Introduction

Photo of an elderly couple (PantherMedia / Andreas Marinski)

As we age, our bone density decreases. That is perfectly normal. But this decrease is greater in some people than in others. If a person’s bone density falls below a certain level, they are considered to have osteoporosis. This mostly affects older people – but certainly not all of them. The loss of bone mass starts earlier in women than in men.

Low bone density increases the risk of breaking (fracturing) bones. This can have more serious consequences in older age because broken bones do not heal as easily in older people as they do in young people. But there's still no need to worry too much about low bone density – and no reason to be less physically active. Because getting less exercise tends to increase the risk of bone fractures even more. Physical activity strengthens bones and muscles, improves your balance and prevents falls. Falls are the main cause of bone fractures in older people.

There's a lot you can do on your own to keep your bones strong. The most important thing is to stay active and eat a calcium-rich diet – and not to smoke. Whether or not it's a good idea to also take medication to strengthen your bones depends on your age and other individual risk factors for bone fractures.

Symptoms

Osteoporosis often goes undetected. But sometimes there are visible signs: For instance, your spine might start to curve slightly, making you a bit shorter. Advanced osteoporosis may result in stooped posture or what is often called a "dowager's hump" at the top of the spine. This is caused by fractures in the vertebrae that make the spine curve and may result in back pain. But many people don't even notice these fractures.

Sometimes, a painful bone fracture is the first sign of osteoporosis. Fractures typically occur in the vertebrae, wrists, ribs, upper arm bones, pelvis and hips. Some people's bones eventually become so fragile that even tripping over something or lifting a heavy shopping bag is enough to cause vertebrae to break.

Causes

Inside bones there is a supporting structure with interconnecting bony webs and rods called trabeculae. This structure is called trabecular or spongy bone because it looks a bit like a sponge or honeycomb. Osteoporosis develops when a large amount of the spongy bone tissue breaks down, leading to bigger spaces and lower bone density. How much this weakens the bones also depends on other factors, such as the detailed structure (microstructure) of the bone tissue.

 

Illustration: Healthy bone tissue (left) and fragile bone tissue due to severe osteoporosis (right) – as described in the articleBone structure: Healthy bone tissue (left) and fragile bone tissue due to severe osteoporosis (right)

Bone density increases and reaches its maximum level by age 15 in girls and age 20 in boys. After the age of 30, bone density gradually decreases. In women, this decrease happens more quickly from about the age of 50. The reason: The female sex hormone estrogen slows down bone loss up until menopause. So after menopause, when the level of this hormone drops, bone is lost more quickly.

If no other cause for the bone loss can be found, it is called primary osteoporosis. If the bones have become fragile due to another medical condition or the long-term use of certain medications, it is called secondary osteoporosis.

Risk factors

There are a number of factors that can increase someone's risk of developing osteoporosis. Some can be influenced, whereas others cannot. The main risk factors for osteoporosis include the following:

  • Older age
  • Being a female
  • Low body weight (compared to height)
  • Previous bone fracture
  • Calcium deficiency
  • Vitamin D deficiency
  • Lack of exercise
  • Other cases of osteoporosis in your family
  • Smoking
  • Drinking a lot of alcohol
  • Long-term use of steroids

Prevalence

According to the Robert Koch Institute, 3% of men and 13% of women in Germany between the ages of 60 and 69 report being diagnosed with osteoporosis. But it is not known exactly how many people actually have osteoporosis or how many bone fractures are caused by osteoporosis.

Not everyone with osteoporosis ends up with a bone fracture. Hip fractures in particular can have serious consequences. This is a problem that usually only affects older people. In Germany, 6 to 7 out of 1,000 people over the age of 65 break their hip bone (femoral neck) every year.

Diagnosis

Osteoporosis is sometimes diagnosed by accident – for instance, if an x-ray is taken of the upper body for some other reason and it shows fractured vertebrae.

Osteoporosis may also first be noticed if a bone breaks much more easily than expected, for example after falling from a standing position. If that happens, doctors can often diagnose osteoporosis based on a physical examination and a talk.

As long as no bone fractures have occurred, the osteoporosis is considered to be a risk factor for bone fractures, and not a disease. Bone density tests (bone densitometry) can be used to tell whether the bone density is low. These tests use x-rays to measure the amount of mineral salts in the bones. That can help to estimate the risk of bone fractures.

