It's not your genes, stupid.

Imagine traveling back in time and meeting your caveman ancestor of 10,000 years ago. Imagine telling him about what life is like today: that, with the tap of a finger you turn darkness into light, a cold room into a warm one and a tube in the wall of your cave into a spring of hot and cold water. You tell him...

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To hell with exercise

Who says that exercise is medicine? For one, the American College of Sports Medicine (ACSM) of which I'm a professional member. Then, how can I say it isn't?

Let's look first at the conventional view of the benefits of exercise. There is a large and increasing amount of evidence which clearly tells us that exercise prevents today's number 1 killer: cardiovascular disease. That is, heart attack, stroke and peripheral vascular disease. Mind you, what is common knowledge today emerged only some 50 years ago when Morris and colleagues discovered that UK bus conductors, the guys climbing up and down the double-decker London buses, had better fitness and fewer heart attacks than their all-day-seated driver colleagues [1].

In the years since then our knowledge about the effects of physical activity on cardiovascular, metabolic and mental health has virtually exploded. From this evidence the U.S. Dept. of Health and Human Services (HHS) concluded in 2008 that the most active people of the population have a 35% reduced risk of dying from cardiovascular disease compared to the least active people [2]. The WHO lists insufficient physical activity (PA) as the 4th leading cause of death world wide after high blood pressure, tobacco use and high blood glucose. What's wrong with this picture? High blood pressure and high blood glucose are known consequences of a sedentary lifestyle. So is obesity, which ranks 5th place on the WHO killer list. Which is why physical inactivity deserves top spot on that list.

What most people don't know is the way lack of physical activity causes all those diseases, from insulin resistance and diabetes to arterial dysfunction and atherosclerosis, and from there to heart attack, stroke, kidney failure. The mechanisms are extremely complex, and, while we have untangled quite some of them, there are probably a lot more to discover. I'll try to make this the subject of one of the next blog posts. 

Now you are probably asking yourself, how the hell, with all this evidence, will I ever be able to make my point that physical activity is not a medicine. Ok, here it comes: it's a matter of viewpoint. The one I'm taking is the one of evolutionary biology. Let me play its advocate and present as evidence a couple of insights.

First, our human ancestors, who had roamed this Earth as hunter/gatherers for the most part of human existence, had, by necessity, a much more physically active lifestyle. A lifestyle which required at least 1.7 to 2 times the normal resting energy expenditure [3]. [To get an idea about resting energy expenditure and physical activity levels and how they are calculated, simply follow the links to the videos.] Those ancestors' genes are what we have inherited. And these genes are exposed to a lifestyle which is vastly different from the ones under which these genes evolved. Specifically with a view to physical activity, which brings me to evidence no 2:

What we typically observe today are physical activity levels with factors of somewhere between 1.2 and 1.4 of our resting energy expenditure. That's true for most people.

Even if you were to follow the ACSM's recommendation of 30 minutes of moderate to vigorous exercise on at least 5 days per week, would you NOT reach the level of 1.7 if you are working in a typical office job or doing house work. Which means, the physical activity levels which we recommend today, do not add a behavioral type of medicine into our lives, they merely reduce the extent of a "poisonous" behavior called sedentism. It's like cutting down from 2 packs of cigarettes per day to 1 pack. Would you call this a "medicine"? Would the ACSM call that a medicine? With respect to exercise they do.

So, OK, if you had been attracted to this post in the hope of finding some excuse for not doing exercise, or some argument to get those exercise evangelists, like myself, off your back, I'm sorry to have disappointed you. No, actually, I'm not sorry. And neither will you be, if you get your physical activity level above those 1.7. Then you may just start calling exercise a medicine. Until then, chances are you will still go to hell with exercise, because you get too little of it. Certainly too little to stay out of that hell of heart disease, stroke, diabetes and many cancers.

1.           Morris, J.N. and P.A. Raffle, Coronary heart disease in transport workers; a progress report. Br J Ind Med, 1954. 11(4): p. 260-4.

2.           Physical Activity Guidelines Advisory Committee, Physical Activity Guidelines Advisory Committee Report, 2008, U.S. Department of Health and Human Services: Washington, D.C.

3.           Eaton, S.B. and S.B. Eaton, An evolutionary perspective on human physical activity: implications for health. Comp Biochem Physiol A Mol Integr Physiol, 2003. 136(1): p. 153-9.

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MORRIS JN, & RAFFLE PA (1954). Coronary heart disease in transport workers; a progress report. British journal of industrial medicine, 11 (4), 260-4 PMID: 13208943
Eaton, S., & Eaton, S. (2003). An evolutionary perspective on human physical activity: implications for health Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, 136 (1), 153-159 DOI: 10.1016/S1095-6433(03)00208-3 PrintPDF

Screw Your Health?!

