How do I know if I have osteoporosis?
Since most people do not know they have osteoporosis until they break a bone, it is often very difficult to diagnose. Since there are few symptoms, it’s a good idea to monitor certain risk factors (see below). However, the only way to be sure is to measure the bone mineral density with a DXA scan (Dual-energy X-ray Absorptiometry).
Commonly known as a bone density test, the DXA measures the density of a man's bones compared with the bone density of an average young adult of the same gender and ethnicity. The DXA scan uses a small amount of radiation to measure the density of the bones in the spine and hip. The test gives a 'T score', which tells the doctor whether or not bone loss has happened. The patient's bone density is then classified into three categories based on the T score: normal, low bone density, or osteoporosis. Osteoporosis may also be described as severe osteoporosis based on the T score in combination with fracture.
The recently published FRAX™ tool calculates the 10-year risk of hip fracture, or of any fracture related to osteoporosis, based on the patient’s risk factors, with or without a bone mineral density measurement. Once physicians develop experience in using this tool, and more data is accumulated, it is likely that it will become an important way of determining who should have a bone mineral density measurement, and for guiding treatment. Not all physicians are using the FRAX™ calculator yet, but it is increasingly becoming part of the osteoporosis detection procedure.
What do the results of a bone mineral density test mean?
A man who has a T score of -2.5 or less has osteoporosis, is at high risk of getting a bone fracture and should consider treatment. A score between -1.0 and -2.5 shows low bone density and may mean that some lifestyle changes are needed to reduce the risk of developing further bone problems. It is worth noting that Osteoporosis Canada now recommends that a T-score of –1.0 to –2.5 in a man over 50 years old be described simply as “reduced bone mineral density” rather than being called osteoporosis. In men less than 50 years old, as in younger women, Z-scores are recommended rather than T-scores, and a Z-score greater than –2.0 is considered “within the expected range for age” while a score of less than –2.0 is “below the expected range for age”.
Osteoporosis Canada recommends the following persons should have a bone density test:
- those aged 65 or older
- those who have lost 4 or more cm in height overall, or 2 or more cm in one year
- anyone with kyphosis—a hump or excessive curvature of the back
- patients taking long-term glucocorticoid medication (a drug usually given to treat arthritis, asthma or kidney diseases)
- anyone with a history of fractures in which osteoporosis is suspected
- persons already diagnosed with osteoporosis should also use the bone mineral density test for monitoring purposes
Other reasons (“risk factors”) why men should consider a bone density test:
- a low body mass index (less than 20)
- a parental history of hip fracture
- current smoker
- excessive alcohol intake (>3 drinks per day)
- testosterone deficiency
- rheumatoid arthritis
- chronic kidney and liver disease
- an overactive thyroid
- consumption of anti-convulsive drugs
- inflammatory forms of arthritis
- malabsorption from the intestines
- high urine calcium levels
While each of these risk factors increase the chances of a fracture minimally, some have a greater impact on bone health than others.
