Category: ignorance

Brainwashing in High Places: Genes and Disease

Seth Roberts4 Comments

From an article by Nicholas Wade in the NY Times:

Since the human genome was decoded in 2003, researchers have been developing a powerful method for comparing the genomes of patients and healthy people, with the hope of pinpointing the DNA changes responsible for common diseases.

This method, called a genomewide association study, . . . has been disappointing in that the kind of genetic variation it detects has turned out to explain surprisingly little of the genetic links to most diseases.

Wade means the genetic variation is surprisingly poor at distinguishing healthy people and sick people. That is the empirical result.

Unlike the rare diseases caused by a change affecting only one gene, common diseases like cancer and diabetes are caused by a set of several genetic variations in each person.

This is the faith-based statement. Wade knows this how? What about the possibility that cancer and diabetes are caused by environmental differences? That there are consistent environmental differences (e.g., dietary differences) between those who get cancer and those who don’t?

I know of no evidence that common diseases like cancer and diabetes are caused by several genetic variations in each person. I know of a lot of evidence that they are caused by the wrong environment — lung cancer caused by smoking, for example.

Preachers say: If you do X, you will go to heaven. In other words, do something that helps me (the preacher) now and you will benefit later. It has been an effective argument. This is what the geneticists have been doing. They say to granting agencies — who believe what they read in the NY Times — if you give us money now we will find the genetic basis of Disease X. Just as there was no clear reason to believe the preachers’ claims, there was no clear reason to believe the geneticists’ predictions. Which unfortunately for them can be shown to be wrong.

The success of my self-experimentation at solving common problems led me to think the environment is more powerful than NY Times readers, or at least NY Times reporters, had been led to believe. Good news for people with problems but bad news for scientists who want large grants. My research was essentially free.

History Repeating Itself: Fear of Bacteria

Seth Roberts2 Comments

In the late 1800s in the United States, babies started developing scurvy; there was a veritable plague. It turned out that the vast majority of victims were being fed milk that had been heat treated (as suggested by Pasteur) to control bacterial disease. Pasteurization was effective against bacteria, but it destroyed the Vitamin C.

From a history of nutrition. Now children are probably getting all sorts of immune disorders, such as hay fever, for the same core reason: fear of bacteria.

Nobel-Prize Cluelessness (stomach ulcers)

Seth Roberts14 Comments

Wherein the Nobel Prize is given for discoveries that are misleading. From a New Scientist article about medical self-experimentation:

Junior doctor Barry Marshall was sure the medical establishment was wrong about the cause of stomach ulcers. The received wisdom was that they were caused primarily by lifestyle factors, but Marshall and pathologist Robin Warren were sure that the bacterium Helicobacter pylori was to blame.

It turned out that Helicobacter pylori was present in half the stomachs in the world — only a tiny fraction of which developed ulcers. So much for causation. Marshall and Warren did not consider that lifestyle factors might cause immune efficiency to go down, leading to increased growth of the bacterium. In a famous example of self-experimentation, Marshall ingested a giant amount of the supposedly dangerous bacterium — but, uh-oh, didn’t get an ulcer.

Thanks to JR Minkel.

Will Like vs. Might Love vs. Might Hate

Seth Roberts2 Comments

What to watch? Entertainment Weekly has a feature called Critical Mass: Ratings of 7 critics are averaged. Those averages are the critical response that most interests me. Rotten Tomatoes also computes averages over critics. It uses a 0-100 scale. In recent months, my favorite movie was Gran Torino, which rated 80 at Rotten Tomatoes (quite good). Slumdog Millionaire, which I also liked, got a 94 (very high).

Is an average the best way to summarize several reviews? People vary a lot in their likes and dislikes — what if I’m looking for a movie I might like a lot? Then the maximum (best) review might be a better summary measure; if the maximum is high, it means that someone liked the movie a lot. A score of 94 means that almost every critic liked Slumdog Millionaire, but the more common score of 80 is ambiguous: Were most critics a bit lukewarm or was wild enthusiasm mixed with dislike? Given that we have an enormous choice of movies — especially on Rotten Tomatoes – I might want to find five movies that someone was wildly enthusiastic about and read their reviews. Movies that everyone likes (e.g., 94 rating) are rare.

