Monday, December 31, 2007

Best of 2007

I conclude this year with an overview of what I have found to be the most interesting or intriguing facts and opinions about really good news, body weight and obesity, the drawback of weight concerns, passive smoking, lies, damned lies, and statistics, and much more.

My first post, back in April, was about a study failing to report an effect of garlic on cholesterol. Today I would comment a bit differently on it, but the fact that I have started with a skeptic issue is quite illustrative of how this blog has developed from beginning to now.

Enjoy your life, enjoy your food

egg Isn't it a bit strange that mainstream health news are full of stories about the "big killers" while a new report tells us that Americans never have been as healthy as today? We know why. Bad news is good news for the media, that's why every finding that "food X promotes cancer" is multiplied over and over but we never hear the good news such as "food Y does not promote cancer". I think it is high time to steer in the opposite direction. I have come across some research news recently that may counter false worries about food: Enjoy your sunny side up egg, leg of lamb fat or sweet cookies because it will not harm your heart. White sugar, even for diabetics, is no taboo at all (but of course they should monitor their blood sugar levels). Fear of excess body weight is the source of most food concerns, but it seems that you should not worry adding pounds when getting elderly. This brings me to another big issue on Med Journal Watch.

Body weight and obesity

body weight When I started my blog, I was convinced that overweight and obesity is bad for health and that any skepticism on this issue is denialism paid by the fast food industry. Today, after having looked at a lot of facts, I doubt

  1. that a body mass index of more than 25 is bad for all people regardless of gender, age and health status,
  2. that body fat is an important cause of disease,
  3. and that weight loss promotes health and can be achieved by most people in the long run.
August 2nd, 2007 was the day when I changed my mind. Two months earlier I already had come across a surprising outcome of a study showing that obese fit men live longer than those of normal weight. I admit that I did nor really trust this study, but it caused me to look for odd findings about obesity and health. And this is what I have found: Slim heart patients die faster, body mass helps elderly asthmatics to survive, and puzzling contradictory news about body fat and breast cancer. See also my interview with Linda Bacon on weight and health.

The drawback of weight concerns

weight concerns While the health benefit of weight loss remains to be proven and the advice of weight loss advocates is sometimes absurd, there are many unhealthy side effects of weight concerns: Fear of fat makes kids sick, weight concerns may be bad for your fitness, distressed victims of the war on obesity, yet pregnant women have been the target of weight loss hysteria, dieting messages have adverse effects, and weight control has been linked to youth suicide.

Passive smoking

passive smoking When looking at passive smoking with the same critical view as in the obesity issue, can I still uphold my view that secondhand smoke makes people sick and kills them? In order to check this I did some math which supported my view. A second point is the fact that the victim of secondhand smoke is being harmed against his or her own will which must be weighted stronger than bad consequences of own behaviour. And, finally, I performed a direct comparison of evidence for the risk factors body fat and passive smoking, using the theme of a boxing match.

I have started reporting passive smoking study results as early as in April, for instance about impotence and bladder cancer, parental smoking, and a post series about the dangers of secondhand smoke: part one, two, three.

Lies, damned lies, and statistics

daphnia The art of lying with statistics is using correct numbers but shifting their weight until we get a picture that is completely different from what the original numbers have shown. You also may call it the strategy of selling molehills as mountains. I often have come across this strategy during my research. Another source of false claims is publication bias, also called cherry-picking of results. And when scientists and reporters jump from results to conclusions, yet another source of error lures behind: the so-called post hoc fallacy, the wrong belief that the first event is the cause of a second event if they always follow each other. For instance in a Danish study on the cost of obesity. Correlation may or may not imply a cause. I have discussed this important issue, regarding storks and babies, fat, smoke, and cancer cells.

Reserves against loss of body and mind

old fit Given that most people lose weight before they die, a weight benefit in old age is no surprise. We all must die, but a body mass reserve seems to delay the final slimming down. When it comes to mental fitness, a similar mechanism is at work: cognitive reserve. For instance, an intellectually demanding job is a life insurance for brain cells. But body and mind always go together. Therefore you may even jog your brain fit and prevent frailty to stay mentally fit.

Heart issues

heart One of my evergreens with a daily readership is this piece about the fact that chest pain is not a safe sign of heart attack in women. Another difference between male and female hearts is the meaning of heart rate. Test yourself: Do you know the warning signs and risk factors of a heart attack? Alcohol has been told to be good for the heart but this is not true if you smoke. And for heart patients, red wine may work as well as statin, but with more pleasure. And keep listening to your partner, for heart's sake. This brings us to the next subject.

Sex, love, partnership

sex and love Do you know why men report more sex partners than women? Do you know that first sex not only very early but also very late may cause sexual problems? Did you know that love is in the genes when it comes to style? Or shall I tell you something about sleep sex that goes far beyond wet dreams?

Useless remedies, quackery, and placebo effect

placebo pill I have reported study findings about useless vitamin supplements, valerian drops, selenium, and Bach flowers. Read more about the placebo effect in my three-part series, beginning with the statement that the term itself is misleading and that there is no such effect in the strict sense, the second one is a pragmatic view, asking how to make best use of it, and finally I come to the conclusion that if such an effect exists it must be the power of mind.

