Association Study Between Dynamic Changes In Liver Aminotransferases And Metabolic Syndrome

Objective: Some researches found hepatic metabolism has been demonstrated to be closely related to Metabolic syndrome(MetS),and liver aminotransferases,such as alanine aminotransferase(ALT)and aspartate aminotransferase(AST),have been reported to be associated with MetS.The objective of this study was to research the dynamic change in liver Aminotransferases and the occurrence of MetS.These findings provided a basis for using the dynamic changes in ALT/AST levels to predict the development of MetS.Methods: We analysed the associations between the changes of ALT/AST level trends and MetS among 1119 subjects who underwent consecutive annual health check-ups during 2010~2013.We divided the subjects into two groups,MetS and MetS-free,based on whether they developed MetS during the follow-up period.We compared the average annual changes in the ALT and AST levels in the two groups.We used a linear mixed-effects model,implemented in R,to analyse the associations between the changes of ALT/AST level trends and MetS.We established single factor and multiple factors Logistic regression in SPSS17.0 to analyse the association between the average annual changes in the ALT and AST levels and the occurrence of MetS.Results: Of the 1119 total subjects,80(7.15%)were diagnosed with MetS during the follow-up period.The MetS group had higher annual rates of change in the two liver markers than did the MetS-free group(ALT:Z=-3.85,P=0.000;AST:Z=-3.96,P=0.000).The participants who developed MetS in the different years had significantly greater annual rates of change than did members of the MetS–free group.The annual rates of change of ALT who developed MetS in 2010 and 2011 was significantly different from the MetS-free group(P<0.008);the annual rates of change of AST who develop MetS in 2012 was also significantly different from the MetS-free group(P<0.008).In the linear mixed-effect model of logALT,the average level of logALT was 1.2701mmol/L(1.258~1.282,P<0.001)for a 37(the median of the baseline age)year old Met S-free subject at baseline.The average level of logALT among subjects developed MetS was 0.156 mmol/L(0.101~0.211,P<0.001)higher than that of the MetS-free subjects.The logALT value of the MetS-free subjects increased by 0.0034 mmol/L(0.001~0.005,P<0.001)per 1-year increase in baseline age.The interaction between Met S status and baseline age was statistically significant,and the logALT value of subjects who had developed MetS decreased by 0.0041 mmol/L(-0.006~-0.002,P=0.005)per 1-year increase in baseline age due to this interaction.Consequently,the logALT level of younger subjects who developed MetS was higher than that of older subjects.A significant interaction effect between measured time points and MetS status were also identified,and for this interaction term,the level of logALT among subjects who developed MetS increased by an average of 0.0307 mmol/L(0.004~0.058,P<0.05)with each additional measured time-point,while the ALT levels among MetS-free subjects remained fairly constant during the follow-up period.In the linear mixed-effect model of logAST,the mean value of logAST was 1.3159 mmol/L(1.308~1.324,P<0.001)for a 37(the median of the baseline age)year old subject in the MetS-free group at baseline.The logAST value of subjects who developed MetS was 0.0426 mmol/L(0.012~0.074,P=0.008)higher than that of the MetS-free subjects.The logAST level for MetS-free subjects increased by an average of 0.0023 U/L(0.001~0.003,P<0.001)per 1-year increase in baseline age.The logAST level for MetS-free subjects decreased by an average of 0.0049U/L(-0.009~-0.001,P=0.002).Although the significant interaction effect between baseline age and MetS status resulted in a reduction of approximately 0.0019 U/L(-0.004~0.000,P=0.017)in the logAST level when baseline age increased by 1 year among the subjects developed MetS,the logALT level of older subjects who developed MetS was still little higher than that of younger subjects.In single factor Logistic regression,the increase of baseline age,ALT baseline level and the annual rates of change of ALT and AST were the risk factors of MetS.In multiple factors Logistic regression,baseline age(OR=1.042,1.025~1.059,P<0.001),the baseline level of ALT(OR=1.037,1.022~1.052,P<0.001)and the annual rates of change of ALT(OR=1.108,1.076~1.141,P<0.001)were related to the occurrence of MetS.Conclusion: The levels of ALT and AST were significantly higher among the subjects who developed MetS before they diagnosed MetS and ALT and AST levels demonstrated an increasing trend in subjects who developed MetS.The average annual change of ALT was the risk factor of the occurrence of MetS.We should pay more attention to hepatic metabolism disorder and the occurrence of MetS when the ALT and AST levels presented a rising tendency though the liver aminotransferases levels did not exceed the normal reference value.