Smoking and IBD risk (case-control. Sweden)
Childhood passive smoking and UC risk (case-control. USA)
Smoking and UC risk (case-control. USA)
Smoking and IBD risk (case-control. Israel)
Smoking and IBD risk (case-control. Spain)
Smoking and CD risk (case-control. Italy)
In siblings with similar genetic susceptibility for inflammatory bowel disease, smokers tend to develop CD and non-smokers develop UC (UK)
Smoking and UC risk (case-control. Australia)