The result of the bone mineral density test is expressed as a T-score. A T-score of 0 corresponds to the bone density of a young, healthy adult between the ages of 20 and 30. The World Health Organization (WHO) currently recommends interpreting these scores as follows:

  • A T-score between 0 and -1 is normal,
  • a T-score between -1 and -2.5 is low (this is called osteopenia), and
  • a T-score lower than -2.5 means that you have osteoporosis.

A bone mineral density test alone can't reliably predict a person's risk of bone fractures. For one thing, in addition to bone density there are many other factors that play a role in bone health, such as the internal structure of the bone and the strength of the bone tissue. And the risk of bone fractures also depends on other risk factors and your overall health.

Other types of tests may be used too – for example, a blood test could be used to rule out other conditions causing the loss of bone mass.

Screening

Some doctors offer bone densitometry as an individual health care service (IGeL) to screen for osteoporosis. But there is no reason for this testing, especially in women under the age of 65 who don't have any risk factors – plus, the body is exposed to a low amount of radiation. This screening test can even be harmful if the results mean that someone does less exercise because they are worried about breaking a bone.

But tests measuring bone density may be a good idea for women who have risk factors for osteoporosis and are considering medication as treatment. In Germany, statutory health insurers will then cover the costs of the tests.

So far, there has been no high-quality research on the possible pros and cons of screening for osteoporosis in men.

Prevention

There are some things you can do on your own to strengthen your bones – like eating a diet rich in calcium, getting regular exercise and not smoking. Making sure your body has enough vitamin D is also important. In order to be able to make enough vitamin D, your body needs to get enough sunlight (UV rays).

Studies have shown that most people who also take calcium and vitamin D supplements don't benefit from them. But these supplements could increase the risk of kidney stones. Medical societies don’t usually recommend them for the prevention of bone fractures. Supplements might be a good idea for people who need nursing care and are less mobile, because they typically spend so little time out in the sun and often no longer get enough exercise.

Fractures of the femoral neck (part of the hip) are especially likely to cause serious complications: Many older people in particular often don't recover completely from those kinds of fractures. Although osteoporosis can increase the likelihood of hip fractures, falls are the greatest risk factor. So it is especially important for older people to try to prevent falls. Getting exercise can help here: Regular physical activity improves coordination and sure-footedness. Taking care of hazards around your home that could increase your chances of slipping or stumbling could also help. These may include loose cables and rugs, door thresholds and other obstacles.

Some medications may also increase the risk of falling. You can talk with your doctor to find out if you really need all of the medication that you are taking – and whether there might be any drug interactions. To prepare for the talk, you could make a list of your medication.

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Treatment

It's also important for people who already have osteoporosis to do regular exercise and get enough calcium and vitamin D.

Osteoporosis can be treated with special drugs designed to slow bone loss or increase the production of new bone tissue. Bisphosphonates are most commonly used for this purpose. Treatment with medication is only considered if someone has already broken a bone, or if their risk of bone fractures is high – for example, if their bone density is very low or if they have a combination of different risk factors for bone fractures. If you decide to have treatment with medication, doctors usually recommend taking it for several years.

It is worth carefully weighing the pros and cons of treatment with medication, especially for people who have only a slightly higher risk of bone fractures or a slightly lower bone density (osteopenia).

Hormone medications like those used to treat menopause symptoms can also lower the risk of osteoporosis-related bone fractures when taken over the long term. But long-term hormone therapy during or after menopause also increases the risk of cardiovascular diseases and breast cancer. For this reason, it's only rarely recommended as treatment for osteoporosis. Here, too, it's worth carefully considering the benefits and side effects.

A procedure known as vertebroplasty is sometimes offered to treat vertebrae fractures caused by osteoporosis. It involves injecting an artificial material called bone cement into the vertebrae. The cement then hardens. Good-quality research has shown that this treatment doesn't relieve the symptoms any better than a fake treatment (placebo) does, though. And it can have side effects. So doctors generally advise against this treatment nowadays. This also applies to a treatment called kyphoplasty – another procedure designed to stabilize vertebrae fractures. It hasn't been shown to improve the symptoms either.

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Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.

Labels: Aging and geriatric care, Bone atrophy, M42, M80, M81, Muscles, bones and joints, Osteoporosis, Prevention, Women's health