Crohn's Disease and Early Exposure to Domestic Refrigeration

[kiny]

Full: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004288

Crohn's Disease and Early Exposure to Domestic Refrigeration

Fatemeh Malekzadeh,1 Corinne Alberti,2,3 Mehdi Nouraei,1 Homayoon Vahedi,1 Isabelle Zaccaria,2,3 Ulrich Meinzer,4,5,6 Siavosh Nasseri-Moghaddam,1 Rasoul Sotoudehmanesh,1 Sara Momenzadeh,1 Reza Khaleghnejad,1 Shahrooz Rashtak,1 Golrokh Olfati,1 Reza Malekzadeh,1 and Jean-Pierre Hugot

Unité d'épidémiologie clinique, Paris, France

University of Tehran, Iran

2009 January 29

Background

Environmental risk factors playing a causative role in Crohn's Disease (CD) remain largely unknown. Recently, it has been suggested that refrigerated food could be involved in disease development. We thus conducted a pilot case control study to explore the association of CD with the exposure to domestic refrigeration in childhood.

Methodology/Principal Findings

Using a standard questionnaire we interviewed 199 CD cases and 207 age-matched patients with irritable bowel syndrome (IBS) as controls. Cases and controls were followed by the same gastroenterologists of tertiary referral clinics in Tehran, Iran. The questionnaire focused on the date of the first acquisition of home refrigerator and freezer. Data were analysed by a multivariate logistic model. The current age was in average 34 years in CD cases and the percentage of females in the case and control groups were respectively 48.3% and 63.7%. Patients were exposed earlier than controls to the refrigerator (X2 = 9.9, df = 3, P = 0.04) and refrigerator exposure at birth was found to be a risk factor for CD (OR = 2.08 (95% CI: 1.01–4.29), P = 0.05). Comparable results were obtained looking for the exposure to freezer at home. Finally, among the other recorded items reflecting the hygiene and comfort at home, we also found personal television, car and washing machine associated with CD.

Conclusion

This study supports the opinion that CD is associated with exposure to domestic refrigeration, among other household factors, during childhood.

 

[kiny]

I know it's an old study but it's actually one that makes sense to me.

They're two theories that are complete opposites, the hygiene theory and the cold chain theory.

The hygiene theory proposes that increased hygiene is predisposing with crohn's disease.

The cold chain theory proposes that refridgerators (this is the hardest word to spell in the English language for me) increase bacterial load of food, and people with issues of bacterial clearance (like people with crohn's disease) will have issues with lots of food coming from refridgerators because the bacterial load is high. People with crohn's disease have issues clearing bacteria in general, lymphatic drainage issues, issues through NOD2 and ATG16L1 mutations, vitamin D status, etc.

It's a theory that actually makes some sense, unlike many others that have so many flaws.

 

[rollinstone]

Heaps interesting, wonder if it would or could be linked to the hygiene hypothesis in regards to third world countries mentioned, most of which don't have the luxories of fridges.

 

[kiny]

Not sure, it rises very fast in countries in the Middle East and Asia, but these demographics now have all access to refrigerators, much more so than in the past.

The hygiene hypothesis to me is the reverse of the cold chain hypothesis, hygiene hypothesis proposes low bacterial load in the environment to be responsible, the cold chain hypothesis proposes high bacterial load from refrigerators, specifically psychrotrophic bacteria that thrive there.

Maybe someone who has lived in the Middle East or knows about the Middle East more than me can say if there is more hygiene or simply more use of refrigerators.

Does the hygiene hypothesis still make sense when people from India with low crohn's disease come to the West and within a couple of years they get crohn's disease, are these people suddenly more hygienic in a couple of years that it would this strongly impact their immune system, seems a bit far-fetched to me, they would immediately be exposed to refrigerated food though, even if they themselves have no refrigerator.

