Smoking increases the risk of extraintestinal manifestations in Crohn's disease

Table 1 Patient characteristics at first diagnosis and during follow-up n (%)

		All patients	Crohn's disease	Ulcerative colitis	P value
		n = 257	n = 161 (62.6)	n = 96 (37.4)	RR (95%CI)
Sex: male/female		121 (47.1)/136 (52.9)	71 (44.1)/90 (55.9)	50 (52.1)/ 46 (47.9)	0.22
EIM at first diagnosis	At least 1 EIM	91 (35.4)	69 (42.9)	21 (21.9)	< 0.001; RR = 1.96 (1.30-2.95)
New EIM during follow-up	At least 1 EIM	115 (44.7)	79 (49.1)	36 (37.5)	0.07
EIM at any point of observation	At least 1 EIM	163 (63.4)	114 (69.9)	49 (30.1)	0.001; RR = 1.39 (1.11-1.73)
	> 1 EIM	24 (14.5)	18 (15.5)	6 (12.2)	0.39
New EIM during follow-up		94 (36.6)	64 (39.8)	30 (31.3)	0.17
EIM resolved during follow-up		64 (66.0)	47 (64.4)	17 (70.8)	0.63
Disease phenotype at first diagnosis	Crohn's disease		Terminal ileum (L1) 56 (34.8)
			Colon (L2) 40 (24.8)
			Terminal ileum and colon (L3) 61 (37.9)
			Upper GI tract (L4) 2 (1.2)
	Ulcerative colitis			Proctitis 36 (37.5)
				Left-sided colitis 23 (24.0)
				Pancolitis 29 (30.2)1

¹Not applicable in 8 patients. EIM: Extraintestinal manifestation; GI: Gastrointestinal.