No, in fact I am suggesting that H. Pylori is the cause of all peptic ulcers.
~ Barry Marshall 1983 just before an entire auditorium walked out on his presentation on the causes of peptic ulcers, previously believed to be the manifestation of a large number of distinct underlying conditions.
From Wikipedia 2012
A peptic ulcer, also known as PUD or peptic ulcer disease,[1] is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm. As many as 70–90% of such ulcers are associated with Helicobacter pylori
Kevin Drum writes
Don’t forget lead! Lead lead lead lead. When is the connection between reduced lead levels and reduced crime levels finally going to penetrate the minds of American journalists? I know it’s not sexy and I know everyone wants to ignore it because you can’t tell heroic stories about lead, but it’s almost certainly the single biggest contributor to crime reductions nationwide.
I don’t know the research behind lead and crime. However, overwhelmingly the presumption should be that epidemics have a single precipitating factor.
People are sometimes confused by the fact that complex conditions have a long list of necessary factors. However, the odds against more than one necessary factor pushing the phenomenon across the line into epidemic at the exact same time are astronomical.
Not to go to far astray but this is why recessions likely have a single precipitating factor. They spread too fast and burn out too quickly to be multi-casual. A fifty year period of off and on stagnation, that might be multi-causal. An 18% collapse in industrial production over 18 months? That has a vector.
A good rule of thumb – I believe – for epidemics economic, biological or social is this: If it spreads along lines of communication its entropic information. If it travels along major transportation routes its microbial. If it spreads out like a fan, its an arthropod. If its everywhere, all at once, its a molecule.

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Sunday ~ January 8th, 2012 at 11:14 am
Sanjay
Maybe a bad example. THe microbiology literature went from saying, nope, _pylori_ doesn’t cause ulcer, to yep, _pylori_ is the cause of peptic ulcer, and recently the pendulum is swinging back (and actually personally I think the “nopes” have it — _pylori_ looks like something really important that you _want_ to have — all mammal species have _pylori_ and in fact each mammal has its own distinctive serotype; the mainstream thinking now I think, is that it helps regulate stomach pH).
Sunday ~ January 8th, 2012 at 12:28 pm
Karl Smith
Good to know – I use that example every semester so I will want to update
Sunday ~ January 8th, 2012 at 12:24 pm
saiaj
About the whole lead thing. I remember reading a paper a couple years ago that compared the usage of lead paint in public housing and crime rates in a good number of cities in the US and Europe and found a really strong correlation between the amount of public housing with lead paint and the crime rate 20 years later in every city.
I really wish I could find that paper again. It was linked to in some blog, might have been Ezra Klein’s but can’t find it right now.
Sunday ~ January 6th, 2013 at 4:24 pm
Jean-Victor Côté
“MJ: Even today most people think of lead paint when they think of lead poisoning.
HM: In the 1970s, there was an article in the journal Environmental Health Perspectives by Gary Ter Haar that stated basically paint was causing the major pollution of lead in urban soils. When we looked at Baltimore, the pattern we were finding was the opposite of what you would expect. It turns out Gary Ter Haar worked for the Ethyl Corporation [which manufactured the lead additive for gasoline]. There was a huge conflict of interest. The idea of paint being the major contributor of lead to the soil came from people who had a very long vested interest in not letting the cat of the bag.”
Source: http://www.motherjones.com/environment/2012/12/soil-lead-researcher-howard-mielke
Sunday ~ January 8th, 2012 at 12:41 pm
Matt D
Karl, I disagree.
A single causal factor may have been previously present, but constrained or buffered by other factors that have changed. Cancer is an example; it’s an epidemic in a single organism.
Some cancers are associated with multiple genetic defects. You can get cancer with any single defect, but your odds are much greater when you have many in tandem. Sometimes you have a few in the wild type, and then a mutation occurs in a single cell, which then becomes cancerous. There may be a dominant driver, but this can still be called multifactorial, and it doesn’t occur with just cancer.
Sunday ~ January 8th, 2012 at 1:07 pm
Karl Smith
Part of it is a matter of your perspective. Because you are looking from the outside at an accumulation of factors it can make sense to call it multi-causal.
However, if you were inside the body watching one particular epidemic unfold you would say: “It all started with cell X when Y happened”
Also we are dealing with a population of some 10 Trillion cells some of which have a rapid turnover, so the odds of hitting two necessary factors over the entire life time of the organism is fairly high. Though, even still you would probably say it all started with cell X when Y happened.
