Around 100 pulmonary physicians have spoken up in a paper and questioned the scientific basis for the limit values on particulate matter and nitrogen oxide which form the legal basis for the (planned) driving bans for diesel vehicles in urban centers. These objections have been eagerly received by politicians and industry and have led to a lively public discussion in which all sides refer to scientific studies – which are not always comprehensible to the layman. Suitbert Cechura clarifies some aspects of this lesson in medicine as a science and its role in society.
Particulate matter and nitrogen oxide
Prof. Dr. Dieter Köhler, the best known critic of the limit values, former president of the German Society for Pulmunology and long-time head of a pulmonary clinic, attacks not only the scientific basis of the limit values, but also the thesis of harmful particulate matter in general: “You say that particulate matter is harmless? – Not in itself. In Mumbai, for example, we sometimes come up with 800 micrograms per cubic meter of particulate matter from all kinds of sources, and that strains the lungs of course. As with all toxins, particulates also depend on quantity.” (Interview with Köhler, Cicero Online, 10.11.2018) Aside from the fact that the interviewer didn’t notice that it has to mean “per cubic meter of air,” the lung expert is noticeably inaccurate. Particulates are not all the same. As a scientist, the man must know that toxicity is depends not only on quantity, but also on quality. Particulate matter is defined by its size or smallness. And this is not simply an arbitrary consensus that was established one day. The smallness of size has medical significance. Particulate matter also has different chemical compositions, many of which are toxic. Combustion processes such as cars, power stations or heating systems essentially produce the same toxins as cigarettes, the toxicity of which nobody wants to question. Their constituents are known in detail and also their effect on the human body.
Coarser dusts can be filtered out by the cilia in the bronchi and can lead, if too much strain is placed on it, to inflammation or damage to the bronchi, including the lungs; in the past, this became noticeable in regions such as the Ruhr, in for example pseudo-croup and other respiratory diseases among children. The coarser dust has in many cases disappeared, continued or even intensified in particulate matter. It can’t be filtered by the cilia, it reaches not only the lungs, but is able to penetrate the alveoli, the blood vessels and the cells. This causes harm to the blood vessels, inflammation and damage, as well as deposits of blood lipids in the vessel walls. Cardiovascular diseases with heart attacks and strokes are the consequences. Since the particles can penetrate into the cells, they also interfere with their reproduction and have an effect on the dividing of DNA. If this process is disrupted, cell dysfunction is the consequence, and growths can occur – i.e., cancer. All this is not just a question of the dose or the amount of the toxin.
Nitrogen oxide is an irritant gas and attacks the mucous membranes. The level at which this poison is concentrated in the air therefore plays an important role. If it is highly diluted, it will hardly have a damaging effect; however, this does not lessen the fact that when it is more concentrated it irritates the mucous membranes of children, the sick, or the elderly, and others later. Therefore, as little of this gas as possible should be in the air. However, nitrogen oxide does not usually occur in isolation, but mostly in combination with particulate matter or other harmful gases. Therefore, the amount of nitrogen oxide is also taken as an indicator of strain with harmful influences on the human body. Such an approach abandons strict rules for direct evidence of damage, because an indicator does not detect the processes themselves, but selects a factor that should serve as a clue to presumed processes. Whether this presumption is stringent depends on the underlying explanations or inquiries. If nitrogen oxide is detectable in street traffic together with other substances and their sizes vary with the size of nitrogen oxide, then such an assumption is justified. If due to its size and chemical composition particulate matter and nitrogen oxide, in concentrations that occur in street traffic, cause health damage, then it would be consistent to use everything technically feasible to avoid this damage. However, this is not the position of politics, nor is it the position of medicine. This is reflected in the position of the guidelines of the Society for Pulmonology Specialists, against which the criticism of the 100 doctors is directed.
