton, and even within different parts of a single bone. It also changes over our lifetime. Up until about age 30, when people reach their maximum bone density, the amount of new bone being built exceeds the amount of bone being broken down. As we age, however, the activity of bone-destroying osteoclasts starts to outpace the activity of bone-building osteoblasts, and we lose bone density.

The role of calcium and vitamin D in bone health

We've had it drilled into our heads since we were kids that calcium builds strong bones, and that's quite literally the case. As American Bone Health explains, "when your body makes new bone tissue, it first lays down a framework of collagen. Then, tiny crystals of calcium from your blood spread throughout the collagen framework." These calcium crystals fill in all the gaps in the "web" of collagen. Collagen makes bones flexible, while calcium makes them strong.

The vast majority of calcium in the body — a staggering 98% of it — is found in our bones and teeth (via the National Institutes of Health). But that doesn't necessarily mean it stays there forever. The body uses our bones as a sort of calcium "bank," making "deposits" and "withdrawals" of this important micronutrient as needed. (Although they contain calcium, our teeth don't experience this same type of fluctuation). Our bodies aren't very good at absorbing calcium from the foods we eat, but vitamin D significantly improves the amount of calcium our digestive tract can absorb.

When circulating levels of calcium are too low, hormonal triggers cause osteoclasts to break down bone, releasing calcium into the bloodstream (via American Bone Health). On the other hand, osteoblasts require calcium to create new bone (via Healthline). So consuming — and actually absorbing — enough calcium is essential to prevent your body from "poaching" calcium from your bones.

Measuring bone density

As the Mayo Clinic explained, doctors use a test known as a bone mineral density (BMD) scan to measure bone density and decide if an individual has or is on the road to developing osteoporosis. This test uses x-rays to determine how much calcium and other bone-building minerals are present in a particular volume of bone. The spine and the hip are the areas most commonly tested, although the bones in the forearm may also be scanned. BMD scans give two results, each of which uses a bell curve and standard deviations to determine how your bone mass compares to others'. Your Z-score compares your bone density to an average person of your same age and sex, while the T-score compares your bone density to an average healthy young adult of your same sex (that is, someone of your gender at peak bone density).

A Z- or T-score of 0 means you're at the top of the bell curve and your bone density is average. A positive Z- or T-score means your bones are more dense than average, while a negative Z- or T-score means your bones are less dense than average. For example, a Z-score of 1 means your bones are one standard deviation away from average in the "more dense" direction, whereas a score of -2 means your bones are two standard deviations away from average but in the "less dense" direction.

Diagnosing osteoporosis and osteopenia

According to the NIH Osteoporosis and Related Bone Diseases National Resource Center, doctors use the T-score results from a bone mineral density (BMD) scan (rather than the Z-score) to diagnose osteoporosis or osteopenia. A T-score of -1 or above is considered normal bone density. So your bones can actually be one standard deviation below average peak bone mass for someone of your gender and still considered totally fine. A T-score between -1 and -2.5 indicates low bone mass, also known as osteopenia. A T-score of -2.5 or below indicates osteoporosis. If a person's T-score is -2.5 or lower and they've also had one or more fractures as a result of their osteoporosis, this is considered severe osteoporosis.

Many people assume that if you have osteopenia it's destined to devolve into osteoporosis. While it's true that people with osteopenia are at a significantly higher risk of developing osteoporosis later on, this isn't a certainty. Hereditary factors or a low body weight can cause someone to have bones that are naturally less dense than average, but if they take the proper precautions, their osteopenia won't develop into osteoporosis as they age. Other individuals diagnosed with osteopenia once had normal bone density and the diagnosis indicates that their bones are starting to weaken. If someone has osteopenia, it's useful to compare multiple BMD scores from that individual over time to see if their low bone mass is staying stable or worsening.

