The myth of osteoporosis

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BY GILLIAN SANSON

 

When my friend Ann turned 45 she went for a bone densitometry scan. She is one of the healthiest women I know, but because she is small-framed her doctor recommended it. As she slid off the radiology table she was warned that she had "decreased bone density" and that by the time she is 80 she could be in "big trouble." Until that point, Ann had thought osteoporosis was a rare disease suffered by stooped elderly women who hadn’t had enough calcium and vitamin D when they were children. Suddenly she was worrying about falling and splintering and wondering if she should take more care when she exercised. It never occurred to Ann to question the diagnosis or to wonder why osteoporosis is now more widespread than breast cancer, AIDS and heart disease combined.

A new epidemic?
Alarming fracture statistics, persuasive advertising, and conscientious physicians are directing millions of the world’s "worried well" to osteoporosis testing and on to preventive medication. We are assured the tests are accurate and the drugs on offer are safe and effective, but we need to take a more critical look.

The statistics are certainly shocking. The Osteoporosis Society of Canada states that one in four (25%) women and one in eight men over the age of 50 has osteoporosis. The US Osteoporosis Foundation claims that half of all American citizens older than 50 will have an osteoporosis-related fracture, that at least 34 million individuals have the osteoporosis precursor "osteopenia" (low bone density), and that 20% of hip fracture victims will die within a year of the event. Yet, the Mayo Clinic says about 21% of postmenopausal women have osteoporosis and only about 16% have had a fracture, thus revealing widely diverging "absolutes" in the osteoporosis message.

A diagnosis of osteoporosis or osteopenia is a very frightening thing and there is little information available to help the consumer distinguish fact from hype before embarking on long-term drug regimes. Most of us are unaware that until it was re-defined as a measure of low bone mineral density (BMD) in 1994, osteoporosis was considered an uncommon disease of fragile bones afflicting mainly the very elderly. Everyone naturally loses bone density as they age, but the new definition does not account for that. The standard reference norm on the bone density machines is that of a young woman, making it almost impossible for an older person to have a normal diagnosis. The test categorises the disease from a single risk factor, yet it reveals nothing about the strength, micro-architecture, rate of remodelling, size or shape of bone-all factors that contribute to bone fragility.

Although extensive reviews of the evidence by independent academic organizations in Canada, the US, Sweden, Australia and the UK conclude that BMD testing does not accurately identify those people who will go on to fracture their bones, the new definition of osteoporosis as a widespread disease remains. In reality, the vast majority of the population never break their bones. Remarkably, an examination of the effectiveness of BMD screening by the University of Leeds found that people with higher bone density go on to have 63% of all fractures! All bones are designed to break when struck in a particular way. Low or high bone density makes so little difference that it is simply not worth measuring.

Most people under the age of 80 remain unaware that they have osteoporosis because it has no symptoms. Some 12% of women aged 50-79 experience spinal compression (vertebral fractures) but the majority are unaware of the fact. A small percentage do have symptoms, from which most make a full recovery. In the reassuring words of Californian osteoporosis expert Dr. Bruce Ettinger: "the osteoporosis that causes pain and disability is a very rare disease."

Debilitating hip fractures in the elderly are most likely to occur not as a result of low bone density, but because of dangerous home environments, immobility, dementia, medication such as corticosteroids, poly-pharmacy (effects of taking multiple medications), low levels of vitamin D, and existing conditions, such as hyperthyroidism, Crohn’s disease and celiac disease. In other words, the older a person is, or the more unwell they are, the greater the risk of falling and breaking a hip.

Television ads, magazine articles, and fact sheets in doctors’ waiting rooms greatly exaggerate the impact that osteoporosis can have on our lives. Even experts agree. Dr. Mark Helfand is a member of the US National Institutes of Health osteoporosis consensus panel. In his opinion, "I think even people who agree that osteoporosis is a serious health problem can still say it is being hyped. Most of what you could do to prevent osteoporosis later in life has nothing to with getting a test or taking a drug."

A new "disease"-new "treatments"
The 1994 re-definition spawned a global "osteoporosis-preventing" juggernaut involving the pharmaceutical, bone density testing, dairy and calcium industries-the issue of fragile bones largely overlooked in the push to identify and influence bone density loss. Hormone therapy (HT) was the "gold standard" treatment for decades, with its bone mineral density maintenance effects seen as a side benefit of its main purported benefits of heart disease and stroke reduction. HT is now deemed too dangerous for long-term use because of breast cancer, stroke and heart attack risks. Other osteoporosis "preventing" drugs, in particular the bisphosphonates, Fosamax and Actonel, have been available for a decade and are increasingly popular following the demise of HT. But have they in turn been properly tested for safety and effectiveness?