Standard of care guidelines
The existence of standard of care guidelines already refers to the status of medicine, which is not simply a department of the natural sciences. Although medicine is largely based on scientific findings from the fields of biology, chemistry and physics, it is in no way limited to these fields. For this reason, the results of medicine are not always verified scientific knowledge. There are also epidemiological studies, which are also part of medicine, or therapy control, which, like epidemiology, argues with statistical results, i.e. with probability statements that of course do not represent explanations of causes. Standard of care guidelines should provide recommendations for treatment by physicians and information for patients as well as reflect the state of medical research. They result from the requirement for “evidence-based medicine,” i.e. that all medical treatment should be based on scientific findings. A strange requirement! As a layman, one assumes that physicians do this as a matter of course. The requirement was directed against the previously applied practice in which physicians obtained their knowledge from their education, but then did not necessarily have to continue educating themselves – a shortcoming which the legislators addressed with an obligation to continued education. This counts as a gold standard, i.e. a criterion that cannot always be achieved and implemented. Diagnostics or therapies which are based on scientific findings are thus not rejected, but placed in the rank of second place.
This makes it firm and clear that it is more important in medicine to examine what works for humans in terms of injury or cure, and less important why and how something works. This becomes an argument when therapies are used that produce an effect without there being an explanation as to why they work or should work, such as acupuncture or electroconvulsive therapy in psychiatry. Medicine thus proves to be a practical science comparable to engineering, which is based on natural science but wants to translate it into practical technology. Medicine therefore often uses technology or includes craftsmanship such as surgery or dentistry.
Epidemiology
Epidemiology is an integral part of medicine. It compiles statistics on the incidence and distribution of diseases or deaths in relation to the total population and individual groups of people. In this way, medicine obtains information on possible sources or causes of illness. Statistical results, however, cannot lead to an explanation of the cause; they investigate the combined occurrence of events in the form of correlations or extended statistical procedures which are partly based on correlations: It is often argued that people who exercise are healthier than those who do not. One can cite corresponding results. But the whole thing can also be read the other way around: exercise is mainly practiced by those who feel healthy and not by those who consider themselves physically handicapped. The correlative result can be taken from both. Correlative connections therefore require clarification as to why events occur together; without this clarification, nonsensical results can also appear statistically significant. In this context, reference is often made to the decline in the population of storks and the simultaneous decline in the birth rate, which proves to be statistically above accidental, but of course does not prove that storks bring children.
However, epidemiology is not only used to identify possible causes or manifestations of disease. Studies on the state of the population are also carried out for policy-makers who want to get an idea of the state of the population’s health – after all, this forms the basis of state power, which is why the ability of people to function is an important piece of information. This does not, of course, mean that everyone within the nation must be healthy; only a sufficient number of healthy people are needed who are able to fulfill their function as employees, mothers, soldiers, lawyers, etc. Medicine as a practical science not only serves the healing of people – even though it is often stylized as a profession that is solely oriented towards this purpose – but also fulfills other tasks and places itself at the service of very different purposes: Even the family doctor is a healer, a businessman, and at the same time a state representative who decides on the ability to work and thus either stops patients from fulfilling their employment contract obligations or frees them from them.
Clinical studies
Medicine is concerned with systematically testing the effects of its own actions on people. The simplest form is to get an idea of the starting point and the result of the treatment. The key question is: Was the therapy successful? This form of examination has a defect; the healing could also have been done by the body itself, without any intervention from outside, because every body has self-healing powers. Thus it is often stated that time is the greatest “ally” of the doctor, which, however, is not always true.
The aim of clinical studies is to investigate whether the effect of a treatment can be distinguished positively from the effect of self-healing forces. For this purpose, randomized clinical double-blind studies are carried out as far as possible. Randomized means: The participants in the study are randomly divided into a control group and a study group. This distribution is intended to ensure that the groups do not differ significantly in composition and that the result is not influenced by the different preconditions of the participants. Whether the random distribution really causes an equal composition of the groups would actually have to be tested, but such an examination does not always take place.
