Osteoporosis: what is it?

Osteoporosis is a condition where loss of bone develops to the point where our bones break easily. It is a serious condition that increases slowly as we age. Generally osteoporosis is asymptomatic (we are unaware that we have it) until there is a fall or injury resulting in a fracture. We all get osteoporosis as we age so it is important that we learn about it and try to do something to slow it down or reverse the process.

Common areas of the body where osteoporosis fractures occur:

  • the wrist - usually following a fall on the outstretched hand
  • the hip - often from slipping and twisting during a fall
  • the spine - from bending forward or heavy lifting

Bone tissue is a rigid, living structure that is constantly renewing itself. It is not an unchanging skeleton made of calcium. Microscopic holes are constantly created by bone eating cells called osteoclasts. Once these bone cavities are created, bone building cells called osteoblasts form new bone. This process rejuvenates the bone and repairs any damage.

In early childhood and adolescent years our bones grow rapidly. Good dietary calcium intake and regular exercise in these formative years are important for good bone health and peak bone mass. Bones may reach their mature length or height in the late teens but bone density and strength continue to build along with body weight and muscle strength into one's 20s and possibly 30s.

Once peak bone mass is reached, both women and men start losing bone at a rate of 0.5% to 1% loss per year. By age 60, your bone mass can have decreased by 30% compared to your bone mass at age 30. In women, the hormone estrogen contributes to the bone-building process, so as estrogen levels fall when women approach menopause, the bone loss accelerates to a rate of 2% to 3% per year. In this case, bone mass can decrease over 50% by age 60, compared to bone mass at age 30. This makes it particularly important to increase your intake of vitamin D and calcium, and explore other treatments such as with calcitonin and biophosphonates.

As we approach our later decades of life, many changing conditions make us more susceptible to fractures related to osteoporosis. The most important of these are decreased bone strength and increased risk of falls.

We are more likely to fracture a bone as we get older because of these reasons:

  • decreased bone strength due to reduced bone density
  • increased tendency to fall due to:
    • reduced muscle strength so we are less likely to break a fall
    • decreased vision, making it more likely for us to trip
    • poor balance mechanism making us more unsteady on our feet
    • posture changes resulting in center of gravity changes and more sway as we walk
    • changes in blood pressure or heart rate resulting in dizziness and unpredictable falls
    • medications that result in weakness or lightheadedness

Obviously, efforts should be made to minimize osteoporosis fractures before they happen. Physicians can identify individuals at high risk of osteoporotic fractures by doing a bone density test. It is also important to investigate whether the person is at a higher risk than normal for falling, especially if something can be done to reduce that risk.

 
John P. Wade, MD 
in association with the MediResource Clinical Team   

All material copyright MediResource Inc. 1996 – 2021. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/healthfeature/gethealthfeature/Learn-About-Osteoporosis

Osteoporosis: who gets it?

All of us will get osteoporosis if we live long enough. Since none of us have a crystal ball to predict our life expectancy, we should all do our best to ensure good strong bones and prevent falls no matter how long we live.

Osteoporosis is extremely common. It is estimated that by age 50, 1 in 4 women and 1 in 8 men will have osteoporosis. Osteoporosis causes 70% to 90% of the 30,000 hip fractures that occur every year in Canada. Men typically have a higher peak bone mass, so it takes longer for bone loss to reach a level where the bones fracture. Nevertheless, as men increasingly live past age 80, osteoporosis is going to become a more common problem for men.

Research has identified a number of risks that make it more likely for one individual over another to get osteoporosis.

If several of these risk factors apply to you, you may want to check with your doctor about how to prevent osteoporosis.

Risk factors for osteoporosis we cannot change:

  • genetics (family history)
  • female sex (osteoporosis affects women more than men)
  • age (even if we keep saying we are 39, our bone mass decreases with age)

Lifestyle risk factors for osteoporosis we can change:

  • low dietary calcium and vitamin D
  • little or no exercise
  • smoking
  • excess alcohol use (more than 4 ounces per day)
  • excessive emotional stress
  • possible excess caffeine (more than 4 cups per day)
  • excessive physical activity that results in low body weight

Medical conditions and diseases that increase risk of osteoporosis:

  • anorexia nervosa
  • renal (kidney) stones
  • thyroid disease (overactive thyroid or excess thyroid supplements)
  • cortisone or prednisone use (also high dose use of inhaled steroids for asthma)
  • anticonvulsants (seizure medications)
  • liver or kidney disease

Medical conditions in women:

  • estrogen deficiency (surgical removal of ovary)
  • early menopause (before age 46)
  • irregular periods

Medical conditions in men:

  • testosterone deficiency (gonadal or testicular failure) measured by an early morning testosterone level (blood test)

If you find that a number of these risks apply to you, you may want to think about making some simple changes in lifestyle, doing a test for osteoporosis or even starting medications that are available.