Religion and altie medicine

pigeon Both share some common features, for instance operating with beliefs outside of scientific reasoning. I have looked for mechanisms that may help to explain the evolution of such beliefs and the fact that they have survived against all evidence of disproving facts. One such mechanism may be random reward, and a mechanism by which rats survive poison. In the case of religion, I have dealt with the raw material in human behaviour from which religion may have evolved. Do you believe in God? If you do, you must do so against logic reasoning because proofs of God do not work.

Hosted blog carnivals

Last but not least, I have hosted four blog carnivals in the past year:
Photo credits:
Wellcome Library

Saturday, December 29, 2007

A lot of bias and possibly some reality

picking lucky clover
A sample of twenty medical studies shows three times more significant results than null findings which gives me the strong impression that selective picking and publishing of results is the cause rather than real links between factors relevant to health.

During the holidays, I am taking a few days off from blogging, and I have used some of this time to think about what I am doing here. One big challenge for anyone reporting medical research findings is John Ioannidis' landmark essay, published two years ago at PLoS Medicine: "Why most published research findings are false". He gives a number of reasons and uses a bunch of math to prove them, and I must admit that I cannot follow the math. But the logic is convincing. Ioannidis comes to the following conclusion:

"There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field. In this framework, a research finding is less likely to be true when the studies conducted in a field are smaller; when effect sizes are smaller; when there is a greater number and lesser preselection of tested relationships; where there is greater flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial and other interest and prejudice; and when more teams are involved in a scientific field in chase of statistical significance. Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias. In this essay, I discuss the implications of these problems for the conduct and interpretation of research."
Let's suppose a field of research where there are no associations at all. The level of significance, by generally accepted convention, is 5 percent - the probability that an association has been detected where in reality there is none. That is, for every hundred trials we are likely to see five associations where there is none. This would be no problem as long as every finding, be it positive or null, would have the same chance of being published. But “something found" is much more likely to be published than “nothing found". And with this publication bias, false findings are more likely to be published than true findings.

In search of publication bias

Yesterday I have taken a look into this matter. Of course it is not a scientific research but I try to be as accurate as possible. I did a Medline search with the terms "nhanes association mortality diet" in order to find studies that link various diet factors to diseases and mortality. I only included original studies (no meta analysis), and I limited my search to twenty publications. I have found that significant results strongly outnumber the non-significant ones by a factor of about three:
  • 9 non-significant findings where all but one are presented together with significant findings in subgroups or different associations,
  • 26 significant findings.
For instance, potassium intake is not linked to stroke mortality in most people but to a lower stroke mortality in hypertensive men. This is a clear example of publication bias: The finding in the hypertensive subgroup has been published because it has been found significant, it would not have been published if non-significant, just as the non-significant finding in hypertensive women has been omitted in this study.

According to Ioannidis, the relationship between true and not true results is 1:1 in a well-powered randomized controlled trial in a well explored scientific field. In epidemiologic studies like the twenty I have selected, this relationship is only 1:10. The relationship between published significant and non-significant findings is 3:1 where it is expected to be 1:10, hence I have found a publication bias of 30. In other words, a significant finding may be up to 30 times more likely to be published than a non-significant one. This concludes my own little research. Let's turn to some more conclusions of Ioannidis.

Less power, more false results

Picking and publishing subgroup results increases the rate of false results not only by publication bias but also by weakening the statistical power. A subgroup of cases is always smaller than the whole group, and by laws of statistics the fault rate must increase.

How many results may be true?

Ioannidis has calculated the percentage of study results that are likely to be true. This is the case only for a well-powered randomized controlled trial with little bias and 1:1 odds that a true result may be found, or for a meta-analysis of good randomized controlled trials where results have to be confirmed. In both cases, the results are 85 percent likely to be true.

Single epidemiological studies that are done for testing a hypothesis (e.g. about fat intake and heart disease) will be true only in 20 percent of the cases, even if well done. A meta-analysis of small, inconclusive studies is still less likely (41 percent) to be true than false.

Photo credit:

Thursday, December 27, 2007

Health Blog Carnival Watch 1:14

Grand Rounds
4:14 at Medgadget
4:13 at Trick-Cycling For Beginners
4:12 at Odysseys of George
4:11 at Med Help

Pediatric Grand Rounds
2:12 at Hope for Pandora

Skeptics' Circle
#76 at Aardvarchaeology
#75 at Pro-Science

Gene Genie
#22 at Sandwalk

Tuesday, December 25, 2007

Messing around with proofs of God

Robert Spaemann
If they are proofs in the strict sense then they must fail due to circular reasoning, and if they comply with the laws of logic then they are not proofs but simple definitions. Just look at this one, given by Robert Spaemann, chief philosopher of the Vatican: "Truth exists, therefore God exists." I have come across this "proof" yesterday in a newspaper interview with Spaemann. It is a classical example of begging the question: The premise assumes that God is a prerequisite of truth. We see that thruth exists. The conclusion that God exists has already been set as a premise which is a logical fallacy. In other words, Spaemann assumes that God exists. Then he says he is ready to answer the question whether God exists or not exists. He begs that question in order to "prove" that God exists.