Another possibility is that I’m going to the movies with several friends and I just want to make sure no one is going to hate the chosen movie. Then I’d probably want to see the minimum ratings, not the average ratings.

So: different questions, wildly different “averages”. I have never heard a statistician or textbook make this point except trivially (if you want the “middle” number choose the median, a textbook might say). The possibility of “averages” wildly different from the mean or median is important because averaging is at the heart of how medical and other health treatments are evaluated. The standard evaluation method in this domain is to compare the mean of two groups — one treated, one untreated (or perhaps the two groups get two different treatments).

If there is time to administer only one treatment, then we probably do want the treatment most likely to help. But if there are many treatments available and there is time to administer more than one treatment — if the first one fails, try another, and so on — then it is not nearly so obvious that we want the treatment with the best mean score. Given big differences from person to person, we might want to know what treatments worked really well with someone. Conversely, if we are studying side effects, we might want to know which of two treatments was more likely to have extremely bad outcomes. We would certainly prefer a summary like the minimum (worst) to a summary like the median or mean.

Outside of emergency rooms, there is usually both a wide range of treatment choice and plenty of time to try more than one. For example, you want to lower your blood pressure. This is why medical experts who deride “anecdotal evidence” are like people trying to speak a language they don’t know — and don’t realize they don’t know. (Their cluelessness is enshrined in a saying: the plural of anecdote is not data.) In such situations, extreme outcomes, even if rare, become far more important than averages. You want to avoid the extremely bad (even if rare) outcomes, such as antidepressants that cause suicide. And if a small fraction of people respond extremely well to a treatment that leaves most people unchanged, you want to know that, too. Non-experts grasp this, I think. This is why they are legitimately interested in anecdotal evidence, which does a better job than means or medians of highlighting extremes. It is the medical experts, who have read the textbooks but fail to understand their limitations, whose understanding has considerable room for improvement.

What One Economist Has Learned From the Financial Crisis

Seth Roberts3 Comments

Three things, he said:

  1. Finance professors have all been working for hedge funds. Their research has been about how to price derivatives and options. In other areas of economics, the research topics are much broader and include policy questions.
  2. Macroeconomics hasn’t made progress since the 1930s.
  3. Recommendations what to do about the crisis, even from economics professors, are based on very little they learned in graduate school. They hardly differ from opinions. Listening to his colleagues’ recommendations, he thought they would be backed up by something solid. They weren’t.

Standing, Sleep, and Stereotype Threat

Seth Roberts6 Comments

Part of my long self-experimentation paper was about a connection between standing and sleep. If I stood a lot (more than 8 hours), I slept better.

Why might this be? I argued that if you use sleep to maintain muscles, you will begin to need sleep to maintain muscles. (And the more you use a muscle, the more maintenance it needs. Thus the stand/sleep connection.) Catherine Johnson describes here a parallel process: Because men opened doors for her (in college), she began to need them to open doors for her. In situations where she was stereotypically expected to be weak, she actually became weaker (mentally).

However much sense this makes it is not part of conventional thinking. Should we fight against germs by killing them? Of course, says the conventional problem solver. The notion that germs might keep us strong isn’t part of the discussion. Let me be more explicit: If you make everything clean you may begin to need everything clean. The overwhelming evidence for the hygiene hypothesis shows that this line of thinking is reasonable.

So that’s three examples of a general principle, an advanced version of “use it or lose it”.

If you think this is somehow obvious, let me ask: What about terrorism? Should we simply try to eliminate it? Or is the question of how to respond more complex?