Sunday ~ January 8th, 2012 at 6:41 pm
Matt D
Karl, I guess it hinges on vocabulary. If you’re considering “precipitating factors”, then almost by definition there can be only one.
But to me that seems people usually care about the causative factors: what happened to cause this thing, so we can prevent it next time? In that case, it’s a mistake to single out one event when there are many equal contributors. Not just in cancer, but in recessions and crime too.
Tuesday ~ January 10th, 2012 at 4:35 pm
jam
Reminds me of Feynman talking about why Aunt Minnie slipped on ice.
Seems to me like a person probably only cares about the deeper causality if they believe that it would be cheaper to fix the problem earlier in the chain, or if they believe there are other related problems that are conditional to the deeper cause…
…and in fact there probably are deeper causes and related problems, but the further away you get from the effect, the harder it is to say whether those deeper causes aren’t also beneficial in other ways that we fail to think of.
If we had the ability to re-design water so that it doesn’t expand when it solidifies, that would save a lot of Aunties from falling. But it’d probably be disastrous for life as we know it. It’s hard to tell apriori.
Usually, the safest and cheapest thing to fix is the single “precipitating factor”.
Wednesday ~ January 11th, 2012 at 8:59 am
Matt D
Jam or Karl,
Forget Aunt Minnie. What was the single factor we should fix next time to avoid a recession occurring for the same reason this one did?
What single factor should have been rectified to avoid World War I? If your answer is “protect Archduke Franz Ferdinand at all costs”, you’re conceding my point.
Sunday ~ January 8th, 2012 at 1:10 pm
david
Where is the quote from? At least part of it is wrong according to Wikipedia; H. Pylori was known as Campylobacter Pylori at least until 1989.
It’s a snappy quote, though.
Sunday ~ January 8th, 2012 at 2:25 pm
John Field
I believe this is wrong, Karl.
Study random matrix theory. The distribution of eigenvalues of a random matrix are distributed in a highly correlated way. Small changes in the matrix elements can cause large shifts in the eigenvalues and thus small events can lead to big effects which can only be understood as the sum of a large number of different forces.
Now, sure it is possible to examine the matrix in a coordinate frame in which the eigenvectors are the forces. Then, it all looks like it is being caused by a single force, but there is nothing – nothing at all – to ensure or even make it likely that the eigenvector is a simple combination of more fundamental driving forces.
Monday ~ January 9th, 2012 at 9:59 am
Mr. Violet (@EuropeanViolet)
“A good rule of thumb – I believe – for epidemics economic, biological or social is this: If it spreads along lines of communication its entropic information. If it travels along major transportation routes its microbial. If it spreads out like a fan, its an arthropod. If its everywhere, all at once, its a molecule.”
Have you applied it to obesity? I know you studied the subject, but I do not know your conclusions about it, maybe they are on the blog already.
Friday ~ January 4th, 2013 at 11:35 am
Paul N
Good Question: Obesity is related to Diabetes Type 2 (I have some personal experience) This disease is related to two factors. (1) The amount of fat along the nerves serving the pancreas. This presents as the insulin resistance but in fact is a Glycogen issue and the nerves are not releasing Glycogen properly due to fat along the nerves (2) Certain dietary factors are stimulating growth of bacteria that are releasing hormones that cause dietary intake to rise and the storage of fat. These have one very clear molecule indicator. It is the GMO (BT) gene. The fat epidemic in the world is precisely matched to the presence of the BT gene in food supplies. The import of BT foods and domestic BT foods has recently (Past 10 years) entered the Philippines and now everyone is getting fat there. This entered the USA about 30 years ago.
I got your molecule for you. Go get it!
Monday ~ January 9th, 2012 at 10:57 am
Barry
Please note that you’re wrong on two of these – I’ve read an account of the spread of a spider in the USA, which was strongly along transportation lines (the spiders nested and laid eggs in vehicles). Molecules are where people initially put them, and then spread by water and air. Acid rain was rather localized in the USA, for obvious reasons. I’d guess that lead concentrations are localized, as well.
Tuesday ~ January 10th, 2012 at 10:22 am
Gene Callahan
Reality is complex and multifaceted. When someone cannot cope with reality, they devise simple-minded formulas like, “overwhelmingly the presumption should be that epidemics have a single precipitating factor.” Such a person has learned to deal with reality as a “model,” rather than as actual, concrete existence.
