Cigarette smoking affects susceptibility to ulcerative colitis.
However, its effects on age at diagnosis, disease extent, and need for surgery are less well defined.
Dr Marian Aldhous and colleagues from Scotland examined these parameters in a retrospective analysis of a large cohort of ulcerative colitis patients.
The team of doctors assessed 499 ulcerative colitis patients, of which 254 were male with a median age of 34 years.
Data were collected on smoking habits, smoking load, age at recruitment, age at diagnosis, surgery, and disease extent.
Colonoscopic and histological data at both diagnosis and follow-up at 5 years were available on 349 patients.
|Regression of disease occurred in 30% of current smokers|
|American Journal of Gastroenterology|
The doctors found that ex-smokers were older at diagnosis than current or nonsmokers.
Before diagnosis, ex-smokers had a higher smoking load than current smokers.
The team used a Cox model for age at diagnosis, with smoking as a time-dependent covariate.
Using this model, the team showed that at any age, ex-smokers were significantly more likely to develop ulcerative colitis than current smokers.
For current smokers at latest colonoscopy, the doctors found that those with extensive disease were the lightest smokers.
The doctors also observed that those with healthy colons were the heaviest smokers.
At 5 years, regression of extensive disease was more frequent in current than ex-smokers or non-smokers.
The team observed that regression of disease occurred in 30% of current smokers vs 8% non-smokers and 5% of ex-smokers.
The team noted that these differences were not maintained over a longer time period.
Dr Aldhous' team concluded, “Smoking habit influences the age at diagnosis and changes in disease extent in ulcerative colitis.”
“Mechanisms are likely to be complex and require further investigation.”