Abstract： Objective To evaluate the relationship between the trend of glutamyl transpeptidase(GGT)change and newly developed metabolic syndrome(MS),and to explore the relationship between GGT and MS.Methods The study was a prospective cohort study,with baseline data sourced from the Beijing subcenter population of the"REACTION"study.A total of 6482 non-MS subjects was enrolled as the study subjects,and divided into four groups using the quartile method based on GGT level:G1(GGT<14.2 U/L,n=1613),G2(14.2≤GGT<18.6 U/L,n=1602),G3(18.6≤GGT<26.1 U/L,n=1639)and G4(GGT≥26.1 U/L,n=1628)group.Follow up was conducted 3.2 years later to analyze the correlation between baseline GGT and the trend of GGT changes with the risk of new MS.Results Baseline GGT was a risk factor for newly diagnosed MS.Compared with G1 group,the relative risk(RR)(95%CI)of newly diagnosed MS at follow-up in G2,G3,G4 group were 1.480(1.220～1.780,P<0.01),2.090(1.750～2.490,P<0.01),and 2.800(2.360～3.320,P<0.01),respectively.The increase in GGT is a risk factor for newly diagnosed MS during follow-up in this population.Compared with the group with decreased GGT,the RR(95%CI)of newly diagnosed MS during follow-up was 1.410(1.320～1.510)(P<0.01)in the group with increased GGT.In stratified subgroup analysis,the incidence of new-onset MS was[1.650(1.410～1.940)vs 1.510(1.310～1.750),P<0.01]respectively in female and middle-aged people in the GGT increase group compared with the GGT decrease group.There was no statistically significant difference in the risk of developing new MS in both male and elderly populations between the GGT increasing group and the decreasing group(P>0.05).Conclusions The increase in GGT is a risk factor for newly diagnosed MS,especially in female and middle-aged populations.