Objective  To investigate the content of plasma folic acid (FA) and the gene polymorphisms of methylenetetrahydrofolate reductase (MTHFR C677T) and methionine synthase (MS A2756G) among migrants and non-migrants in Changzhi city of Shanxi province, and to provide evidences for further research.

  Methods  We recruited 80 migrants and 108 non-migrants without abnormal findings in gastroscopy examination at a hospital in Changzhi city from May 2014 to June 2015. Plasma FA was detected with enzyme-linked immunosorbent assay (ELISA) and MTHFR and MS gene polymorphisms were analyzed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) among the participants.

  Results  There was a significant difference in plasma FA level between the migrants and non-migrants (P = 0.006). Among the migrants, the plasma FA level differed significantly by gender, age, and whether drinking alcohol (P < 0.05 for all); while, among the non-migrants, FA level differed significantly by blood type (P < 0.05). There were significant differences in plasma FA levels between the migrants and non-migrants for the participants aged > 60 years, with the body mass index (BMI) of < 18.5 kg/m², non-smokers, and non-alcohol drinkers (P < 0.05 for all). The MTHFR and MS genotypes and allele frequencies were different significantly between the migrants and non-migrants (all P < 0.05).

  Conclusion  The plasma FA level is different between migrants and non-migrants and various subgroups of the two populations. The distribution of MTHFR and MS gene polymorphisms are also significantly different between the two population groups.