Demographic factors that increase your risk for osteoporosis

There are a number of factors that can increase a person's risk for osteoporosis. Some are within our ability to control, while others are not. When it comes to risk factors beyond our control, age and sex are the two biggest. Among those age 50–59, for instance, 6.8% of women and 3.4% of men have osteoporosis. Among Americans age 60–69, 12.3% of women and 3.3% of men have the condition. In the next decade of life, those numbers increase to 25.7% and 5%, respectively. For those age 80 and older, 34.9% of women and 10.9% of men have osteoporosis (via the United States Bone and Joint Initiative). Asian Americans are significantly more likely to have osteoporosis than other ethnic groups, followed by Hispanic Americans. Black Americans have the lowest rates of osteoporosis (via the Centers for Disease Control and Prevention).

Why are women so much more likely to get osteoporosis as they age? It comes down to sex hormones. Lower levels of sex hormones tend to weaken bone, so when menopause hits, the drop in estrogen can take a toll on bone density. Drops in testosterone in men are also bad news for bone health, but these drops tend to be less dramatic. Body frame also has an impact, as smaller individuals are more likely to have less dense bones to begin with, making them more prone to osteoporosis as they age (via the Mayo Clinic).

Medical conditions that increase your risk for osteoporosis

According to the Mayo Clinic, there are a number of medical conditions that can increase your risk of osteoporosis and may cause the condition to appear at a younger age. Because other hormones besides sex hormones can impact bone density, certain endocrine disorders may make osteoporosis more likely. These include hyperthyroidism (an overactive thyroid) or individuals with hypothyroidism (an underactive thyroid) who take too much synthetic thyroid hormone for their condition. An overactive parathyroid gland (which controls calcium balance in the body) or overactive adrenal glands can also lead to osteoporosis.

Gastrointestinal conditions such as celiac disease and inflammatory bowel disease (which includes Crohn's disease and ulcerative colitis) increase an individual's risk for osteoporosis because they can lead to impaired calcium absorption. Bariatric surgery can also hinder proper mineral absorption. Eating disorders such as anorexia that include heavy restriction can lead to osteoporosis because of insufficient calcium intake, negative changes to sex hormone levels, and dangerously low body weight. Other medical conditions associated with increased risk for osteoporosis include kidney disease, liver disease, cancer, and rheumatoid arthritis.

Long-term use of corticosteroids to treat conditions such as rheumatoid arthritis, asthma, inflammatory bowel disease, and lupus interferes with the bone-building process and significantly increases risk for osteoporosis. Other medications that may negatively impact bone density include anti-seizure drugs, reflux medications, cancer therapies, and drugs to prevent rejection after an organ transplant.

Diet and lifestyle factors that impact osteoporosis risk

While it may seem like the major risk factors for osteoporosis are totally or at least largely out of your control, there are plenty of things you can do to lower your osteoporosis risk. As the Mayo Clinic explained, when it comes to diet, it's critical to get plenty of bone-building calcium throughout your life. Without it, bones won't be as strong even at their peak density, bone density will begin to diminish sooner, and individuals are more prone to fractures. Regularly consuming more than two alcoholic beverages a day also weakens bones. Although the exact reason is still unclear, it also appears that tobacco use weakens bones.

Not getting enough exercise is also a major risk factor for osteoporosis. Physical activity produces stress (the good kind) on our bodies, and over time our bones adapt by getting stronger. When it comes to building and maintaining bone density, weight-bearing and resistance exercises have the biggest impact (via the NIH Osteoporosis and Related Bone Diseases National Resource Center). Unfortunately, most Americans don't get the exercise they need to build strong bones. For example, only 21.9% of women and 30,2% of men engage in the recommended twice-weekly sessions of muscle-strengthening exercise (the kind that also builds bones). This discrepancy in exercise habits may also contribute to higher osteoporosis rates among women (via Popular Science).

Osteoporosis symptoms

Although catching and addressing osteoporosis early leads to the best outcomes, this is easier said than done because osteoporosis is often a "silent" disease. As Healthline noted, weakening bones often produce no noticeable symptoms until a bone breaks and the condition is quite advanced. This lack of warning signs means it's important for individuals at higher risk for osteoporosis because of their age, medical history, or other risk factors be preemptively screened using a DEXA scan to gauge their bone density.