The risk factors of family history, female sex, and advancing age are powerful predictors of osteoporosis.

If you have these risks, then a bone density test can more accurately predict if osteoporosis is present.

The other risk factors for osteoporosis should be assessed as well and modified for their own sake, if possible. Each added risk factor contributes towards the suspicion of osteoporosis. One or more risk factors might be reason enough to proceed to a bone density test.

 
John P. Wade, MD 
in association with the MediResource Clinical Team   

All material copyright MediResource Inc. 1996 – 2021. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/healthfeature/gethealthfeature/Learn-About-Osteoporosis

Osteoporosis: diagnosis

Osteoporosis should be suspected in any individual who has a fracture. X-rays will usually confirm a fracture if there is one. X-rays should be done if a limb or other bone is acutely painful after a fall or injury. Sometimes individuals will have mild to severe chronic back pain, and X-rays of the thoracic or lumbar spine might detect a wedge or crush fracture (see Figure 1). Any individual with a significant fracture needs to be assessed to exclude or identify medical problems that could have played a role in the resulting fracture.

Individuals who have not had any fractures but do have a number of risk factors for osteoporosis need an examination called a bone density test to determine if osteoporosis is present.

X-ray

Figure 1

A lateral X-ray of the thoracic spine (left) might reveal small wedge fractures, or of a lumbar spine (right) might reveal a more significant crush fracture.

What is a bone density test?

A bone density test determines the bone mineral (calcium) content of certain bones. It is a simple, painless procedure that can measure the calcium content of bones in specific body areas including the spine, hip, forearm, or total body. There are several types of bone density tests available.

Several common bone density tests are available to diagnose osteoporosis
Bone density test Site checked
Single Photon absorptiometry (SPA) Forearm, heel
Dual-energy absorptiometry (DEXA) Forearm, spine, hip, total body
Ultrasound Heel

For the DEXA bone density test, for example (see Figure 2), the individual lies perfectly still on a special table while a mechanical arm passes over the body. The mechanical arm sends an X-ray beam through the bones being scanned. A detector arm below the body determines how much of the X-ray beam passes through the body and, from that measurement, calculates how much bone is present. That calculation is then compared with the average for men and women of the same sex and age. Your doctor will discuss the results of the bone density test and help you make a decision about treatment options.

bone density test

Figure 2

A common bone density test can be done quickly and in comfort.

The radiation risk is minimal - a single bone density test gives about one-tenth the radiation as a chest X-ray. This is the same radiation exposure as you receive flying from the east coast to the west coast of North America. Nevertheless, a woman should not have a test if she is pregnant.

It might be recommended to repeat a bone density test to make sure there is not further bone loss over time or to help evaluate if the treatment is effective. Generally a repeat bone density in 2 to 4 years is sufficient to see if there has been a significant change in bone density. Very occasionally a bone density after 6 months to 1 year is helpful if it is suspected that the bone loss is very rapid.

T-score

Figure 3

A T-score gives you a good idea of how strong your bones are now compared with what they were at their strongest. It does this by comparing current bone density with peak bone density. A T-score of -2 is called the fracture treshold, at which point fractures happen more often.

Who should get a bone density test to diagnose osteoporosis?

The US National Osteoporosis Foundation (NOF) has set clear guidelines on deciding who should get bone density testing. In women, it is recommended that all women over 65 or younger women with 1 or more risk factors for osteoporosis should be screened.

How do you interpret the results of a bone density test?

An individual's bone density result is compared with the average for individuals of the same age and sex. Your doctor will explain the results. Often, the result of the test is reported as a T-score. A T-score is a measure of your current bone density compared with what the density theoretically was at its peak (see Figure 3).

 
John P. Wade, MD 
in association with the MediResource Clinical Team   

All material copyright MediResource Inc. 1996 – 2021. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/healthfeature/gethealthfeature/Learn-About-Osteoporosis