Just the same with Anselm of Canterbury's ontological proof: "God is the greatest being that can be conceived. The idea that God exists is possible. If we imagine a God existing only in our minds and a God that exists in reality, the latter will always be conceived greater than the former. Thus, the greatest possible God is the one that exists in reality. Therefore, God must exist." Again, we see a premise that God is the greatest being that can be conceived. Then we are told that it is possible to conceive such a greatest being. The conclusion is the same as the premise: a greatest being.

I admit that I cannot follow all the logical and mathematical steps in the so-called "proofs of God". It somehow reminds me of these math tricks where you have to guess a number, then follow a set of mathematical operations given by the presenter and then he will tell you the number you have guessed. You do not see at first sight that the trick formula is constructed in a way that it puts out exactly what has been put in.

Muddling around with definitions

Another group of so-called "proofs" are no more than definitions. For instance, the following cosmological argument: "The Universe has begun with the Big Bang. Big Bang has happened in reality. Every event must have at least one cause. So there must be a cause that has made Big Bang happen and that has brought the Universe into existence. This cause must be greater than anything we can conceive. It must be God."

So far so good. I can agree with every word of the above statement, I only have to look very closely at the last word. If the above is a stand-alone statement and does not refer to any religion, it can be viewed as a definition of God: God is the entity that has fueled Big Bang, maybe it is the Energy per se, and as such a part of the whole Universe. This definition will lead to a sort of pantheism. I am a bit hesitant in using the word God for the Big Bang causing entity, because this entity has nothing to do with the following ideas:

  • a “consciousness" or "intelligence" of the entity,
  • the likelihood that resurrection from the death has ever occurred or will ever occur,
  • an immortal soul,
  • behaviour of human beings being judged by the entity,
  • the entity as source of the holy scriptures,
  • etc.
Selective pressure

In my humble opinion, the question of God is not a matter of cosmology or astrophysics but of human psychology and the way our brain works. Religion is a coping mechanism that has evolved with our brain, and its main function may be to overcome cognitive dissonance. One such dissonance is the confrontation with our own death. As long as we are alive we see that the Universe exists, and it is just impossible that it should not exist. After our death, from our point of view, the Universe will disappear because we no longer will be able to perceive it. But in reality, the Universe will continue to exist. This contradiction is hard to stand, thus our brain must find solutions to cope. One such solution may be believing in an immortal soul who still will be able to perceive the Universe.

My first post about the evolution of religion deals with some of the raw materials that build up religious behaviour: Dreaming as an everyday experience of a "second world" and the behaviour of children who, when scared, search the protection of their powerful parents.

Photo credit: Wikipedia

Monday, December 24, 2007

Sweet and heart go together well

christmas cookies
Enjoy your Christmas cookies, and if some of them are heart shaped, you may take this for a symbol of a recent study result from Sweden. A possible association of sugar intake and mortality of heart patients has been assessed in more than four thousand established cases, and it came out that there is no such association.

This is good news for all who have heard all those sayings of sugar being bad for health. There is no reason for worries, at least when it comes to the heart. One of the things you can forget, for instance, is the glycemic index. The higher this index is, the faster is the uptake of sugar into the blood. No problem for the heart, the Swedish study says. Nor is the amount of sugar going to the blood, the glycemic load, of any importance for the heart.

Photo credit:

Friday, December 21, 2007

Smoking weakens the nerves

enschede disaster
Think twice before lighting up in order to cope with stress because, in contrast, nerves will get more vulnerable. Just look at this exhausted firefighter at the Enschede fireworks disaster of May 13, 2000, having a cigarette break. More than sixty of his rescue worker colleagues have been examined soon after the disaster and again eighteen months later. It came out that smoking predicts posttraumatic stress disorders among rescue workers involved in the disaster: Those who smoked were more affected by fear of intrusions, avoidance, hostility, and depression than the non-smokers. These symptoms are typical for the posttraumatic stress disorder.

The sense of relief that comes along with a cigarette is just as deceptive as the sense of warmth that comes along with alcohol in the cold. The well-being is an illusion in both cases. In reality, the nerves get weaker and the body cools down. In the worst cases we see nervous breakdowns and deaths from cold.

Photo credit: Netherlands Institute for Health Services Research

Thursday, December 20, 2007

Demanding job as a life insurance for brain cells

stock exchange
Jobs with high intellectual demands are protective against dementia in old age, and this benefit is strongest in persons with a lower intelligence. It seems that this is one of the rare cases where he that has plenty of goods shall not have more. The magic word is "cognitive reserve", and it once more has been found to explain facts in a study on job demands, intelligence, and cognitive performance of men in late life.

More than a thousand U. S. men, IQ tested as young soldiers, have later been contacted as World War II veterans in old age. In a special telephone interview, their cognitive status and their job history have been assessed. Every job has been analyzed for intellectual demand, for level of human interaction and communication, for physical activity and for visual attention. It came out that high intellectual job demands and intense human communication are both independently linked to a higher mental performance in old age. In contrast, a physically demanding job is linked to a lower performance. And very interestingly, the greatest benefits of a demanding job have been found in those with the lowest IQ results in young age.

This result strongly supports the concept of cognitive reserve. Those with high intellectual abilities in young age already have plenty of reserve, and a demanding job will not add very much. But those who start at a lower intellectual level have the chance to build up a substantial amount by using their brains.