So, what's your excuse for not exercising enough, for smoking, for not watching your diet, for getting fatter every year, and therefore having high blood pressure, and too much glucose and cholesterol in your blood?

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Chronisch gesund geht doch!

In meinem vorangegangenen Beitrag habe ich erläutert, wie unser Gesundheitswesen dem Ziel der chronischen Gesundheit im Wege steht. Wie dieses Ziel erreichbar ist, ist Gegenstand meines heutigen Beitrags.

Gesundheit als shareholder value.

Anfang diesen Jahres drohte die Ratingagentur Standard & Poor's den G20 Nationen mit einer Herabstufung ihrer Ratings beginnend in 2015. Der Grund: Die bestehenden Gesundheits- und Rentensysteme werden unter der Krankheitskostenlast einer zunehmend älter, kränker und dementer werdenden Bevölkerung zusammenbrechen. Und damit das Wirtschaftswachstum ausbremsen.

Warum ist dieser Schuss vor den Bug so wichtig? Weil hier ausgesprochen wird, was schon lange hätte erkannt werden sollen: Gesundheit ist nicht nur das vielzitierte hohe Gut. Sie ist ein Wirtschaftsgut.

Ihre Gesundheit macht Sie produktiver für Ihren Arbeitgeber und profitabler für Ihre Krankenkasse und Ihren Lebensversicherer. Sobald Ihre Gesundheit im Universum des Shareholder Value auftaucht, haben Ihr Arbeitgeber, Ihre Kasse und Ihre Lebensversicherung auch finanzielle Anreize, in Ihre Gesundheit zu investieren. Und einen Anreiz, den Return-on-Investment mit Ihnen zu teilen. Im Rahmen einer Gesundheitsdividende, die Sie für Ihre Gesundheitsbemühungen belohnt. Das Schlüsselwort heißt Anreize. Fehlende Anreize sind der Grund für das Versagen der Präventionsbemühungen unseres Gesundheitswesens.

Egal ob Geld oder Anerkennung oder was auch immer Ihren Nachbarn grün vor Neid werden lässt, die treibende Kraft hinter allem menschlichen Handeln sind Anreize. Sie sind als Triebfeder unseres Handelns in unsere Hirne programmiert. In der programmiersprache des hyperbolic discounting. Wenn uns dieses Phänomen etwas gelehrt hat, dann ist es die Notwendigkeit von Anreizen, mit denen wir jene ausstechen können, die uns zu ungesundem Verhalten verführen.

Was hält unsere Firmen davon zurück, die Gesundheit ihrer Beschäftigten  massiv mit Anreizen zu fördern? Sicherlich nicht die Geringschätzung ihrer Beschäftigten. Und selten die Unberechenbarkeit des Return on Prevention. Meistens liegt es am Fehlen eines Werkzeugs, das es ermöglicht, Belohnung an jene zu verteilen, die es verdienen, und jenen vorzuenthalten, die nichts für ihre Gesundheit tun. Mit Yoga- und Betriebsportgruppen gelingt das sicherlich nicht. Dass solch ein Werkzeug im Rahmen betrieblicher Gesundheitsförderung funktioniert stellen wir gerade unter Beweis. Wir haben dieses Werkzeug entwickelt um damit auch die zweite und dritte Strategie zu realisieren.

Den eigenen Kopf überlisten

Wenn's ums Esesn geht lässt sich der Affe in uns kaum von dem kontrollieren, was uns zum Menschen macht: Vernunft und freier Wille. Aber egal ob Mensch oder Affe, Mutter Natur hat uns die Gabe des impliziten Lernens gegeben. Mit ihr lernen wir komplexe Aufgaben zu meistern ohne erklären zu können, wie wir das schaffen. Denken Sie ans Schwimmen oder ans Radfahren. Dies sind Beispiele für einen 6. Sinn, mit dem wir unser Verhalten präzise so steuern, dass wir weder ertrinken noch vom Rad stürzen. Warum nicht auch unser Essverhalten?  Mit einem 6. Sinn für die tägliche Kalorienbilanz schaffen Sie zwar nicht die Lust auf das Tiramisu aus der Welt, aber er hilft Ihnen zu erkennen, welche Maßnahmen notwendig sind, um Ihre Kalorienbilanz heute auf dem Kurs zu halten, mit dem Sie planmäßig Ihr Gewichtsziel erreichen. Dass es funktioniert haben wir in unserem Labor getestet. Die Idee dazu kam uns im Rahmen einer klinischen Studie, in der wir testeten, wie wir jenen Menschen zur chronischen Gesundheit verhelfen können, die am stärksten gefährdet sind: Übergewichtigen und Adipösen. Unser Probanden, die diesen 6. Sinn entwickelten, nahmen ab und hallten ihr Gewicht noch heute.     

