Table 4.

Extent of discussing with own physician the effect of smoking on inflammatory bowel diseases based on type of diagnosis

Questionnaire items	Crohn’s disease	Ulcerative colitis	P value1
Cigarette smoking
Not discussed	89/412 (21.6)	143/321 (44.6)	< 0.001
Detrimental	286/412 (69.4)	47/321 (14.6)
Possibly beneficial	37/412 (9.0)	131/321 (40.8)
Use of alternative smoking products
Not discussed	43/83 (51.8)	45/72 (62.5)	< 0.001
Detrimental	31/83 (37.4)	8/72 (11.1)
Possibly beneficial	9/83 (10.8)	19/72 (26.4)

The survey had a hierarchical structure, meaning that only patients who answered to certain items could answer to other following questions. For this reason, the denominator for several questions is different. In some cases, the patient did not answer and this can result in a missing value. We have transparently declared in our tables the denominator we have used to calculate the proportion of patients giving certain answers.

¹Fisher’s exact test.