Photo credit:

Wednesday, December 19, 2007

Sleeping beauty, slimming beauty

sleeping beauty
If you are fat, the worst thing you can do is having stress and sleepless nights from weight concerns and diet plans. And the best thing, according to a Korean study on sleep and obesity, may be just to relax and take it easy, having a good and long bout of sleep every night.

More than six thousand Koreans have been surveyed about their sleep duration, and their body mass indices (BMI) have been measured. It came out that the long sleepers tend to be slimmer than the short sleepers. Other studies in Iowa, Maryland, and in the NHANES survey have come to the same result.

This is not only a correlation but a causal link. The mechanism has been identified: Sleep increases the level of the satiety hormone leptin and decreases the level of the appetite hormone ghrelin.

Photo credit:

Tuesday, December 18, 2007

Enjoy your leg of lamb fat

leg of lamb
A new study refutes health concerns about trans fats of beef, lamb, and other ruminants, even finding some evidence of a protective effect against heart attacks.

This is good news, and I wish I had heard about it earlier because I love grilled leg of lamb, and especially those brown crispy fatty crusts that are so delicious. I never could resist eating them, despite all warnings about animal fats in general and trans fats in particular. But my health concerns were strong enough to throw away quantities of rendered lamb fat that could have been used in the kitchen. Too bad.

The study about intake of ruminant trans fatty acids and risk of coronary heart disease has been done at the Research Unit for Dietary studies, Institute of Preventive Medicine, Copenhagen University Hospital, Denmark. More than three thousand Danes with healthy hearts have been surveyed and followed up eighteen years, looking at newly developing coronary heart diseases and linking them to dietary habits. In men, no link between heart disease and trans fatties from beef, lamb and other ruminants has been found. In women, those with a high intake of ruminant trans fatties even had a lower risk of heart disease. The study does not go so far to conclude a protective effect for women, but it does not rule it out either.

Complete verdict of not guilty

Ruminant trans fatties are neither reason for heart nor for cancer concerns. The latter is a conclusion of the big food and cancer report, stating that "any effect of trans fatty acids specifically on the risk of any cancer is not known".

Photo credit:

Monday, December 17, 2007

Bone loss surgery

hip bone
Bariatric surgery such as gastric bypass and stomach banding leads not only to weight loss but also to bone loss. This negative side effect is "frequent" according to a review of eleven studies where the effects of weight loss surgery on bone status have been published. The frequency of this unwanted effect contrasts with the high number of stomach surgeries, from twenty up to a hundred, that are needed to prevent one premature death within five years.

When balancing the pros and cons of stomach bypass or banding, all possible complications have to be considered. Unfortunately, only little is known about bone loss. Those patients undergoing gastric banding fare a bit better than those with a Roux-en-Y bypass when it comes to bones. The bone loss is beginning early after surgery, long before a weight loss has occurred. Therefore, it has nothing to do with a weaker weight impact on the bones.

The mechanism is not yet well understood. What can be measured are certain substances in the blood that are known to remove mass from the bones on the one hand and to add new mass to the bones on the other hand. After weight loss surgery, the bone-removing substances prevail. It seems that most is known about the short-term effect of weight-loss surgery on bones. It would be very desirable to learn more about the long-term effects.

Photo credit:

Saturday, December 15, 2007

Dreaming and feeling as a child

Religion is a result of human evolution, and the fact that it has survived the age of enlightenment and scientific reasoning tells us that powerful selection pressures must be at work. I want to find out more, thinking aloud while blogging, and I invite you to follow me. In a previous post I have dealt with the evolution of quackery, and I have come across the idea that quackery and religion share these common traits:

  1. not evidence-based,
  2. relying on "key experiences" rather than statistics and science,
  3. gurus and followers,
  4. becoming more attractive in difficult conditions,
  5. immunity of adherers to scientific reasoning.
By the way, religion is a subject in a number of medical publications, for instance dealing with the question of coping and palliative medicine, therefore it also must be a topic of Med Journal Watch.

The raw material of evolution

Evolution always needs raw material and a status quo from where it can start. For instance, the wings of birds did not evolve out of nothing. They have developed from the forward limbs of quadrupeds. In the case of religion, the raw material has to be found in the brain (religion is a mode of thinking and reasoning) and in the social behaviour (religion is a matter of relationship).

One very impressive mechanism in the brain is dreaming. According to a plausible hypothesis, its function is the transfer of content from short-term to long-term memory. Some phases of this process take place in a semi-conscious state where we have the impression of living in a strange second world or second live. Adults, and children even more, are able to recall what they have experienced in their dreams. Thus, the existence of a “second reality" is a direct and very emotional experience of all human beings. This may be the raw material of all attempts to understand the hidden aspects of our world.

The religions of this world are very different but they share one aspect: A child-like relationship of the adepts or believers towards the deity that is seen as sort of a super-parent. In the beginning of mankind, the powers of nature such as the sun, thunder, storms, rain, the soil, important plants or animals have been worshipped as deities. Later, concepts derived from the family have been developed, "great mother" (magna mater) and "great father in heaven". When we look at all the different rituals in human religions, we always see behaviours of obedience, of submission, of punishment, of forgiving, just as it happens in everyday life between children and parents. Parents are mighty and have the power (at least they are supposed to), and children are dependent and cannot survive without the parents. This is pretty much the same situation as human beings in front of the mighty powers of nature.

