The clinical subclassification of Crohn's disease by phenotype has recently been reevaluated.
Dr Marian Aldhous and colleagues from Scotland evaluated the relationships between smoking habit, age at diagnosis, and disease location.
The investigative team also assessed progression to stricturing or penetrating complications using the Montreal classification.
The investigators evaluated 408 patients, of which 157 were male with a median age of 29 years.
Data were collected on smoking habit, age at diagnosis, anatomical distribution, and disease behavior.
The team reported that follow-up data were available on all patients.
The investigators found that at diagnosis, ex-smokers were older than nonsmokers or current smokers.
|Smokers had less colonic disease than nonsmokers|
|American Journal of Gastroenterology|
Disease location differed according to smoking habit at diagnosis.
The investigators noted that current smokers had less colonic disease than nonsmokers or ex-smokers.
In univariate Kaplan-Meier survival analysis, smoking habit at diagnosis was not associated with time to development of stricturing disease.
The team observed that smoking habit at diagnosis was also not associated with internal penetrating disease, perianal penetrating disease, or time to first surgery.
Patients with isolated colonic disease were slower to develop strictures or internal penetrating disease, and to require surgery.
The team used cox models with smoking habit as time-dependent covariates to further investigate these associations.
The investigators showed that, relative to ileal location of disease, progression to stricturing disease was less rapid for patients with colonic disease.
However, the team observed that this was not independently affected by smoking habit.
Progression to surgery was also slower for colonic than ileal disease location, but was independent of smoking habit.
Dr Aldhous' team concluded, “Smoking habit was associated with age at diagnosis and disease location in Crohn's disease.”
“Disease location was associated with the rate of development of stricturing complications and requirement for surgery.”
“The pathogenic basis of these observations needs to be explained.”