Bisphosphonates are a potent class of drug that suppress bone remodelling or turnover. They are known as anti-resorptive treatments because they inhibit the action of the cells that are constantly breaking down or reabsorbing old bone. The cells that re-build bone are not initially affected so there is often an increase of bone density for the first year of use, then this slows or plateaus as remodelling stops.

Sales of bisphosphonates have reached unprecedented levels worldwide. Fosamax sales have rocketed from US$1 billion in 2000 to $2.7 billion in 2003. Meanwhile, the mechanics and effects of bisphosphonates are still not fully understood and many experts warn caution in prescribing, saying that more needs to be known about the long-term effects of slowing or halting bone turnover. Although treated bone can become more dense or mineralized, when remodelling doesn’t occur, there are concerns it may become more brittle and prone to micro-fracture. Increased bone mineralization has been shown to increase micro-fracturing in animal studies. Bisphosphonates are long-acting and known to stay in the body indefinitely (in excess of 10 years), thus continuing their effect-for better or worse. It is considered unethical to study this medication in pregnant women or women who might become pregnant while the bisphosphonate is still in the bones.

Bisphosphonates can have very serious gastro-intestinal side-effects and are unpleasant to take. For all that, they offer only marginal or very modest benefit. Fosamax may reduce hip fractures by just one percent (although even this is disputed). In real terms, this means that 90 at-risk women would need to be treated for three years to prevent one hip fracture in one of them. The remaining 89 would receive no benefit. It is estimated that hundreds of women aged 50 years with low bone density would need to be treated for more than three years to prevent one hip fracture in one of the groups.

Leading osteoporosis authority Professor Ego Seeman of the University of Melbourne, Australia, poses the question:

Should we expose huge numbers of these women [age 50 and with low bone density] to a drug, its costs, inconveniences, side-effects, when most will not sustain a fracture had no treatment been given? That is, most who take the drug will be exposed to the risk of side-effects and costs and receive no benefit…This is the nature of preventive medicine; we have to treat large numbers to avert events in few. This is why the drugs we use must be safe-because most exposed do not benefit, and even a small number of adverse events can tip the balance of net benefit to net harm (www.medscape.com/viewarticle/443214).

Although a recent study showed that bone mineral density continued to increase with up to 10 years of Fosamax use, it is not clear that this means a reduction in fracture. Another recent study found that osteonecrosis (bone death) of the jaw following dental procedures is a new complication of bisphosphonate therapy. Dr. Ego Seeman warns, "We still need to answer the following question: Do drugs that suppress bone remodelling reduce or increase the risk of fracture in the long term?"

Unanticipated risks can surface long after a drug has been approved, as illustrated by the serious risks now associated with Hormone Therapy.

These days osteoporosis is no longer just a "women’s disease." But the rush to provide costly and risky medical solutions for low bone density in large populations of healthy men and women who may never suffer from the disease draws attention away from the very important issues of preventing falls in the elderly and diagnosing genuine sufferers.

Alternative approaches
For most people it seems that a reasonably nutritious diet, healthy lifestyle and regular exercise are sufficient protection against future fracture. Since her diagnosis, my friend Ann has concluded that by staying informed, and keeping healthy and fit, she is doing everything she can to avert fracture when she is older.

What you can do:

  • Educate yourself about bone health. Understand that a diagnosis of low bone density (osteopenia) or even osteoporosis is not sufficient reason to embark on a treatment regime. There are many other risk factors for osteoporosis, most importantly age, previous fracture and smoking, as well as prescription drug use such as corticosteroids and benzodiazepines. In fact, stopping drugs that increase risk of falls such as sedatives and hypnotics is likely a safer and more effective strategy than adding a drug that simply increases bone density. Your doctor can test you for secondary causes of osteoporosis.
  • Make sure your diet covers the diverse nutritional needs of bone. Including calcium, magnesium, vitamin K, boron, manganese, zinc, copper, silicon and other nutrients is ideal. Fresh vegetables, fruits, nuts and seeds are good sources of these nutrients. Limit heavy protein and salt intake, reduce alcohol, don’t smoke, and for essential vitamin D, get sunlight on your skin at safe times of the day. Note: too much supplemental calcium can be harmful and there is inadequate evidence that dairy foods protect against fracture.
  • Exercise often! The force of muscles pulling against bone stimulates bone remodelling and formation. Higher impact activities like running, jumping and jogging are very effective, but regular aerobic exercise such as walking is also beneficial. Weight bearing exercises, resistance training, and flexibility and balancing exercises like Pilates, Tai Chi and yoga are also important. Research has demonstrated that we can benefit from exercise at any age-even centenarians will experience an increase in strength, stamina and muscle mass. Exercise programs have been found to reduce the frequency of falls in high-risk older people.
  • Don’t rush into taking drugs that may influence bone density but at present have little known benefit in terms of reducing fractures.

Gillian Sanson is the author of The Myth of Osteoporosis (MCD Century Publications 2003).

For more information visit her website at www.gilliansanson.com