11 October 2007
smoking good?... or smoking bad?
The relationship between smoking and the form of IBD that was manifested in siblings with a genetic predisposition was determined and explained in the article entitled “In siblings with similar genetic susceptibility for inflammatory bowel disease, smokers tend to develop Crohn’s Disease and non-smokers develop ulcerative colitis” by S Bridger, J C W Lee, I Bjarnason, J E Lennard Jones, and A J Macpherson. It was found that CD was more commonly developed in the siblings that smoke, especially in women. Furthermore, it was also determined that the smokers in the study had less of a chance of developing UC. I found this article interesting because it shows an extreme link between “tobacco usage inhibiting UC and enhancing CD pathogenic mechanisms.” It was also stated that “the influences of tobacco on disease pathogenesis are on the immunopathogenic mechanisms at disease onset as opposed to cumulative damage” due to the fact that the manifestation was effectively reversed when the subjects were no longer smoking for a year. Also, it was discussed that there are many diseases that are associated with tobacco smoke, however the mechanisms are not known. It is known that smoking has “multiple effects on many immune and inflammatory functions.” The need for further studies such as the rodent model presented in this article is evident.
Subscribe to:
Post Comments (Atom)
6 comments:
Your title "smoking good? or smoking bad?" is misleading. Smoking is bad. Period. Even if smoking does reduce the risk of UC (and pre-dispose to Crohn's disease), I can't see any scenario in which smoking would benefit a patient's health overall. Smoking causes or increases the risk for so many other diseases and complications, it would never be recommended as a way to treat or prevent UC. It may be worth studying this phenomenon to determine what about tobacco prevents UC, and figure out a healthier way to get that benefit.
This week, Dr. Charles Bernstein from the University of Manitoba talked at U. of Colorado about the epidemiology of IBD. He had very strong data that smoking--even passive smoking!--is a major risk factor. Another, that is very interesting: poverty protects against IBD. A map of Winnipeg showing where every patient with IBD lives is identical to one that shows the richest neighborhoods. He wondered whether the "hygiene hypothesis" was involved; and whether having intestinal parasite protects the poor from IBD. Incidentally, he said that, pretty much, everything that's true for UC is also true for CD.
The paper that we read in our class (Gut 2002;51;21-25) is interesting because it demonstrated that in siblings (not identical twins) the sib who smoked developed Crohn's disease whereas the twin that didn't smoke developed ulcerative colitis. The article was very clear that smoking doesn't "cure" Crohn's disease and that it is not being thought of as a treatment therapy, but that there might be something in cigarette smoke (not the nicotine-that's been demonstrated) that pushes a person with the right genetic background, towards UC.
The hygiene hypothesis seems to hold true for IBD...overall a much smaller portion of a rural community (lack of running water, lack of hot water, large families living in small places) develops IBD. Interestingly, it also seems that the same holds true for appendectomies...that often it's the transition from a high fiber (course) diet to a more refined diet that leads to appendicitis (which has been looked at and disregarded as a possible treatment option for IBD). Just an interesting correlation!! (Burkitt: the aetiology of appendicitis) (Gut, 2004;53;351-354)
This is very interesting, I am a veterinarian and it seems as though I see more IBD with each passing year. I have not systematically investigated this observation so it may just be me, but here is a thought: deworming is a standard part of preventive care and more and more people are keeping their cats indoors only. I think both of these things are benficial for other reasons (limiting zoonoses) so I am not about to stop receommending both but it is food for thought...
I am very interested in the hygiene hypothesis as explanatory of immune-related conditions. I first studied it in association with asthma and found that it made intuitive sense - given a rural background myself and no history of allergies in anyone related to me.
But, the hygiene hypothesis makes less intuitive sense to me in the context of IBD. Isn't it possible that the many variables that partially define differences between rural and urban or lower income and higher income are confounding?
A couple of possibilities:
While eating in a rural setting might be accompanied by more dirt per pound of food (fresh veggies and what-not) the way the food is prepared is generally very different between rural and urban settings. In rural settings if one is on the poor side one likely is more engaged with the food one eats in that there is a string of steps and procedures with which one is involved when preparing a meal. Anyone who has picked greens fresh from the field for a salad knows this. Does starting with a whole food (not the store) and bringing it to the table result in a substantively different meal experience? Is it better food? Is it prepared in a way that is more amenable to gastronomic enjoyment? Is it more likely to involve dinner companions? It is more restricted to what is produced locally with less from distant producers?
Contrast this with food as it is ingested in more urban settings. Eating out in cities is less expensive (generally) than eating out in less urban settings. Where time is the limiting factor in meal preparation one may be more likely to purchase meals rather than make meals.
Is it possible that there is some important difference in the eating experience that is different and that could account for more IBD in urban/richer areas? I think I will have a glass of wine while I prepare dinner and ponder this!
Post a Comment