Risk factors for osteoporosis
A risk factor can be defined as anything that increases your chance of getting a disease. Remember: an individual may have one or many of these risk factors and not develop osteoporosis. Conversely, many people may have no apparent risk factors and develop osteoporotic fractures.
Osteoporosis can be divided into two types: primary and secondary osteoporosis. Primary osteoporosis is the more common of the two. Secondary osteoporosis is usually the result of an identifiable agent or disease process that causes the bone loss.
Although the exact cause of primary osteoporosis isn’t always clear, a number of risk factors are known to increase the chances of developing this disease.
Certain risk factors are fixed and can’t be changed. However, you still have to be aware of them so that you can take steps to reduce bone mineral loss.
1. Fixed (non-modifiable) risk factors
Your overall risk of osteoporosis is influenced by your age, gender and ethnicity. Generally, the older you get, the greater your risk of osteoporosis.
Women are more susceptible to bone loss than men. However, even though women are more likely to sustain an osteoporotic fracture due to rapid bone loss at menopause, 1 in 5 men also get osteoporosis. In fact, some 20-25% of all hip fractures occur in older men and men are more likely to be disabled and die following a hip fracture (men tend to have more co-morbid diseases, e.g. cardiovascular disease).
Although osteoporosis is still more common in Caucasian, coloured and Asian people (possibly due to differences in bone structure and peak bone mass), a few local studies have shown that our black population have exactly the same bone density. Vertebral fractures occur at the same rate in this population group.
Ask your doctor to test you for osteoporosis if any of the following risk factors apply to you:
Genetics, along with shared lifestyle and dietary factors, will contribute to your peak bone mass and rate of bone loss at an older age. If one of your parents or grandparents has had a broken bone, especially a broken hip, you’re at higher risk of osteoporosis.
People who have already sustained an osteoporotic fracture are almost twice as likely to have a second fracture compared to people who are fracture free. Anyone who has fractured after the age of 50 years must be assessed for osteoporosis. In most cases treatment should be prescribed to prevent the high likelihood of future fractures.
Primary/secondary hypogonadism in men
Hypogonadal young men with low testosterone levels have low bone density, which can be increased through testosterone replacement therapy. At any age, acute hypogonadism, such as that resulting from orchiectomy for prostate cancer, accelerates bone loss to a similar rate as seen in menopausal women.
The bone loss following orchiectomy is rapid for several years and, in most cases, treatment should be prescribed to prevent it.
Some medications may have side effects that directly weaken bone or increase the risk of fractures due to falls. If you take any of the following medications, you should consult with your doctor about the increased risk to bone health:
- Glucocorticosteroids – oral or inhaled (e.g. for asthma, arthritis)
- Certain immune-suppressants (calmodulin/calcineurin phosphatase inhibitors)
- Excessive thyroid hormone treatment (L-Thyroxine)
- Certain steroid hormones (medroxyprogesterone acetate, luteinising hormone-releasing hormone agonists)
- Aromatase inhibitors (used in breast cancer)
- Certain antipsychotics
- Certain anticonvulsants/anti-epileptic drugs
- Proton-pump inhibitors
- Antiretroviral therapy (ART)
Postmenopausal women, and those who have had their ovaries removed or who have experienced early menopause before the age of 45 years, must be particularly vigilant about their bone health.
Rapid bone loss begins after menopause when the protective effect of oestrogen is reduced. For some women, hormone therapy may help slow down bone loss when initiated before the age of 60 years or within 10 years after menopause.
Certain medical disorders
Some diseases, as well as the medications used to treat the diseases, may weaken bone and increase the risk of fractures. Among the more common diseases and disorders that may place you at risk are:
- Rheumatoid arthritis
- Nutritional/gastrointestinal problems (e.g. Crohn’s and coeliac disease), other malabsorption diseases
- Chronic kidney disease
- Haematological disorders/malignancy (including prostate and breast cancer)
- Some inherited disorders
- Hypogonadal states (Turner syndrome, Klinefelter syndrome, amenorrhoea etc.)
- Endocrine disorders (diabetes, Cushing’s syndrome, hyperparathyroidism etc.)
There are many secondary causes for osteoporosis. Your doctor will mostly be able to detect these on the history you provide, or on the initial examination you undergo.
2. Modifiable risk factors
Here are some of the more common, modifiable risk factors for osteoporosis. This means that you can change them and reduce your risk of osteoporosis and fractures.
We all know the dangers of smoking. But many don’t know that, compared to non-smokers, people who smoke or have smoked in the past are at increased risk of any fracture. Smoking increases the risk of a hip fracture by up to 1.8 times.
Excessive alcohol consumption
People who drink more than 2 units of alcohol daily have a 40% increased risk of sustaining any osteoporotic fracture compared to people who drink only moderately, or not at all. Too much alcohol has a direct toxic effect on bone cells. Drinking in moderation will, however, benefit your overall health, not just your bones.
Low Body Mass Index (BMI)
Maintaining a healthy body weight is important too. BMI below 19 is considered underweight and a risk factor for osteoporosis. Low BMI may also result from poor nutrition and low intake of bone-healthy nutrients like calcium, protein and vitamin D.
Vitamin D deficiency
Vitamin D is made in our skin with exposure to the sun’s ultraviolet rays. This vitamin is essential for bone health in that it helps the body to absorb calcium. Few foods contain vitamin D and sunlight isn’t always a reliable source of vitamin D.
This is why vitamin D deficiency is common, particularly in the elderly, in those who don’t go outdoors, and in those who endure long, dark winters in northern latitudes.
The National Osteoporosis Foundation of South Africa (NOFSA) and the International Osteoporosis Foundation (IOF) recommend supplements for those at risk and in seniors aged 60 years or over.
Ninety percent of hip fractures occur as a result of a fall. Poor eye sight, loss of balance, neuromuscular dysfunction, dementia, immobilisation, and use of sleeping pills and anti-hypertensive medication (all relatively common in seniors) significantly increase the risk of falls and fractures.
If you’re prone to falls, you should take action by fall-proofing your home and improving your muscle strength and balance through targeted exercises.
A nutritious diet rich in calcium, protein, fruit and vegetables benefits bone and muscle health at all ages. Malnutrition in seniors is a special concern, particularly because they’re more susceptible to osteoporosis, falls and fractures.
The saying “move it or lose it” refers to the fact that inactivity results in increased bone loss. That’s why it’s important to get regular weight-bearing and muscle-strengthening exercise.
Adults with a sedentary lifestyle lose bone more rapidly, and studies have shown that sedentary older adults are more likely to have a hip fracture than those who are more active.
Eating disorders such as anorexia and bulimia that can result in extreme weight loss are dangerous for bone health. In young women this can lead to oestrogen deficiency (similar to that experienced at menopause). In these women, there’s often also a very low dietary intake of minerals like calcium, protein and other necessary key elements for bone development. The result is rapid bone mineral loss.
It’s also important to remember that eating disorders are not only limited to women and that there has been an increase of both anorexia and bulimia in young males.
Reviewed by Teréza Hough, CEO of the National Osteoporosis Foundation of South Africa: www.osteoporosis.org.za. October 2017.