The participants of both groups should not know to which group they belong, hence the term blind study. The control group receives a so-called placebo, a sham drug or a sham treatment. The therapy group receives the therapy whose effect is to be investigated. In order to eliminate the participants' expectations about the treatment that might influence the outcome, the individuals are kept in the dark. If you assume that you are receiving a positive treatment, you are more like to mobilize self-healing forces – the so-called placebo effect! The treating physicians should also not know, as far as possible, who among the participants is receiving the drug or the sham drug, because their expectation about the success of the treatment could also influence the result. These are the requirements for a clinical trial, but they cannot always be met.
The results of the groups are then statistically compared to determine whether the difference, e.g. treatment results, was accidental or over-accidental. The efficacy of a treatment can thus be checked. However, the efficacy of treatment does not say anything about the cause of the disease, although this is sometimes argued in medicine. The administration of serotonin, for example, may improve the mood of depressives, but to conclude that serotonin deficiency is the cause of depression would be anything but a true explanation. Nobody would come up with the idea of concluding from the successful treatment with antibiotics that inflammation would be caused by an antibiotic deficiency in the body.
The available studies
Although this form of research can only provide hints of causal relationships, it plays a prominent role in medical science, which is also reflected in a guideline on the effect of particulate matter: “The current knowledge on the relationship between adult mortality and long-term exposure to particulate matter is based on four American and two European cohort studies... The largest and most important is the study by the American Cancer Society, in which the risk factors and the time and cause of death of the cohort were linked with emission data from up to 156 US conurbations... The cohort comprised 500,000 men and women, the observation period was from 1982 to 1998. For lung cancer mortality, the relative risk for PM 2.5 [particulate matter of 2.5 micrometers] was statistically significantly increased.” (S3 Guideline Prevention, Diagnosis, Treatment and Aftercare of Lung Carcinoma, Long Version 1.0 February 2018, AMWF Registration Number 020/007OL, p. 42/43)
The guideline does not argue with the nature of particulate matter and its chemical composition, but with its effect on humans, in terms of the extent to which damage manifests itself in the population. This of course is something other than explaining the effect of a substance on the human body. In principle, it takes the viewpoint of public health, i.e. damage only becomes significant when it affects a lot of people. Nobody would make the determination of the cause of a flu caused by viruses dependent on whether or not lots of people get sick. Apparently, however, with modern lifestyle diseases, it is not sufficient for doctors to identify the cause of a disease – such as cardiovascular diseases, cancer, diseases of the musculoskeletal system, asthma, allergies, chronic respiratory diseases or psychological disorders.
For them, the various causes, such as toxins in the air, in food, etc., which can be individually determined in their effect, are not sufficient reasons for a disease, but only possible causes of disease, because – this is the argument – not everyone who comes into contact with them gets sick and not in the same way. In doing so, doctors refer to the fact that since poisons or radiation do not occur in isolation, it is hardly possible in individual cases to determine which of the many pollutants caused the disease. So all pollutants count only as possible causes or risk factors. This is a way of viewing things that is never put into practice with bacterial or viral diseases, although – as is well known – the presence of viruses or bacteria and contact with them does not always and in all cases lead to the outbreak of the disease.
Although the effect of prolonged stress, poisoning, radiation, etc. is known, this is never recorded as an unambiguous cause of illness, but always only as a possible one; the relevant cause-and-effect relationship is considered to be inseparable from others and thus can’t be unambiguously identified. In this respect, medicine also fulfills an ideological function: if the causes of disease cannot be clearly determined, then there is also no clear scientific guideline for the policy-makers to prevent damage to human health.