In the early stages of osteoporosis, receding gums may be a sign that you're losing bone mass in your jaw (and, by extension, other parts of your body). Reduced grip strength in your hand may also indicate weakening bones. In more advanced cases of osteoporosis, the vertebrae of the spine can collapse because of compression fractures. Loss of height because of these compression fractures is one of the most obvious symptoms of osteoporosis. Compression fractures of the spine can be very painful, because the collapsed vertebrae can pinch nerves that branch out from the spinal column. The compression of vertebrae may also cause curvature of the upper back (kyphosis or hunchback). This, in turn, can lead to neck pain and may even cause shortness of breath because the altered shape of the spine prevents the lungs from expanding fully.

Fractures

Broken bones are the most serious consequence of osteoporosis. According to the National Osteoporosis Foundation, one in two women and one in four men over the age of 50 will break a bone as the result of advanced osteoporosis. For older adults, broken bones aren't just a painful inconvenience; they can lead to permanent disability and even increase the risk of death. Six months after a hip fracture, only 15% of individuals with osteoporosis can walk unaided across a room. Roughly half of people who suffer a hip fracture because of osteoporosis never regain their previous level of mobility, and one-quarter end up in nursing homes. Most alarming, 24% of people age 50 and over who experience a hip fracture because of osteoporosis will die in the year following the fracture.

The vertebrae, hip, and wrist are the most commonly broken bones. Spinal compression fractures are twice as common as hip and wrist fractures (via OrthoInfo). Most fractures happen because of a fall, but even a minor fall could be enough to break a weakened bone. Normal activities such as bending, lifting, or even coughing can also cause fractures (via the NIH Osteoporosis and Related Bone Diseases National Resource Center). Some breaks, particularly in the hip, may require surgery, while others can heal on their own. Osteoporosis doesn't affect the healing process, although individuals tend to heal more slowly in general as they age. Most fractures will heal in 6 to 12 weeks (via the Royal Osteoporosis Institute).

Fall prevention

The International Osteoporosis Foundation explained that although advanced osteoporosis can lead to fractures from something as innocuous as bumping into a piece of furniture or sneezing, most fractures occur because of a fall. So an important part of living with osteoporosis is minimizing the risk of falling. Approximately one-third of individuals over 65 fall each year, and there are both extrinsic (external) and intrinsic (personal) risk factors that increase an individual's chance of falling. Extrinsic factors include home hazards such as slippery floors, anything on the floor that can be tripped over, poor lighting, and unstable furniture. Outside, hazards such as uneven surfaces, wet or icy pavement, and high curbs can easily lead to a fall. Intrinsic factors include impaired balance, muscle weakness, vision problems, impaired feeling in the legs, slow walking speed, and the use of medications that cause dizziness.

There are many things individuals with osteoporosis and their families can do to minimize the risk of falling. Exercise to strengthen muscles and improve balance and mobility is extremely important. Fall-proofing a home includes measures such as installing handrails in the bathroom for added support, using nonskid shower mats for added traction, ensuring plenty of bright light throughout the home, and keeping the floor clear of tripping hazards. External hip protection (essentially a helmet for your hips made of a propylene or polyethylene shell) can also reduce the likelihood of a hip fracture if someone does fall.

Preventing osteoporosis with diet and supplements

When it comes to preventing osteoporosis, diet is an obvious place to start for building and maintaining bone mass. It's important to get the recommended 1,000–1,200 milligrams of calcium daily (depending on gender and age), preferably from food. It's also important to get the recommended 800 IU of vitamin D daily, whether from sunlight, food, or supplements to ensure the calcium is properly absorbed (via the Cleveland Clinic).

Given the fact that calcium is so important for building strong bones, it makes sense that the more calcium you consume, the less likely you are to get osteoporosis. The research, however, is more mixed than you might think. In its analysis of past research, the National Institutes of Health (NIH) noted that some studies have shown a correlation between increased calcium intake and bone density, but in some cases these results are seen only in women. In other instances, no direct connection between the two factors can be found. The NIH also pointed out that "for the most part, the observational evidence does not show that increasing calcium intakes reduces the risk of fractures and falls in older adults." Despite sometimes contradictory research results, the Food and Drug Administration (FDA) allows manufacturers to make the health claim that use of calcium supplements reduces the risk of osteoporosis.