The selection process

It is not very surprising that humans try to apply strategies that have been successful in similar situations. For instance, offering a present to appease an angry parent or why not an angry deity in a life-threatening thunderstorm? Religions would not have evolved without a powerful selection pressure fed by situations where humans feel "out of control" and exposed to mighty powers. But here things become complicated. I have to organize my ideas concerning this issue before it is time for a follow-up. Stay tuned.

Photo credit:

Friday, December 14, 2007

Toddlers' fears may begin in the womb

boy crying
Some infants are more fearful than others, and ten percent of these differences are explained by maternal stress, according to a study at two hospitals in London. Prenatal stress of more than a hundred mothers has been assessed, and the cognitive development and the fearfulness of the children has been measured between fourteen and nineteen months of age.

It has been calculated that prenatal stress accounts for 17 percent of the differences in cognitive development and for 10 percent of the differences in fearfulness.

The benefit of a stable relationship

A stable relationship between mother and father, yet before birth, is important for the mental development and well-being of the child. No less than 75 percent of prenatal stress is caused by emotional strain in the partnership, according to the London study.

The mechanisms by which prenatal stress affects the intelligence and the courage of a child are not yet known. What can be said is only that there are two different mechanisms at work and that both of these are not linked. That is, prenatal stress will affect the cognitive development in some infants and fearfulness in others. Which point of weakness will be affected is most likely to be programmed in the genes.

Photo credit:

Thursday, December 13, 2007

Cancer patients less shy, more panicked

Elderly persons after a cancer diagnosis are less likely to be shy in face to face situations but more likely to panic in crowds or open places, compared to healthy persons. This is the surprising result of a study on cancer and mental disorders in Canada.

More than thirty thousand persons of all ages have been assessed. Major depression, not very surprising, has been associated with cancer in all ages between fifteen and over seventy-five. The same holds true for panic attacks.

But in those older than fifty-five, interestingly, the odds of social phobia (shyness) are by a factor of four lower than in healthy persons. In contrast, the odds of agoraphobia (fear of crowds and open places) are by a factor of six higher than in healthy persons.

Minimize danger and maximize help

Elderly cancer patients are facing a shortening life span which inevitably will change their attitude towards life. The remaining life span may be valued as more precious than before. Therefore, it makes sense to avoid situations that are potentially dangerous. On the other hand, the positive side of social relationships, such as help and support, gain value whereas the fear of getting embarrassed becomes less important.

Photo credit:

Wednesday, December 12, 2007

U. S. Trends: Health up, smoking down

Health United States 2007
The good health news, just released by the United States Department of Health and Human Services, contrasts in a very positive way with the fear-raising in most media. I do not share the old saying in journalism, bad news is good news. My fellow blogger against adverse health worries, Sandy Szwarc, gives a quite detailed overview of the report.

When reading mainstream news, we all may come to the false assumption that the whole world is full of risk factors and that we get sicker all the time. But, thanks to the new health report, we know that this is just not true. Period.

I have looked at a number of graphs in the report, many health graphs with an upward trend. The most important downward trend I have come across is smoking. There is a steep decline in most age groups with just one intermediate but not persistent peak in adolescents. I think that the decline in smoking plus a better protection against secondhand smoke is the most important factor leading to a life expectancy that never before has been as high as today.

Tuesday, December 11, 2007

Love is in the genes when it comes to style

Whether we tend to romantic passion or rather to obsessive love mania can partly be seen in certain variants of genes, shaping the substances that make our brains work. Is this the beginning of a new era, ending with "show me your gene card" at the first date?

It is definitely too early for such a prognosis. But for someone asking this question in a distant future, odds would be high that he or she has certain types of the serotonin transporter gene, according to a study on genes and human love styles.

More than a hundred and eighty women and a hundred and sixty men have been studied by researchers of the University of Pavia, Italy. On the one hand, their genes shaping the receptors and transporters of the neurotransmitters dopamine and serotonin have been analyzed. On the other hand, they have passed a psychological test with 24 items, designed to assess love attitudes. Linking both tests revealed very interesting results.

Those men and women with certain types of the serotonin transporter gene are most likely to develop the "Mania" love style characterized by possessive traits and a obsessive attachment with feelings of dependence and low self-esteem. Those with certain types of the dopamine receptor gene are most likely to live the "Eros" style of love with strong romantic feelings based on the physical attraction to the partner. Of course, these distinctions are neither absolute nor exclusive, but they are statistically significant.

So, is love just a matter of genes and body chemistry? Not quite. Four out of six love styles have not (yet) been linked to genes:

  1. "Ludus", love or rather sex as a matter of play or adventure such as in "Dangerous Liaisons".
  2. "Storge", love growing out of friendship such as in "When Harry Met Sally".
  3. "Pragma", love based on calculation rather than emotion.
  4. "Agape", love as a matter of altruism and generosity.


Dopamine plays many important roles in the brain, including cognition, motor activity, motivation and reward, providing feelings of pleasure. The "Eros" love style is linked to the TaqI A variant of the Dopamine D2 receptor gene.
Serotonin plays important roles in the regulation of anger, aggression, body temperature, mood, sleep, vomiting, sexuality, and appetite, providing feelings of activity and in extreme forms, mania or being "high". Low levels of serotonin are linked to depression. The "Mania" love style is linked to the polymorphisms C516T and 5HT2A of the serotonin transporter gene.

