Thinking beyond Opisthorchis viverrini for risk of cholangiocarcinoma in the lower Mekong region: a systematic review and meta-analysis

Table 4 Significant relationships between risk factors for CCA

	Risk Factors
Increased risk of CCA	alcohol x smoking [23, 26] alcohol x fermented fish [23] GSTM1 x O. viverrini antibody [23] GSTT1 x alcohol [23] MTHFR x raw fish [24, 27] MTHFR x fermented or processed meat [24] MTHFR x O. viverrini antibody [27] male x O. viverrini antibody [22, 46] XRCC1 x OGG1^a [26] XRCC1 x smoking [26] OGG1 x smoking [26]
Decreased risk of CCA	CYP1A2 x male [29] CYP1A2 x smoking [29] GSTM1 x OGG1 [30] XRCC1 x OGG1^a [26]

Individual gene risk information in Table 3
^aXRCC1 and OGG1 genes both exhibit multiple polymorphisms, and depending on the combination of polymorphisms present in the individual, the interaction between XRCC1 and OGG1 may increase or decrease risk

ISSN: 2049-9957