Preventing and managing osteoporosis with exercise

According to the NIH Osteoporosis and Related Bone Diseases National Resource Center, getting plenty of exercise throughout your life is one of the best things you can do to keep osteoporosis at bay. Weight-bearing exercises, which force the body to work against gravity, are best for building and maintaining bone mass. These include activities such as walking, running, climbing stairs, dancing, and playing sports like soccer or basketball. Basically, any activity in which your body is supporting its own weight and moving around counts as a weight-bearing exercise. While activities like swimming and cycling have many other benefits, they don't count as weight-bearing exercises. Resistance training, including lifting weights and doing bodyweight exercises, also maintains and improves bone density.

Many people with osteoporosis assume that exercising will increase their risk for a bone fracture, but the Mayo Clinic noted that the opposite is true. Exercising strengthens bones and muscles and improves balance and flexibility, making falls (and fractures due to falls) less likely. Exercise can also reduce the pain associated with more advanced osteoporosis. There are, however, certain movements people with osteoporosis should avoid. High-impact activities such as running and jumping can increase fracture risk if your bones are already quite weak. People with osteoporosis should also avoid movements requiring forceful bending or twisting of the spine, since these can increase the risk of spinal compression fractures. Activities in this category to avoid include sports such as golf and tennis and certain yoga poses.

Common osteoporosis medications

According to the Cleveland Clinic, for those with extremely low bone density or who have already broken a bone because of osteoporosis, medications are often used to improve bone mass and reduce the risk of future fractures. Bisphosphonates are drugs that interfere with the normal process of breaking down and reabsorbing bone tissue, thus slowing the rate at which bone mass is lost. Common drugs in this group include alendronate (Fosamax), ibandronate (Boniva), risedronate (Actonel), and zoledronic acid (Reclast). Dosing schedules can vary significantly, with some people needing to take the medications daily or weekly, while others may only need to take them once a month or once a year. Often individuals will take these drugs for three to five years and can then continue to reap benefits after they stop. Side effects include flu-like symptoms, impaired kidney function and, in rare cases, damage to the jaw bone and fractures in the femur (thighbone).

Anabolic agents (including romososumab-aqqg, teriparatide, and abaloparatide) both encourage the building of new bone and reduce the resorption of old bone. They mimic the action of parathyroid hormone, which controls calcium levels in the body. The biologic drug denosumab is a new osteoporosis medication that may be used when conventional treatments haven't worked, but it may cause dangerous side effects, including femur fracture and serious infections.

Hormone replacement therapy and osteoporosis

According to the Cleveland Clinic, because low levels of both estrogen and testosterone can negatively impact bone mass, hormone replacement therapy (HRT) is often used to combat osteoporosis. Synthetic estrogen can improve bone mass, but it's also associated with blood clots, certain types of hormone-dependent cancers, and heart disease. Because of these potential risks, estrogen is generally only prescribed to older women who also want to treat the symptoms associated with menopause. Raloxifene (Evista) is a type of drug known as an estrogen receptor modulator that has the same bone-building effects as estrogen. It's generally only used for five years.

Men with osteoporosis may be prescribed testosterone to improve their bone mass. The drug calcitonin-salmon (Fortical) is a synthetic hormone. In clinical trials, it's been shown to reduce the chance of spinal compression fractures, but it may not be as effective at decreasing risk for hip or risk fractures. It can either be injected or inhaled through the nose. It's generally not used as a first-line treatment for osteoporosis because initial research suggests it may increase cancer risk.

Not everyone agrees with the preemptive use of hormones to prevent osteoporosis. In an interview with WebMD, one researcher noted: "Since women in their 50s who do not have osteoporosis have a relatively low risk of fracture, the benefit of long-term treatment with estrogen to prevent bone loss and fractures may not exceed the risks."