Photo credit:

Monday, December 10, 2007

Smart rats and the evolution of quackery

We skeptics have a hard life facing a woo prone majority around us, but the evolution of one of the most successful animals on this planet may tell us why. And knowing why, hopefully, will help us to do a better job.

Evolution of quackery has been the subject of some skeptic posts recently, beginning with Martin's selective pressure towards a null effect, and I have tried to use the model of the random reward Skinner box to explain how methods without any measurable effect can evolve, survive and gain market success.

Both explanations are not yet good enough in letting us understand why quackery is flourishing. Orac, over at Respectful Insolence, points out that applying a homeopathic remedy is not a random setting such as a Skinner box, and he misses the concept of "regression to the mean" or the regressive fallacy. I must admit that I missed to mention this concept, although I had it in mind somewhere. Skeptic's Dictionary:

"The regressive fallacy is the failure to take into account natural and inevitable fluctuations of things when ascribing causes to them. Things like stock market prices, golf scores, and chronic back pain inevitably fluctuate. Periods of low prices, low scores, and little or no pain are eventually followed by periods of higher prices, scores, pain, etc. To ignore these natural fluctuations and tendencies leads to self-deception regarding their causes and to post hoc reasoning."
It is a very strong concept, and I suspect that a very powerful selective pressure must have been working to make it evolve.

Poison-smart rats

So let's step away from pigeons and Skinner boxes and look at another of Skinner's lab animals, but this time in their natural environment. Rats share three traits with us humans: They are smart, they have conquered nearly all regions of this planet, and they are omnivores. The problem with eating a wide variety of food is the danger of getting poisoned by toxic fruits, seeds, roots or, after the evolution of Homo sapiens, rat poison.

The reason why rats have survived even the poisons specially designed to kill them is a smart food behaviour. Whenever they encounter a new food for the first time, they try a very small amount. If they feel well after some hours, they return and try a bit more. If they feel worse, they avoid this food forever. Therefore, smart poisons have been designed against rats, poisons without a short-term adverse effect to circumvent the smart food behaviour of the rats.

A powerful selective pressure

The only reason I have used the rat example is for showing how important a smart behaviour is. Evolution has put an enormous selective pressure on linking behaviour to well-being. Only organisms who are fit in linking causes to effects have survived. Our life is full of examples. Oops, fire is hot. The child never will touch it again. These sorts of things.

When it comes to homeopathy, snake oil or any other quackery, the same mechanism is at work, and it works well. We feel worse. We apply the remedy. We feel better. Now, with our built-in cause to effect linking mechanism, it is very hard not to assume that we feel better because of the remedy.

The illusion of mastery and woo pragmatism

Using snake oil and feeling better is much more rewarding than doing nothing and feeling better. This may be the main reason why snake oil, homeopathy and other quackeries are so successful - not in real effect but on the market. Everybody likes to be in control of things. If we could ask the pigeon in the Skinner box, maybe it would tell us that it is happy to have everything under control.

Knowing this mechanism, does this help us in debating against woo? Not quite, I am afraid. Our problem is that we come along with science and logic, and they counter it with pragmatism. And if a pragmatism is working well in everyday life, there is nothing against it. Every smart trainer knows that you never change a winning team. He will listen carefully to any scientist and logician suggesting a better solution. He even may agree to the reasoning. But then he will just say hey, we have won our last game with this team, and I am not so stupid to change it.

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Friday, December 7, 2007

Twenty stomach surgeries may save one life at best

stomach surgery
But in smaller clinics without star surgeons, it may take up to a hundred gastric bands to prevent one death of an obese patient in five years. These are the very mixed results of three recent studies on the long-term effect of bariatric surgery.

First, let's take a comparing look at everyday routine cases like a sore appendix where surgery is necessary to prevent a risk of death within a few days. No question, appendix surgery is simple and immediately life-saving.

Gastric banding, on the other hand, is complicated, and the question if it is life-saving must remain open, without clear-cut answers. Too much depends on the details. Three studies have been published recently, telling us that bariatric surgery (gastric banding) may reduce the relative risk of death in the following five years by 64 percent in Italy, 72 percent in Australia or even 89 percent in Canada, compared to obese patients without surgery.

Translating relative risks to real figures

The 89 percent lower risk reported in the Canadian study sounds impressive. But what does it mean? In a group of 1035 surgical patients, seven (0.68 %) have died, and in a larger group of 5746 patients without surgery, three hundred fifty-four (6.17 %) have died. Without surgery, 64 of the 1035 patients may have died within five years. That is, for every life saved, 18 surgeries have been performed, about twenty given the statistical uncertainty.

Applying the same calculation, the numbers of surgeries needed for saving one life are about 58 in Italy and about 96 in Australia.

Much depends on the surgeon

It is interesting to see how the best performance in Canada has been reached. All 1035 surgeries have been done at one high volume clinic at McGill University Health Centre in Montreal, Canada. One single star surgeon performed 49 percent of all cases, another 48 percent have been performed by three other surgeons, and the tiny rest by another three surgeons.

