The Burden of the BONZ report
February 3, 2008 by Gillian Sanson
A staggering 84,354 New Zealanders are predicted to break bones this year as a result of osteoporosis; that’s one osteoporosis related fracture every six minutes and a hip fracture every two hours. By 2020 the annual osteoporosis-related fracture rates are expected to exceed 115,000. So cautions the Fonterra funded ‘Burden of Osteoporosis in New Zealand Report’ commissioned by Osteoporosis New Zealand. But should we really heed the exhortations to drink more milk, scoff calcium supplements, have our bones scanned or swallow powerful drugs?
Osteoporosis day (October 21 2007) saw extensive media coverage of the ‘Burden of Osteoporosis in New Zealand (BONZ) Report’ released in Dubai at an international osteoporosis conference. New Zealand took centre stage with its report which, says Osteoporosis NZ (ONZ) executive director Julia Gallagher, heralds ‘the alarming spread and incidence of osteoporosis’, described as having devastating consequences for individuals and their families, and an impact greater than colorectal, breast and prostate cancers. Menopausal women who have had a fracture and have a low calcium diet are identified as the population most at risk, and ONZ is calling for government funded bone density scans for all such women. Given its authoritative claims, you would expect the BONZ Report to be based on a long-awaited analysis of our country’s own fracture statistics, and robust science. It is most puzzling to find the report is, in fact, generated from formulae adopted from a six year old Swedish study whereby the incidence of hip fractures is used as a basis from which to estimate the incidence of all other types of fractures: rib, vertebrae, clavicle, scapula, tibia, fibula, scapula, sternum, forearm, pelvis or proximal humerus. [i]
Unlike most other fractures hip fractures require hospitalisation and are generally well recorded, Some 2,500 hip fractures occur annually in New Zealand in men and women of all ethnicities aged 49 to 90 plus years. The BONZ report conveniently assumes all hip fractures, regardless of how they occur and at what age they occur, to be osteoporotic (the result of fragile bones or a low trauma event), and all fractures extrapolated from them have the same definition of fragility. Swedish-determined ratios are then applied. For example, osteoporotic hip fractures represent an estimated 3.8 percent in women aged 50 -54 years. From this figure, fractures of the vertebrae in the age group are calculated to be 15.1 percent. Thus 17 hip fractures convert to 865 vertebral fractures. By applying the various ratios to every age group and to every bone, 2500 hip fractures translate into 84,354 presumed total fractures.
Some startling rates emerge. Men aged 50 – 59 ( a known low-risk group) are calculated to have 75 hip fractures, 2,688 vertebral fractures, and 4,060 rib fractures this year – all as a result of osteoporosis. And women aged 50 -59, similarly at low risk, are predicted to have 58 hip fractures and a total of 6,298 other osteoporotic fractures. Where are all these people? And how is it possible to extrapolate fracture incidence from one type of fracture to another?The authors of the report acknowledge it is not known whether it is valid to use the Swedish study to determine New Zealand fracture incidence, or whether this can be done across ethnicity and time. Regardless, the report is condensed into a press release by Osteoporosis NZ that has all the appearance and authority of concrete facts born of rigorous scientific analysis of local data. It is then faithfully reported by an uncritical media.
For many years our osteoporosis authorities have claimed New Zealand has the highest osteoporosis-related fracture rates in the world, yet we have never done a study to measure the actual incidence of fragility fracture. Fracture statistics in Western countries are widely divergent and hotly debated. It is easy to make the rates of osteoporosis fractures high by including accidents and high impact breaks, and by including fractures in all bones – not just those known to be associated with osteoporosis-type fractures, typically the hip wrist and vertebrae. Interestingly, as New Zealand braces itself for an apparent epidemic, there are reports of a decline in fracture rates in other parts of the world.[ii] Hip fracture incidence has been dropping in parts of the US and Canada, and has fallen dramatically in the last decade in Finland.[iii] [iv]
Osteoporosis New Zealand is urging women over 50 who have had a fragility fracture to have bone density testing and consider potential treatment. Just how fragility fractures are determined and recorded is anyone’s guess – once you are over 50 it seems few questions are asked. All bones are designed to break when struck in a particular way. If the Auckland University authors of the BONZ report sweepingly assume all hip fractures from age 49 are osteoporotic, how can we expect our regular doctors to make the distinction?
Everyone loses bone density as a consequence of aging. . It has been well established that a diagnosis of osteoporosis based on low bone density is not a good predictor of future fracture, and that the majority of fractures occur in people with normal to high bone density. Women may find themselves candidates for long term bisphosphonate drug treatment with its attendant risks and side-effects when their actual risk of fragility fracture is very low.
Osteoporosis is not a killer disease. Although traumatic at the time, bone fractures heal remarkably well in most cases – even those associated with painful vertebral compression. Just how Osteoporosis New Zealand calculates osteoporosis to be more impacting than bowel, pancreatic, and breast cancer is a mystery. In reality few deaths can be directly attributed to fracture. Although hip fractures are very serious events in the elderly, most subsequent deaths occur as a result of prior chronic illness that has contributed to the hip fracture and to the patient’s decline.
When characterised by bones that fracture easily, osteoporosis is not a common disease. It is linked most often to serious chronic conditions afflicting a small percentage of the population; and to prescription drugs such as corticosteroids commonly prescribed for rheumatoid arthritis, asthma, and other conditions. Up to 50 percent of patients using these drugs may fracture, especially postmenopausal women.
Nightly television advertisement exhort women to drink more milk and quaff calcium supplements but there is insufficient evidence to prove dairy consumption is beneficial to bone or that it will prevent fracture. A recent analysis of six large prospective trials involving 40,000 men and women found that a low intake of calcium was not associated with a significantly increased risk of any fracture – osteoporotic or otherwise.[v] The benefits to bone of calcium supplementation are also debated and emerging serious risks now make them an unwise choice. A five year Auckland University study was recently halted upon finding that supplementing with 1000mg of calcium a day increased the incidence of heart attack by 40 percent in women over 70 years. Regardless, TV ads urge women to take a form of calcium supplying 1200 mg a day.
For the vast majority a diet favouring fresh leafy green vegetables, nuts and seeds; a healthy lifestyle; and regular aerobic and weight bearing exercise will be sufficient protection against future fracture. Campaigns to steer well individuals into costly screening and risky medical solutions draw attention away from the very important issue of preventing falls. Falls are responsible for 90 percent of hip fractures in the elderly, and addressing risk factors such as environmental hazards, poly-pharmacy, visual difficulties, and immobility are far more effective ways to prevent fractures than having a test or taking a drug.
Media reporting and direct-to-consumer advertising compound the confusion and misinformation and serve to alarm and confuse consumers. Faithful reproduction of press releases without the effort to dig a little deeper and uncover cleverly orchestrated marketing hype gives unwarranted credibility to questionable science and breathtaking assumptions. Doctors are also subjected to and influenced by industry-funded public awareness campaigns alongside advertising targeting them. There is little doubt that the number of bone scans and prescriptions for bisphosphonate drugs have risen considerably since the launch of the BONZ report with its associated media coverage and advertising campaigns.
People seeking guidance from the ‘consumer advocacy’ organisation Osteoporosis NZ will be no better informed. Consumers trust their advocates are independent and expect that they will provide accurate unbiased independent information to enable them to make informed decisions. However this is an organisation with close ties to a powerful industry which many New Zealanders see as part of the backbone of our country. This report – which is a collaboration between them - is designed to frighten politicians into funding and supporting them both. It also serves to alarm and frighten consumers and does little to provide useful advice or help those at genuine risk of osteoporosis.
