Georg Ivanovas From Autism to Humanism - systems theory in medicine

4.6. Second-order cybernetics in medicine

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c) osteoporosis and the drug paradigm

A more practical example is osteoporosis. The term, “literally ‘bone porosity’, designates a deficiency of bone tissue per unit of bone as organ” (Beeson/McDermot 1975: 1826). It is one of the most expensive diseases in our time.

There has been a sharp increase of osteoporosis in the Western world from 1950-1980 with a clear difference between city and countryside and between different countries (Cummings/ Melton 2002). Concerning its causes, epidemiological data are quite confusing and all sorts of theories prevail. Of course, there is a genetic theory (the 20p12 gene and the BMP2 gene might play a role) but the findings are not very convincing (Styrkasrdottir et al 2003).

Some decades ago osteoporosis was a diagnosis of an advanced situation because it only could be diagnosed through fractures or x-ray, which is altered only if the bone has lost a lot of its density. This situation changed with x-ray absorptiometry which is able to provide more general data on bone mineral density (BMD). Through its introduction osteoporosis became a widespread disease. The diagnosis depends mainly on the measurement as there are no satisfactory clinical means to assess bone quality (Kanis 2002).

The diagnosis of osteoporosis is established according to WHO principles modified by the International Osteoporosis Foundation (Kanis 2002). Its basis is the so-called SD score. The SD score expresses bone density values of individuals in relation to a reference population in standard deviation (SD). The current classification is:

But bone density measurement is not sufficient to assess bone quality (Seeman/Delmas 2006) or to preview fractures accurately (Jeras 1999). This is why there is a lot of discussion concerning this diagnosis and many prefer to talk about fracture risk.

This leads to a confusing situation: the measurement does not lead to a suitable diagnosis and what is discussed about has often little to do with the diagnosis and the measurement. A look at the risk factors for osteoporotic fractures shows why:


female sex,

primary or secondary amenorrhoea,

primary or secondary hypogonadism in men,

Asian or white origin, previous fragility fracture,

low bone mineral density,

glucocorticoid therapy,

high bone turnover,

family history of hip fracture,

poor visual acuity,

low bodyweight, neuromuscular disorders,

cigarette smoking,

excessive alcohol consumption,

long-term immobilisation,

low dietary calcium intake,

Vitamin D deficiency

(Kanis 2002).

age,

history of maternal hip fracture,

increase in weight since age of 25 years,

height at age 25 years,

self related health,

previous hyperthyroidism,

current use of long acting benzodiazepines,

anticonvulsant drugs,

caffeïn intake,

walking exercise,

inability from rising from a chair,

perception,

resting pulse rate,

any fracture since age of 50 years,

calcarean bone density

(Cummings/Melton 2002).


Thus, osteoporosis turns out to be only one of many risk factors for fractures and the tendency to suffer fractures could be seen as a life style problem, as well (Keen 1999).

Pathophysiologically, osteoporosis is an imbalance between osteoblasts and osteoclasts, where even the brain function plays a role (Hebrew University 2005). Osteoporosis is a network pathology (chap. 6.2, 6.7) with a rigid regulation of bone metabolism (Gerok 1989). But reductionist science investigates often only one of the components, for example, the osteoblasts (Ducy et al 2000) or the osteoclasts (Teitelbaum 2000). And treatment tries often to fix one of these components. This lead to two major setbacks in the history of the disease.

  1. Around 1980 - 1990 the standard therapy was sodium fluoride (NaF). It was known that NaF stimulates osteoblasts to produce more bone mass, thus improving BMD. Every week we (as GPs) received a new (mainly industry sponsored) study, proving the effectiveness of this therapy. After some years an independent study showed that, in fact, bone mass was higher but as well the incidences of extra vertebral fractures (Riggs et al 1990). Through the therapy bone mass had increased, but the bone became more brittle. NaF is not used anymore. This is a typical example how the treatment of a surrogate parameter leads to a decline of health (chap. 2.5.f)
  2. Later, to prevent the post menopausal decline of BMD, hormone replacement therapy (HRT) was widely used. The results were again favourable. Even the largest study (WHI study) proved a decrease in hip fractures (5/10 000). However, these women had a quite greater risk for heart attacks (7/10 000), stroke (8/10 000), breast cancer (8/10 000) and thrombosis (18/10 000) (Wassertheil-Smoller et al 2003).

The current treatment of osteoporosis is bisphosphonate. There are first indications that the therapy might lead to an increase of osteonecrosis (Rizzoli 2008) and atrial fibrillation (Group Health Cooperative Centre for Health Studies 2008). Although there is no sharp rise of this complication, nobody knows what will happen when millions of women take the drug for decades.

Given all that, the question of the appropriate therapy is difficult to decide on. To prevent hip-fractures (what is the main aim) many strategies are possible. As falling is the central cause (Oliver et al 2005), so called hip-protectors have been found to be helpful (Meyer et al 2003), but are controversially discussed (Parker et al 2006). Good sight is also essential to avoid falling. This would improve the situation without even touching any mechanism of osteoporosis.

Prevention of osteoporosis and/or fractures is possible in many other ways: exercise, nutrition, restriction of drugs and stimulants etc (Platen 1997). Especially exercise is effective (Kemmler el al 2004).

As also serotonin fosters bone formation (Kolata 2008) and even the autonomous nervous system influences (via leptin) the remodelling of the bone (Elefteriou et al 2005), it is evident that bone density and quality is very much an expression of the general condition of the human and less a local problem. That implies that also general methods of relaxation and well-being might be effective in the prevention of osteoporosis and fractures.

Looking at all these possibilities it is not intelligible why mainly drug therapy is discussed in the medical discourse. Or better: it is only intelligible when a machine based diagnose and a drug based intervention is taken as general guideline for medical treatment.

What creates such a kind of perception and action? What maintains it? These are important questions in a second-order analysis. It is not necessary to solve them. This is a first order thought. Second order cybernetics has to provide the necessary tools to improve the understanding of such interactions, what, eventually, might result in an increase of choices.


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