 

[kiny]

posted in wrong section sorry, can anyone move this to the multimedia section please, thank you

 

[kiny]

nm

 

[kiny]

Thanks whoever moved this thread btw ~

 

[Mark in Seattle]

Does the hygiene hypothesis still make sense when people from India with low crohn's disease come to the West and within a couple of years they get crohn's disease, are these people suddenly more hygienic in a couple of years that it would this strongly impact their immune system, seems a bit far-fetched to me, they would immediately be exposed to refrigerated food though, even if they themselves have no refrigerator.

Thank you for pointing that out. This is what I have been wondering, almost exactly. Not so much fixated on the hygiene hypothesis, but very curious indeed as to what drives the contraction of IBD amongst immigrants.

I would love to get my hands on the full text of a decent cold chain text. The abstract doesn't do much at all to convince me of anything. I need to understand how the bacterial load increase occurs via refrigeration. I thought I recalled cold chain to be a theory of some elusive bacterium which somehow flourished in the refrigerator; maybe I'm off.

I know there are ice worms in the polar caps that live 20 feet under the ice. Not sure what would happen if you ate those little guys....I may be diverging slightly....

 

[Mark in Seattle]

Oh you did provide the full text, I overlooked it initially; how excellent you are!

Here is what I find to be the key portion of the text:

The cold chain hypothesis assumes that CD results of the chronic exposure to bacteria able to grow at low temperature and known as psychrotrophic bacteria. Among these bacteria, Yersinia species may be seen as the best candidates for several reasons. Firstly, many authors reported cases where CD developed after a documented infection by Yersinia species. More recently, a Scandivanian group confirmed these individual reports at the population level, showing that CD is more frequent in the years following a documented Yersinia infection [42]. Secondly, mesenteric lymph node mononuclear cells of CD patients have been shown to have an increased proliferative response toward Yersinia antigens [43]. Thirdly, at least two groups have independently found Yersinia species in CD lesions [44], [45]. Finally, we have recently shown that mice invalidated for CARD15/NOD2 are characterised by an abnormal response after oral infection by Yersinia pseudotuberculosis [46]. Altogether, these data support the cold chain hypothesis and suggest pursuing investigations.

OK, so why do we hear virtually nothing about the cold chain hypothesis? I need to look into this further and see what other arguments are out there.

 

[Mark in Seattle]

http://www.webmd.com/ibd-crohns-disease/crohns-disease/news/20031211/does-cold-food-cause-crohns

.By Salynn Boyles
WebMD Health NewsReviewed by Charlotte E. Grayson Mathis, MDDec. 11, 2003 -- Modern refrigeration is justifiably heralded as one of the most significant health advances of the 20th century, but French researchers say it may also be the cause of one malady -- the mysterious bowel disorder known as Crohn's disease.


It is just a theory, but they say the evidence points to food refrigeration as the catalyst for a dramatic increase in Crohn's cases. It is known that genetic predisposition plays a role in Crohn's disease, and environmental factors such as smoking and diet have also been implicated. But while theories abound, no single cause has been identified.

"Cold Chain Hypothesis"

At least half a million Americans suffer from Crohn's disease, an inflammatory bowel disease that causes abdominal pain, diarrhea, and potentially, bleeding and anemia.


In a paper published Dec. 13 in the journal The Lancet, widely respected Crohn's researcher Jean-Pierre Hugot, MD, and colleagues from Paris' Hospital Robert Debre point out that the arrival of mechanical refrigeration in kitchens throughout the industrialized world paralleled the rise in diagnosed cases of Crohn's disease.


They implicate specific bacteria that thrive at low temperatures as the potential cause of Crohn's disease in genetically susceptible people, and they dub this theory the "cold chain hypothesis."


"The cold chain hypothesis suggests that psychotropic bacteria such as Yersinia and Listeria -- commonly found in beef, pork, chicken, sausages, hamburgers, cheese, and lettuce -- contribute to the disease," Hugot noted in a news release.

Toothpaste and Corn Flakes

Crohn's expert David Sachar, MD, says it is widely believed that environmental changes during the 20th century have played a role in the rising prevalence of the disorder. He tells WebMD that the observation has led to some provocative, but hard to prove, hypotheses, such as those linking Crohn's disease to such components of modern life as toothpaste and corn flakes.