Wednesday ~ January 11th, 2012 at 3:24 am
Links – January 10, 2012 | zota
[...] Modeled Behavior [...]
Wednesday ~ January 11th, 2012 at 3:03 pm
neil
I liked this post when I first read it, but since then (maybe it’s too late to usefully comment) it’s been eating at me. I think the key was your use of the word ‘precipitating’ that kept me thinking.
It’s undeniably true that when an event has a precipitating cause, it wouldn’t happen in the absence of that cause. But the only thing that makes that precipitating cause more important is that it’s (sometimes) the one we can see most clearly in hindsight. So maybe it’s useful for pundits or economists trying to explain the past, but for people trying to influence the future, it is not useful at all.
Perhaps a simple analogy. Let’s say the pilot light on my furnace blew out, and now my house is full of gas. If the precipitating factor of a lit match is introduced, my house will explode. It would be crazy to say that to save my house, I must focus on protecting it from lit matches. I would do much better to open a window and vent the gas, so that a lit match will cease to be a potential precipitating cause.
A more metaphorical example that comes to mind is that of the little kids playing soccer. They know that the ball is the precipitating cause of a goal, so they all run after the ball in a line. This is highly ineffective in comparison to professional soccer players, who know that they can’t all focus on the precipitating cause; they need a multivariate strategy which involves setting up the secondary conditions that allow the precipitating cause to result in a goal.
Friday ~ August 10th, 2012 at 2:05 pm
causes of bloating after eating a meal
High-quality post. Looking forward to the following one.
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lot of followers in no time.
All the best, and definitely checking for your future posts.
Thursday ~ January 3rd, 2013 at 3:35 pm
America’s Real Criminal Element: Lead by Kevin Drum | Creativeconflictwisdom's Blog
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Thursday ~ January 3rd, 2013 at 6:03 pm
Good summary of solid studies showing the role of environmental lead in criminal violence « Later On
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Thursday ~ January 3rd, 2013 at 7:53 pm
Kelsay
Does the author know the difference between “its” and “it’s”?
Friday ~ January 4th, 2013 at 2:53 am
America’s Real Criminal Element: Lead « Random Ramblings of Rude Reality
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Friday ~ January 4th, 2013 at 4:07 am
LokalFilmer » America’s Real Criminal Element: Lead
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Friday ~ January 4th, 2013 at 1:11 pm
The Starting Line – Qualcomm Under Fire, Al Jazeera’s Growing, and Birthers Run Amok
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Saturday ~ January 5th, 2013 at 5:58 pm
Christopher A. Haase » Blog Archive » America's Real Criminal Element: Lead | Even low levels have a significant effect on I.Q. & Crime
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Sunday ~ January 6th, 2013 at 5:04 am
Rise and Fall of Lead in our Housing and Atmospheres Explain Post WWII Crime Rates Locally and Worldwidey | Eslkevin's Blog
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Sunday ~ January 6th, 2013 at 2:05 pm
America’s Real Criminal Element: Lead | OCG
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Sunday ~ January 6th, 2013 at 3:39 pm
America’s real criminal element: lead — War in Context
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Friday ~ January 11th, 2013 at 5:31 am
Environmental Lead and Crime — A Story of How Science Needs Storytellers « The Scholarly Kitchen
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Sunday ~ January 13th, 2013 at 8:54 am
Get The Lead Out…And Slash Violent Crime Rates « masscommons
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Monday ~ January 21st, 2013 at 9:53 pm
America’s Real Criminal Element: Lead | The Shyne School
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Tuesday ~ January 29th, 2013 at 9:46 am
NexuxIlluminati – America’s Real Criminal Element : Lead – 29 October 2013 | Lucas 2012 Infos
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Wednesday ~ February 13th, 2013 at 2:34 pm
America’s Real Criminal Element: Lead « Read Think Write Teach
[...] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. [...]
Saturday ~ March 30th, 2013 at 4:32 pm
As Philadelphia's Lead Exposure And Poisoning Epidemic Is Controlled, Crime Will Fall - Beasley Firm Injury and Malpractice Lawyers
[...] of an epidemic, researchers often use as a rule of thumb, “If it travels along major transportation routes its microbial. If it spreads out like a fan, [...]
Monday ~ May 13th, 2013 at 12:08 pm
America’s Real Criminal Element: Lead | lisaleaks
[…] of public economics and government at the University of North Carolina-Chapel Hill, has a good rule of thumb for categorizing epidemics: If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. […]