Table 1.

Core characteristics of studies included in the meta-analysis [9,10,11,12,13,14,15,16,17,20].

Studies	Year	Country	Baseline		Study Characteristics			IBD Development (Outcomes)		Literature Quality †
			Age	Gender	Cohort Design	Follow-Up (Year)	Sample Size	CD	UC
Moon, J. M. et al. [20]	2020	Korea	50	Both	Retrospective	7.3	14,060,821	977	-	8
Mendall, M. A. et al. [9]	2019	Denmark	19	Male	Prospective	38	377,957	1523	3323	9
Jensen, C. B. et al. [10]	2018	Denmark	46	Both	Prospective	38	316,799	1500	2732	7
Mendall, M. et al. [11]	2018	Denmark	30	Female	Prospective	6	74,512	137	448	8
Kuwahara, E. et al. [14]	2017	Japan	42	Both	Retrospective	2	39,554	-	8120	9
Flores, A. et al. [16]	2015	U.S.A.	40	Both	Retrospective	5	581	297	284	8
Melinder, C. et al. [17]	2015	Sweden	18	Male	Prospective	4	240,984	986	1878	9
Khalili, H. et al. [12]	2015	U.S.A.	34	Female	Prospective	18	111,498	153	229	8
Harpsøe, M. C. et al. [13]	2014	Denmark	30	Female	Retrospective	11	75,008	138	394	8
Chan, S. S. et al. [15]	2013	10 European countries	52	Both	Prospective	5.1	300,724	75	177	9

^† Newcastle-Ottawa scale; IBD—Inflammatory bowel disease; CD—Crohn’s disease; U.C.—Ulcerative colitis.