The fact that the relevant specialist societies also rely on statistical data makes them vulnerable, since the critics know the difference between a scientific explanation and a statistical study. They use this difference to attack the thesis of harmful particulate matter. For their part, they refer to statistical studies on the influence of diet, smoking and exercise on diseases, but they do not question the conditional validity of the determination of causation in an interesting way. Of course, it also proves advantageous to them that there are innumerable conflicting studies. Medical research is owed to not only the scientific interests of specialists who want to heal people. It also takes place on behalf of state and economic institutions, with the consequence that the interests of these institutions are asserted in research. Today, a significant amount of medical research is financed by the pharmaceutical industry, which wants to develop new drugs and bring them to the market. As a result, positive research results, which are intended to prove the efficacy of the drug, are published, negative results are not. So the professional journals already convey a skewed picture of the state of the science. The participating researchers are also advertising vehicles for the drugs they are researching, by holding expert lectures on their research at congresses and thus promoting them for use to their colleagues.
Statistics offers researchers a range of possibilities to influence the results. When it comes to epidemiological research, the decisive question is: which factor is related to the outbreak of a disease? Place of residence, particulate matter, diet, sex or eye color? According to this question, a more or less pronounced connection can then be identified that can be tested for significance. In clinical trials, it depends on the selection of participants in the study or on the questions: How are those who discontinue participation rated? If they are removed, then the probability of a positive result increases; if they are evaluated as negative, the effect is reversed. The question of what is considered a positive result also plays a role. When is the effect of a blood pressure lowering agent considered a success? How strong must the reduction be and in what period of time? Shortly after the treatment, permanently or should the effect also be shown in a reduced rate of heart attacks in the subsequent period? These are only some of the possibilities available to researchers to influence the result.
Not only the pharmaceutical industry finances health research, but also the auto industry. German car manufacturers, for example, set up a research institute, based on the model of the tobacco industry, that is supposed to counter research results that give a negative picture of the effects of car traffic with their own research results, in order to question the effects determined by other parties. The institute was known for experiments on monkeys, which were systematically exposed to exhaust fumes. That led to the outcry: poisoning animals – that can’t be done!
The fact that research also takes place at state universities for the pharmaceutical industry and for other branches of industry is something that politicians want. They have commissioned the universities to raise as much third-party funds for research as possible, i.e. to conduct as much research as possible on behalf of business or government agencies. In job contract negotiations, therefore, one of the criteria for selection is how much research funds the applicant has managed to raise outside the university for his or her research over his or her scientific career.
The critics from the Association of Pulmonology Physicians of course know the state of their science and take advantage of all these contradictions and shortcomings in order question the harmfulness of particulate matter and nitrogen oxide in general as well as the limit values related to them and demand their scientific review.
Limit values
Limit values reflect two assumptions: first, that the substance in question is harmful; second, that a dose can be determined at which the harmfulness no longer exists. Reference is often made to Paracelsus, who said that every substance is a poison, as it just depends on the dose. However, the statement has only a very limited justification. Paracelsus is right, because even harmless water, drunk in large quantities, can have a harmful effect when, for example, vital minerals are washed out of the body by extreme consumption. The ancient sage in his statements referred to acute poisonings, because he had no knowledge of the effect of different substances in the body. Nitrite, for example, is not toxic, but in the body nitrite is converted by digestion into nitrosamines, which are harmful. So the harmfulness of a substance also depends on how it is absorbed by the body – via the skin, the lungs or the digestive tract; what changes it undergoes in the body; and whether it is excreted again. Heavy metals do not cause poisoning in small quantities, but they are not excreted, accumulating mainly in the fat tissue. So, in the long run, an increase in dosage takes place in the body. Some substances penetrate the cells and negatively influence them or are even harmful to cell control via DNA; here there can be no dose that would be harmless.
The majority of chemical substances used in the production, processing or shipping of goods have never been tested for their effect on humans, and the EU initiative to make up for this has not only been blocked by Germany and limited to new products, with the review also being left to manufacturers, similar to the car industry’s exhaust review. Limit values are only brought into the discussion or ordered where the harmful effect of a substance is known. Then estimates are made as to how great the damage in the population will be, depending on the dosage. If studies are available on how disease rates and deaths differ between urban and rural regions, for example, depending on the degree of exposure to particulate matter, then a measure can be found – namely for a projection that states how many people get ill or die when exposure to particulate matter in the air increases or decreases.
