Dig Dis Sci  1989 Dec;34(12):1841-54 

A meta-analysis of the role of smoking in inflammatory bowel disease.

Calkins BM.

Department of Epidemiology and Biostatistics, School of Medicine, Case Western

Reserve University, Cleveland, Ohio 44106.

A relationship between not smoking and ulcerative colitis has been examined in

all English reports. This paper evaluates the ulcerative colitis/nonsmoking and

the Crohn's disease/smoking association by meta-analysis and against causality

criterion for chronic diseases. A review of the literature, meta-analysis of

selected studies, and assessment of causality criterion all suggest that not

smoking and ulcerative colitis and smoking and Crohn's disease are consistent

with a causal relationship. It is not inconceivable that tobacco may contain

some substance beneficial to ulcerative colitis patients. Identification of the

specific product in tobacco producing a beneficial effect would be a prudent

next step in the study of this association. In spite of the findings of this

review and analysis, the author finds no justification for health care providers

to change the Surgeon General's recommendations on smoking or tobacco use for

ulcerative colitis patients specifically.