Table 1.

Reasons for study exclusion

Studies	Reasons
Glas et al[31], Török et al[32]	Data overlapped those of another article[17]
Cooney et al[33]	Data overlapped those of another article[8]
Weersma et al[34], Weersma et al[35]	Data overlapped those of another article[26]
Franke et al[36], Franke et al[37]	Data overlapped those of another article[5]
Fisher et al[38], Wtccc et al[40], Parkes et al[43], Yamazaki et al[45]	Other SNPs rather than rs2241880 SNP of ATG16L1 were analyzed
Beckly et al[39], Barrett et al[41], Libioulle et al[42], Raelson et al[44], Kugathasan et al[46]	Data could not be extracted