The Twilight of Expertise (medical doctors)

Seth Roberts10 Comments

Long ago the RAND Corporation ran an experiment that found that additional medical spending provided no additional health benefit (except in a few cases). People who didn’t like the implication that ordinary medical care was at least partly worthless could say that it was only at the margin that the benefits stopped. This was unlikely but possible. Now a non-experimental study has found essentially the same thing:

To that end, Orszag has become intrigued by the work of Mitchell Seltzer, a hospital consultant in central New Jersey. Seltzer has collected large amounts of data from his clients on how various doctors treat patients, and his numbers present a very similar picture to the regional data. Seltzer told me that big-spending doctors typically explain their treatment by insisting they have sicker patients than their colleagues. In response he has made charts breaking down the costs of care into thin diagnostic categories, like “respiratory-system diagnosis with ventilator support, severity: 4,” in order to compare doctors who were treating the same ailment. The charts make the point clearly. Doctors who spent more — on extra tests or high-tech treatments, for instance — didn’t get better results than their more conservative colleagues. In many cases, patients of the aggressive doctors stay sicker longer and die sooner because of the risks that come with invasive care.

Perhaps the doctors who ordered the high-tech treatments, when questioned about their efficacy, would have responded as my surgeon did to a similar question about the surgery she recommended (and would make thousands of dollars from): The studies are easy to find, just use Google. (There were no studies.)

It’s like the RAND study: Defenders of doctors will say that some of them didn’t know what they were doing but the rest did. But that’s the most doctor-friendly interpretation. A more realistic interpretation is that a large fraction of the profession doesn’t care much about evidence. In everyday life, evidence is called feedback. If you are driving and you don’t pay attention to and fix small deviations from the middle of the road, eventually you crash. You don’t need a double-blind clinical trial not to crash your car — a lesson the average doctor, the average medical school professor, and the average Evidence-Based-Medicine advocate haven’t learned.

How Bad is LDL Cholesterol? (continued)

Seth Roberts1 Comment

If LDL cholesterol level predicts heart disease then persons with low LDL should be better off than persons with high LDL. Here is what some Norwegian doctors did:

They simply selected sequential patients with LDL cholesterol scores below 2.7mmol/l. . . . They ignored all people with LDL concentrations from 2.7 to 4.5mmol/l but did enroll all people with an LDL >4.5mmol . . . So they then had two groups of people, those at catastrophic risk of LDL-blocked-arteries and those with [very] little LDL . . . They did the scheduled angiography and checked how many patients had >70% blockage of at least two coronary arteries in each group.

Guess what: LDL cholesterol doesn’t matter. They recruited 47 patients with low LDL-C, of whom 21 had significant CAD. They got 46 high LDL-C patients, of whom 24 turned out to have CAD.

Thanks to Dave Lull.

How bad is LDL cholesterol?

How Bad is LDL Cholesterol?

Seth Roberts17 Comments

We all know the term bogeyman — a fictional monster that empowers its inventor. According to Wikipedia, “parents often say that if their child is naughty, the bogeyman will get them, in an effort to make them behave.” I always think of the Falkland Islands. In 1982, by acting as if the Argentine invasion actually mattered, Margaret Thatcher got herself a big boost in popularity. In the 1960s, by acting as if Berkeley student protests were dangerous, Reagan got elected president. The day after 9/11, I said my big fear was overreaction. I doubt the persons behind the bombing understood how useful they were to those in power. Bush got a boost in popularity that lasted years.

When it comes to health, cholesterol is one of the biggest bogeymen. Hyperlipid begins a post about LDL cholesterol like this:

You would be forgiven for thinking that the apoB100 protein (which defines the LDL or VLDL particle) has been evolved over the past 4.5 billion years to cause cardiovascular disease and the less of it you have the longer you will live. Listening to a cardiologist that is (or a BBC reporter on the Today Program grovelling before a cardiologist). The lower the better. It’s impossible to have too low an LDL concentration. Statins in the drinking water. You know the patter.

The scientific paper on which his post is based concludes:

Apolipoprotein B at homeostatic levels in blood is an essential innate defense effector against invasive S. aureus infection.

Thanks to Dave Lull.