Now let's have a look at Germany where no world's best teams are available. In a low-volume clinic at W├╝rzburg, only eighty-five obese patients within six years have received a gastric band. The study reports only 37 percent success compared to 63 percent failures where either the bands had to be removed or the weight loss goal has not been reached. Long-term mortality has not been assessed in this study, but looking at Australia or Italy, one may guess that much more than a hundred gastric bands may be required to save one life in Germany. With a life-saving success of less than one percent, we get close to the world-wide mortality rate of 0.25 percent after bariatric surgery.

Is it the weight loss, anyway?

Looking again at the best possible conditions in Canada, we see that a stomach band may lead to weight loss and may reduce mortality. But weight loss, a clearly visible sign of long-term success, is not the most likely cause of better health but rather a visible sign of it, too.

Many of the very obese patients are diabetics, and after bariatric surgery, diabetes improves within weeks, long before any weight loss can be seen. Thus, a very strong positive effect of gastric banding is independent of weight loss. A number of favourable changes in hormones and metabolism are caused by the banded stomach. These changes influence the risk of, for instance, a heart attack on the one hand and lead to a reduction of body fat on the other hand. In other words, reduced risk as well as reduced body fat may both be caused by gastric banding.

Conclusions: If not done in a high-volume clinic by top surgeons, gastric banding may have a poor success. Weight loss is a visible long-term outcome of successful gastric banding (bariatric surgery), but immediate and ongoing changes in metabolism are the most likely causes if health improves after surgery.

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Thursday, December 6, 2007

Most problems with first sex very early or very late

teen love
When it comes to the first sex, waiting can avoid many problems but waiting too long may also cause problems. This is the conclusion of a study about the long-term health consequences of the timing of sexual debut. More than eight thousand adults have been surveyed in 1996.

The problem with sex at age fourteen is associated with risky sex, sex with more partners, sex under influence of alcohol or drugs, and with arousal and orgasm problems.

But the opposite, waiting until marriage, is not the best solution. While first sex after age twenty-two is linked to safer sex, it is not linked to better sex: The late starters have the same functional problems with arousal and orgasm as the early starters. The most satisfying sex life has been linked to a first sex between age seventeen and twenty-one.

The timing of first sex is important for sex but not for love and for the stability of the current partnership: These are not associated with early or late initiation.

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Wednesday, December 5, 2007

Newspeak and doublethink of Big Tobacco

PM screenshot
A big tobacco company is hiding an unpleasant strategy behind pleasant sounding words, just as described by George Orwell. In his novel "Nineteen Eighty-Four", Orwell has invented "newspeak" that allows to make lies sounding like truth, and “doublethink" for dealing with two opposite realities at the same time, hiding that there is any contradiction.

The newspeak of Philip Morris, as can be seen on its website, are statements such as "smoking is dangerous and addictive" and that "secondhand smoke from cigarettes causes disease, including lung cancer and heart disease, in non-smoking adults, as well as causes conditions in children such as asthma, respiratory infections, cough, wheeze, otitis media (middle ear infection) and Sudden Infant Death Syndrome."

For decades, the company had denied that smoking causes disease and is addictive. The new language on its website seems to show that the company has changed its opinion. But this is not true. Lissy C. Friedman has found out that Philip Morris mislead the public into believing that it has changed its stance on smoking and disease. After having studied internal documents and various draft and final versions of the new public statements as well as statements made in tobacco trials, she concludes:

"Philip Morris created and disseminated its website’s message that it agreed that smoking causes disease and is addictive in an effort to sway public opinion, while maintaining in a litigation setting its former position that it cannot be proved that smoking causes disease or is addictive."
This newspeak, obviously, is based upon doublethink - on the one hand telling the public that smoking is dangerous and addictive and on the other hand stating in the courtroom that it is neither dangerous nor addictive.

Tuesday, December 4, 2007

Pap smear may not only detect but also protect

pap smear
The Papanicolaou test has been designed for early detection of a virus-caused cancer, but it also improves the protection against this cancer and against other diseases caused by sexually transmitted viruses.

This unexpected protective effect of the Pap smear has been found in South Africa where hormonal contraceptives and cervical cancers have been studied in more than fifteen hundred women. Besides pap smears for detection of the cancers and the human papilloma virus (HPV) that causes them, the blood of the women has also been studied in order to detect other sexually transmitted viruses. It came out that not only HPV but also Herpes and HI viruses have been reduced in women who have received the most Pap smears.

It seems to be a clear relation of cause and effect: The more Pap smears, the less viruses, and the more recent Pap smears, the better the protection. For instance, a Pap smear in the previous year reduces the odds ratio of being infected by Herpes simplex virus versus being not infected by 60 percent; this reduction is only 20 percent if the last Pap smear is ten or more years back.

Even for HIV, a protection has been observed but, of course, relying on Pap smears and not using condoms would be a very, very bad idea.

Being cautious also reduces the risk

A pap smear seems to protect against sexually transmitted viruses, but how? The study cannot answer this question. Indirect actions cannot be ruled out. For instance, a "cautious" or "careful" lifestyle may be linked to more Pap smears on the one hand and to less sexual partners on the other hand, and the number of sexual partners is one of the major risk factors for sexually transmitted diseases. Thus, more studies are required to find out if the protection is really due to the Pap smear.