Sachar says Hugot and colleagues make a good case for their theory that food refrigeration is the environmental catalyst researchers have been looking for, and adds that there is no group of researchers with better credentials to make such a claim.


The director emeritus of the gastroenterology department at New York's Mount Sinai School of Medicine, Sachar says while it is clear the researchers are "in the right church," it is not clear that they are "in the right pew."


"Their suggestion that the modern industrialized environment has introduced new bacteria into the food supply is not in itself novel," he says.


"What is novel is their argument that it is refrigeration in particular that has promoted the emergence of causative bacteria in food. This is certainly a proposal worthy of serious consideration, but it may be no more plausible than parallel hypotheses linking the development of pathologic lesions to ingested small particles -- whether from food additives or packaging or cooking utensils or, for that matter, even from toothpaste."

Implications

If the hypothesis is proven, investigators say it could have implications for future Crohn's disease research. But nobody is suggesting that Crohn's patients should, or even could, avoid foods that have been refrigerated.


"(Refrigeration) has produced many benefits for western societies, including the prevention of enteric infections, allowing more people access to a well-balanced diet," Hugot and colleagues wrote. "These advantages clearly outweigh the putative risks discussed here."

 

[Mark in Seattle]

My gut hurts so bad any more, all I can think about is what the environmental variable(s) can be. I am really glad that kiny posted this; I read this study years ago and never really thought much about it after that because nobody is following up on this research. I emailed Dr. Hugot just the other day, and he was actually kind enough to reply to me, stating this is not a popular hypothesis for other researchers (which is of course obvious given the complete absence of research papers on the subject) and that he is still plugging away on this hypothesis, and that he just finished a paper which will be published in a medical hypotheses book some day. It seems that he feels that this hypothesis fits with the data, but needs proof. He plans on continuing to work on trying to demonstrate the hypothesis in the next few years in his lab. I'm glad someone is trying to keep this hypothesis alive.

If I move to a southern lattitude and learn to grow food, hunt, and raise livestock, perhaps I could dispense with the fridge and test the hypothesis myself. Seems like that's kind of what it's coming to for me.

 

[kiny]

thanks for talking to him

 

[KWalker]

Thanks for posting the link but it seems like people are starting to make crohns sound like cancer in the sense that people are starting to suggest everything may be a potential cause for crohns. Every single house within developed countries has at least one fridge so why doesn't every single person within those homes have crohns?

And what's next? the type of light bulbs you use can have an affect on crohns?

 

[Mia E]

I'm sure it was the more well off people who were able to afford the refrigerator, tv etc.
Maybe being rich is a risk factor? or the food rich people eat? or visit? too many confounding variables for my liking!

p.s. i'm being cynical as I haven't read the full text!

 

[kiny]

Every single house within developed countries has at least one fridge so why doesn't every single person within those homes have crohns?

Well ok,

Why does half of the world have helicobacter pylori and only a fraction get sick from it.

Why did some white fathers spend years amongst leprosy patients and never got leprosy, why did some get leprosy after a couple of days.

Why does the overwhelming majority of people having the CARD15/NOD2 mutation not have crohn's disease.

It's the same question you're asking. Why, because some people get sick and others don't.

People with crohn's disease have issues with bacterial clearance, refridgerated food sometimes harbours listeria, salmonella, yersinia, etc. Looking at pathogens that are able to penetrate the mucosa and cause transmural disease like in crohn's disease is a very worthwhile idea.

Cold chain hypothesis, something in the food chain, and zoonotic pathogens are reasonable explanations, if anyone can come up with others you're welcome to share, but within the realm of causation these are reasonable explanations.

 

[kiny]

Maybe being rich is a risk factor?

Being wealthy is a risk factor for crohn's disease, it might be related to rich people living in an urban setting which has more people with crohn's disiease, even in developing nations.