Nun stellen Sie sich wahrscheinlich die Frage: Selbst wenn mein Arbeitgeber mir die notwendigen Anreize gibt, wie kann ich sicher sein, dass mein geändertes Bewegungs- und Ernährungsverhalten mir auch tatsächlich die chronische Gesundheit beschert? Womit wir beim letzten Punkt angekommen sind:

Die Biomedizin weiß was wirkt

Die Biomedizin kennt keine wirksamere Intervention zur Verhütung von Herzinfarkt, Schlaganfall und Diabetes als zielgerichtete Bewegung und Ernährung. Mit dieser Strategie reduzierten die Probanden des Diabetes Prevention Program das Risiko, Diabetes zu entwickeln um rund 60%. Jene Probanden die statt einer Lebensstiländerung das Medikament Metformin einnahmen, schafften nur halb so viel, 30% Risikoreduzierung.

Dass Bewegung das Risiko an chronischen Krankheiten zu sterben um 40% reduzieren kann, ist aus großen Studien bekannt. Damit ist Bewegung in ausreichender Intensität, Dauer und Häufigkeit die wirksamste Strategie zur Verhütung dieser Erkrankungen.  Auch vieler Krebserkrankungen, darunter Darmkrebs, Prostatakrebs und Brustkrebs.  Unser Gesundheitssystem aber verschleudert das Potenzial dieser Strategie, denn es ist auf die Behandlung von Krankheit ausgerichtet, nicht auf den Erhalt der Gesundheit. Solange keine Risikofaktoren messbar sind, bleiben wir aber unter dem präventiven Radar dieses Systems. So lange bis es zu spät ist. Denn wer als Mann mit 45 Jahren noch frei von Risikofaktoren ist, hat eine 97%ige Chance seinen 80 Geburtstag bei guter Gesundheit zu feiern. Liegen bereits 2 Risikofaktoren vor, wie beispielsweise Bluthochdruck und erhöhtes Cholesterin, dann schrumpft diese Chance auf 50%. Und selbst wenn Sie zu jener glücklichen Hälfte zählen, die die 80 Kerzen auf dem Kuchen ausblasen darf, werden Sie genau das wahrscheinlich nicht mehr schaffen, denn eine der chronischen Krankheiten wird Ihnen die Kraft dazu genommen haben.

Die gute Nachricht: mit den einfachen Gesundheitsverhalten - nicht rauchen, ausreichende Bewegung und kein Übergewicht - können Sie heute schon bestimmen, wie Ihre 80. Geburtstagsparty ablaufen wird.

Die schlechte Nachricht: Das alles sind keine neuen Erkenntnisse. Den Kassen sind sie genau so bekannt wie den Wissenschaftlern, die sie erarbeiten. Dass Präventionsbemühungen trotzdem nicht von den Kassen finanziert werden, hat erstaunlicherweise nichts mit Geiz oder Unvernunft zu tun, sondern mit dem Paragraphen 20 des fünften Sozialgesetzbuchs. Dort schreibt unser Gesetzgeber den Kassen eine Ausgabengrenze für Prävention vor: € 2,84 pro Versichertem pro Jahr. Offensichtlich sind die Bekenntnisse unserer Gesundheitsminister zur Prävention nichts anderes als Lippenbekenntnisse.

Es sind also nicht Defizite in Wissen oder Fortschritt, die uns das Zeitalter der chronischen Gesundheit und Langlebigkeit vorenthalten. Es ist das Versagen unseres Gesundheitssystems, das Wissen einzusetzen und damit die Gesundheit endlich als das zu behandeln was sie ist, ein Wirtschaftsfaktor. Ist das nun wirklich eine so radikale Änderung der Strategie unseres Gesundheitswesens?    PrintPDF

Am I shittin' you? Learn to be a skeptic!

Learn to be a skeptic!

Why you cannot believe what you read about medical studies.

In my last blog post I promised to tell you why you shouldn't trust any study results, particularly when you didn't read the study yourself. It has to do with the methods of biomedical research. To make my point, I'll take the gold standard research method, the double blinded randomized controlled trial, or RCT. 

Let's say we want to test a drug, which is supposed to lower blood pressure in those who suffer from hypertension. The researchers have decided to enroll, say, 100 "subjects". That's what we typically call the people who are kind enough to play guinea pig in our studies.   

The researchers will first do a randomization of subjects into one of two groups (very often it is more than one group, but to keep it simple we will assume just two groups). What we mean with randomization is that we randomly assign each subject to one of the two groups. One group - the intervention group - will receive the drug, the other group - the control group - won't. What they get instead is a sugar pill, a placebo. 

With the randomization we want to make sure that, at the start, or baseline, both groups are indistinguishable from each other with respect to their average vital parameters. For example, if we were to calculate the mean age, blood pressure and any other variable for each group, these mean values would be not different between groups. That's important, because we want to isolate the effect of the drug. We don't want to worry at the end whether the effect, or lack thereof, was maybe due to some significant difference between the groups at baseline. 