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Monday, December 3, 2007

Fitness, in spite of fatness, helps the heart

By exercise, diabetics can reduce inflammation and other risk factors for heart attack, even without weight loss. This has been shown in a Greek trial with sixty diabetics. Half of them, randomly assigned, exercised aerobics four times a week, approximately one hour, for half a year. The other half did not exercise and served as control. Fitness, body weight and a number of lab values have been assessed at the start and at the end of the trial.

It came out that those who exercised did not lose weight but improved in fitness, blood sugar control, blood fat profile, and the markers of inflammation decreased markedly. In other words, the whole metabolism improved and shifted towards a better health for the heart and a decreased risk for heart attack.

Admittedly, this study has tested only a small number of persons. Admittedly, only indirect lab values (and not heart attacks) have been evaluated. All the same, this study gives useful insight into some causal mechanisms of metabolism and body weight. Obviously, a bad metabolism goes together with increased body fat in diabetics. But the intervention shows that body fat seems not to be the cause of this bad metabolism because metabolism may improve well without any change in weight.

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Saturday, December 1, 2007

Random reward may explain why homeopathy still exists

When millions of patients all over the world are using remedies without any molecule of active substance, there must be at least one natural mechanism that rewards nonsense. And such a mechanism exists, as B. F. Skinner has shown in an experiment with pigeons, many years ago. I suggest that this very mechanism, random reward, may explain the evolution of homeopathy.

Martin Rundkvist, at Aardvarchaeology, has developed a nice theory which explains some aspect of this evolution. In brief: There is a selective pressure on altie medicine towards a null effect (1) because if it turned out to be effective, it would be classed as evidence-based, no longer as altie, and (2) because if it turned out to be harmful, it would be classed as dangerous and would be forbidden or abandoned. While this theory does a good job in explaining how an already existing altie method is being classified as altie, it falls short in explaining how it did evolve, how it survives extinction by lack of demand and by unwillingness of users to pay good money for nonsense, and how it even managed to invade the realm of university medicine.

B. F. Skinner's random reward experiment

As a student of biology (university diploma in animal behaviour) I have been very fascinated when I've learnt of this experiment. Briefly, a Skinner box is a cage where animals such as rats and pigeons can be trained on the task of pressing a button or key which is rewarded with food when done properly. One day, Skinner had the idea of giving a pigeon food pellets on a random basis, typically about four times a minute. There was no task. Some days later, the pigeons used to behave in a very strange way: One has been turning left all the time, another one turning right, another one was scratching the floor all over again, yet another one shaking plumage. Any behaviour that a pigeon can show, just by random, has been enforced in a crazy way. This has been observed not only in pigeons used to the Skinner box but also in naive pigeons.

A simple mechanism: reinforcement

The natural foraging behaviour of pigeons is the search of small food units in a complex environment. Whenever they find a grain, they will repeat the specific behaviour unit that led to the food. That is, a pigeon has some built-in concept of cause and effect. In the Skinner box, when the pigeon gets its random food pellet, the random behaviour of the pigeon will be enforced in a way that the pigeon shows it more often, increasing the odds of being awarded again, which enforces even more, and so on until we see that crazy behaviour.

I think that this random reward model may also explain altie medicine, for instance homeopathy. The pigeon is a model of the user. The random pellet is a model of the ups and downs in wellbeing and medical symptoms of the user. And, last but not least, the nonsensical behaviour of the pigeon is a model of the user taking nonsensical remedies.

Similia principle as a first random pellet

Just like pigeons, humans are programmed in detecting patterns in a complex world. Such a pattern has been detected by Samuel Hahnemann who, using china-bark (a herbal remedy against malaria) as a healthy person, later has been suffering from symptoms similar to malaria. Based on this "similia principle", he invented a totally different kind of medicine, homeopathy. His fever - the random pellet (a bad one of course). Taking china bark in self-experiment - the random behaviour.

A modern scientist would have repeated the trial with different persons under different conditions. Hahnemann, convinced of having detected a fundamental principle, looked for more similia cases and of course found them which reinforced his theory.

The modern user of homeopathy

Time has gone by. Today, millions of users are taking plain solvent, sold as homeopathic remedies. Again, we may use the Skinner box as a model to explain their behaviour. The worsening of symptoms is analogue to the condition without food pellet. The betterment is analogue to the pellet. And we all know that the whole life is based on rhythms - by the way a fundament of many woo theories (their arguments can be turned against them). That is, on a more or less random basis, symptoms come and go, wellbeing waxes and wanes. The best example is malaria, Hahnemann's first similia paradigm, causing periodic fever attacks.

Now, feeling worse, our user will take some drops of solvent or globules of sugar containing no effective substance - the analogue of the nonsensical behaviour of the pigeon. He will continue to do so until he feels better, which is the analogue of the random pellet that inevitably will be given. Next time when feeling worse, he will not just take the remedy but he will take it "because it had helped me before" - and here we have the analogue of Skinner's reinforcement of a behaviour element.

Resistance against logic reasoning

Needless to say that you can't tell the pigeon that it will get the pellet anyway and that it should stop behaving crazily. This is beyond its perception of the world. But it is really intriguing that the same holds true for humans. Tell them that nothing is in the remedy, and that the whole theory of action is absurd, and that science has refuted it, and they will tell you: But I have taken it yesterday, and now I feel better, and don't tell me it's just placebo because I gave it to my halting horse and now I can go out for a ride.

Orac and others have commented on this post here, and here is my own follow-up.

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