The criticism of the pulmonary specialists is directed against this form of demonstration. It is not a scientific investigation, it is only an extrapolation, a lot of statistics. The content of the calculation is the scandal. Such an extrapolation calculates with the sick and the dead. It is not the point of view that humanity should be protected from damage as far as possible. Rather, the leading question is how much health damage in the population one wants to accept. However, this is not a scientific question, but a political decision. It is not reached by expert committees, which only have an advisory function and provide the basis for the political decision, which apparently calculates with cases of illness and death, because it is aware of other criteria that justify accepting them.
The reasons are known: The use of poison should not be a burden on business life. Equipment for cleaning exhaust gases from cars, heating systems or power stations make products or energy more expensive. This may limit a company’s sales or profits. After all, all politicians agree on one point: economic growth is a must; the wealth of those who invest in the economy should grow, because everything in society depends on it. And this criterion is more important than the health of the population, whose functioning should, however, not be unduly impaired; therefore it is necessary to limit the damage. Limits are thus always a compromise between the profit demands of the economy and the need to protect the population. Both sides should be taken into account, which have their cycles. Sometimes limits are tightened, because everyone is needed when business is buzzing; then the economy must be relieved again when each one is not needed in recession times.
The critics accuse the politicians of setting the limit values arbitrarily. They point to the different limit values in each country as well as to the differences applied to street traffic and to the workplace. The differences are a method. In determining limit values, the governments of the different countries reflect on their economy and population, applying sometimes stricter, sometimes less strict standards. In order to spare its economy, the German state imposes more poison on employees at work than on people in street traffic, which includes children, who as the nation’s young require more consideration.
Medicine contributes to this by making it look like the limits have a scientific character, even though its studies do not provide proof as to when a substance is harmless; its projections can only show what damage is likely to be caused by how much toxin. In this respect, the critics are right when they question the scientific nature of the limit values; but they do not do this in order to protect citizens from damage, but to question all limitations to damage.
For their criticism, the minority of pulmonary physicians have been accused of being bought by industry or by interest groups and of doing their handiwork The accusation misses the point, as most physicians see themselves as being socially responsible. And that means nothing other than that they see themselves called upon to make their contribution to the most diverse national issues – whether this is palliative medicine to make dying easier for people, in euthanasia or in executions, where doctors administer the lethal injection, examine the effect of the gas or the electric chair, because they want to help enforce the law. Concern for the health of the population also has its two sides: the healing of those who suffer from the consequences of viruses, bacteria or “civilization,” i.e. everyday capitalistic life, or the examination of the damage caused by the stresses and strains, and the test of what humans can endure without immediately becoming sick or dying. Without such research, no limit values can be determined, tortures are ineffective, and one or the other option disappears during war. In this respect, Auschwitz as a research center was not a slip-up. Doctors have always met all these demands. Criticism therefore depends on the purposes to which physicians make themselves available and for which they use their scientific and statistical knowledge.
With their criticism that the research on limit values has neglected the effects of lifestyles on those investigated, the critics of limit values show themselves to be in tune with the times and basically in agreement with those they criticize. After all, there is widespread public agreement that the individual’s state of health is essentially determined by his or her behavior, whether he or she smokes, drinks alcohol, eats healthily or exercises. Because if people in this society have to endure a lot of damage, then it is not appropriate to cause additional damage to oneself by smoking and drinking. In addition, one needs a steeled body in order to be able to cope with the stresses of daily work life and the detrimental impact on the air and food. Healthy nutrition and exercise should make people invulnerable – as a universal remedy against disease. How did a leading German politician of the past, when “resilience” was not yet heard of, demand of his young: they should be as tough as leather, as hard as Krupp steel, and as fast as a greyhound. Apparently, not much has changed.
Comments
Post a Comment