Once the randomization is done, we organize the trial in such a way that neither the "subjects" nor their physicians and nurses know whether they get the placebo or the active drug. Both sides are blind to what they get and give, which is why this set-up is called double-blinded. That's an important feature, because a researcher often goes into a study with a certain expectation of its outcome. Either that outcome supports his hypothesis, or it doesn't. To eliminate the risk of, more or less subconsciously, influencing the study towards a desired outcome, double-blinding is very effective tool.

Fast forward to the end of our trial. We have now all the data in hand to compare the two groups. After unblinding, the researchers will compare the two groups with each other. In our example, they will compare the average, or mean, of the blood pressure values of all the individuals for each group. If the intervention group's mean value is lower than that of the control group, then it is plausible to reject the null-hypothesis, that is to REJECT the idea that the drug is NOT as ineffective as the placebo (we are, of course, assuming here that the sugar pill didn't lower the blood pressure of the control group). 

There are statistical tools to determine whether the difference between the groups may just be a chance event, or whether chance is a very unlikely explanation. We can never rule out chance completely. Now, when we are confident that it is the drug and not pure chance, which has lowered the mean blood pressure in the intervention group, we write our paper to present it in one of the medical journals. 

If the subject is a little more sexy, than just lowering blood pressure, there will sure be some journalists who pick it up and report to their readers that, say, eating chocolate makes you slimmer. I'm not kidding. This headline very conveniently went through the media shortly before Easter this year [1]. Good for Hershey who are running it of course on their webpage. And in the media it reads like it did in the Irish Times: "Good news for chocoholics this Easter. Medical Matters: No need for guilt over all those Easter eggs."    

I'm not going to comment on the media geniuses, because it's their job to put an angle on every story, so that YOU find it interesting and read their stuff. But since I'm sure you'll follow these links, just let me warn you: the chocolate study was an observational study, not an RCT. And one thing we MUST NOT do with the results of observational studies is to confuse association with causation. Only when we conduct an RCT, where the intervention group eats chocolate and the control group doesn't, might we be able to determine whether there is a causal link. And for obvious reasons we can't blind the subjects, to whether they eat chocolate or not. But I'm digressing.

Back to our blood pressure study. When we compare the group averages, everything looks very convincing. And sure enough, as researchers we are happy with the results, and we are perfectly correct, when we conclude, that this medicine does its job. 

But will it do it for you? When you are hypertensive? You might be wrong if you say "Yes". And you will be wrong more often than we, as researchers, or your doctors care to admit. For one simple reason: The variability of effect within the group. You give 50 people the same drug, and I bet with you, and I'm not the betting type, that you'll have 50 different results. 

The mean value of the entire group glosses over these inter-individual differences. Let me give you an example from a study performed on 35 overweight men, who were studied in a supervised and carefully calculated 12-weeks exercise program, with the intention of reducing body weight. The mean weight loss was 3.7 kg. That was almost exactly the amount of weight loss which the researchers had expected from the additional energy expenditure of the exercise program. But when they looked at each individual, it became clear that the group mean doesn't tell you anything about how YOU would fare in that program. 

First of all, the standard deviation was 3.6 kg. Now, a standard deviation of 3.6 kg simply tells you that approximately two thirds of the participants experienced a weight loss anywhere between 3,7 kg (the mean) minus 3.6 kg and 3.7kg + 3.6 kg, that is between 0.1 kg and 7.3 kg! That's a lot of kilos. And what about the remaining one third of those participants? They are even further from these values. In this case the greatest loser went down by 14 kg, and the biggest "winner" gained almost 2 kg. A spread of 16 kilos!

Here is the graph which shows you the change on body weight and fat for each individual participant. Which one would you be?

This effect is what you do not see when you don't read the studies. And in most studies, it isn't made obvious either. 

Which is why, you shouldn't be surprised to learn that most major drugs are effective only in 25-60% of their users [2]. The same goes for weight loss drugs and interventions, for almost everything we study in biomedicine. 

That's not a problem for us in public health. Because a drug, which works in 60% of the patients, helps us reduce the burden of disease in our population. Public health is not interested whether you are one of the 60% or not. But you are. And that's why I believe not only medicine, but also prevention must be individualized.

 Which is why the GPS to chronic health, which I currently develop, is all about helping you find your individual path to your health objectives.

Why not have a look at it, and maybe even try it out? 

References

1.           Golomb, B.A., S. Koperski, and H.L. White, Association Between More Frequent Chocolate Consumption and Lower Body Mass Index. Archives of Internal Medicine, 2012. 172(6): p. 519-521.

2.           Wilkinson, G.R., Drug Metabolism and Variability among Patients in Drug Response. N Engl J Med, 2005. 352(21): p. 2211-2221.

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