Danish cohort of monozygotic inflammatory bowel disease twins: Clinical characteristics and inflammatory activity

Table 1 Clinical characteristics n (%)

Pair type	Discordant twin pairs					Concordant twin pairs
Status	Co-twin	CD	IBDU	UC	non-IBD GI symptoms	IBD co-twin	IBD index twin
n	52	8	5	31	8	10	10
Males/Females	23/29	2/6	1/4	16/15	4/4	4/6	4/6
Age (yr)	50(26-78)	47 (26-67)	57 (34-77)	49 (32-70)	55 (27-78)	49 (28-68)	49 (28-68)
Age at onset		32 (21-47)	43 (23-73)	35 (20-59)	38 (23-62)	21 (14-29)	23 (11-34)
Age at diagnosis		34 (25-46)	41 (29-72)	34 (17-66)	48 (18-72)	24 (11-37)	31 (21-47)
CPH criteria fulfilled		6 (75)	4 (80)	24 (77)	0 (0)	8 (80)	9 (90)
Disease location
L1 ileal		2 (25)	2 (40)			3 (30)	2 (20)
L2 colonic		3 (38)	0 (0)			1 (10)	1 (10)
L3 ileocolonic		0 (0)	0 (0)			4 (40)	4 (40)
L4 isolated upper disease		0 (0)	0 (0)			0 (0)	1 (10)
B1 non stricturing non penetrating		4 (50)	2 (40)			3 (30)	1 (10)
B2 stricturing		2 (25)	0 (0)			4 (40)	5 (50)
B3 penetrating		0 (0)	0 (0)			3 (30)	2 (20)
P perianal disease		1 (13)	0 (0)			2 (20)	0 (0)
Proctitis			1 (20)	6 (19)
Left sided			0 (0)	9 (29)
Extensive			1 (20)	10 (32)

n denotes the number of participants with the phenotype described in status. IBD: Inflammatory bowel diseases; CD: Crohn’s disease; UC: Ulcerative colitis.

Table 2 Complications, medication and smoking n (%)

Pair type	Discordant twin pairs					Concordant twin pairs
Status	Co-twin	CD	IBDU	UC	non-IBD GI symptoms	IBD co-twin	IBD index twin
n	52	8	5	31	8	10	10
Complications
GI complications1	3 (6)	2 (25)	1 (20)	2 (6)	0 (0)	4 (40)	5 (50)
Extra intestinal manifestations2	5 (10)	3 (38)	2 (40)	12 (39)	2 (25)	2 (20)	6 (60)
Ever surgery	0 (0)	2 (25)	1 (20)	12 (39)	2 (25)	7 (70)	5 (50)
Colectomy	0 (0)	1 (13)	1 (20)	7 (23)	0 (0)	0 (0)	0 (0)
Medication
Ever TNF-inhibitor	0 (0)	2 (25)	1 (20)	4 (13)	0 (0)	1 (10)	1 (10)
Ever glucocorticoids	0 (0)	3 (38)	4 (80)	17 (55)	2 (25)	6 (60)	6 (60)
Ever other immunosupressor3	0 (0)	4 (50)	2 (40)	6 (19)	0 (0)	2 (20)	5 (50)
Ever 5-ASA	1 (2)	5 (63)	4 (80)	22 (71)	1 (13)	5 (50)	6 (60)
Smoking
Never smoker	28 (54)	6 (75)	2 (40)	21 (68)	5 (63)	3 (30)	2 (20)
Current smoker	10 (19)	1 (13)	1 (20)	2 (6)	2 (25)	3 (30)	7 (70)
Former smoker	13 (25)	1 (13)	2 (40)	7 (23)	1 (13)	4 (40)	1 (10)

¹Fistula, adherences, strictures, toxic megacolon, abscess, perforation, colorectal cancer;

²Hepatitis, primary sclerosing cholangitis, autoimmune pancreatitis, uveitis, erythema nodosum, pyoderma gangrenosum, arthritis, aphthous ulcers;

³Methotrexate, azathioprine, and cyclosporine;. n denotes the number of participants with the phenotype described in status. IBD: Inflammatory bowel diseases; CD: Crohn’s disease; UC: Ulcerative colitis.