Professor Jack Satsangi and his colleagues Dr Marian Aldhous and Dr Richard Russell have been engaged in an active research programme concerning smoking and IBD. Two of their studies have been looking at first: whether the amount you smoke over a lifetime has a bearing on IBD and second: is there a link between having a parent who smokes and  being diagnosed before the age of 16.

In the first study, 800 patients completed questionnaires on whether they smoked, when they started smoking, when they stopped and how much they smoked.

The research found that among patients with Crohn’s, the more these patients smoked, the higher up in the gut the Crohn’s was likely to be. The heavier smokers were likely to have Crohn’s higher up in the stomach, or small bowel, compared to those who stopped smoking or were light smokers, who were more likely to have colonic disease, ie disease lower in the gut.

The findings also replicated earlier findings that in people with UC, smoking seems to have a protective effect. In fact the survey revealed that the heavier the smoker the healthier the colon compared to lighter smokers.

Professor Satsangi says: “This relationship between the site of Crohn’s Disease and smoking is very interesting, and the findings novel. In a way, colonic CD in it’s relationship to smoking is behaving more like UC in that it’s the lighter smokers with colonic disease: the heavier smoker gets gastric and duodenal Crohn’s higher up in the stomach and then small bowel disease; so it’s almost a gradient down the gut: the higher smokers get the disease higher up.

The second of the two studies looked at IBD and the effects of parental smoking, as well as environmental factors such as breastfeeding, immunisation, and atopy, which is a predisposition to eczema, asthma and food allergies. Professor Satsangi and his team were interested in in the increasing numbers of children under 16 being dxd with UC and CD in Scotland and wanted to find out whether there were environmental factors in early life or while the child was in the womb that might affect the development of IBD.

The study matched children with IBD against ‘controls’ – healthy children of the same age – using data from questionnaires about whether the children had been exposed to smoking from either parent at birth or while the child was in the womb. What the scientists found was that if one or parents were smokers, their child was more likely to have IBD than if the parents were non-smokers: 54% of the children had parents who smoked, compared to 29% of the control group. Looking at whether it made a difference if the smoker was the mother or the father, the study found no difference.

Although a small study, the results on smoking are particularly interesting. Dr Russell also found that in the Crohn’s patients, a personal history of asthma, a history of food allergy and a predisposition to eczema, asthma and food allergy were all more common than in healthy children.

There was no difference between the two groups when it came to the MMR vaccination.

Report from Spring 2005 NACC newsletter.