Patients' perspectives on smoking and inflammatory bowel disease: An online survey in collaboration with European Federation of Crohn's and Ulcerative Colitis Associations

Table 3 Perceived effect of smoking on inflammatory bowel diseases based on type of diagnosis

Questionnaire items	Crohn’s disease	Ulcerative colitis	P value1
Perceived impact of cigarette smoking on disease activity
Significantly worsened	12/279 (4.3)	2/191 (1.0)	< 0.001
Moderately worsened	209/279 (74.9)	63/191 (33.0)
No impact	27/279 (9.7)	12/191 (6.3)
Moderately improved	25/279 (9.0)	58/191 (30.4)
Significantly improved	6/279 (2.2)	56/191 (29.3)
Perceived impact of using alternative smoking products on disease activity
Significantly worsened	4/211 (1.9)	12/187 (6.4)	0.004
Moderately worsened	31/211 (14.7)	14/187 (7.5)
No impact	146/211 (69.2)	118/187 (63.1)
Moderately improved	23/211 (10.9)	28/187 (15.0)
Significantly improved	7/211 (3.3)	15/187 (8.0)

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.