Association of liver enzymes levels with fasting plasma glucose levels in Southern China: a cross-sectional study

OBJECTIVE: According to several studies, liver enzymes levels are associated with fasting plasma glucose (FPG) levels. However, the association stratified by body mass index (BMI) remains to be elucidated, especially in Southern China. Therefore, the aim of this study was to investigate the correlation between liver enzymes levels and FPG levels stratified by BMI in Southern China. DESIGN: Cross-sectional study. PARTICIPANTS AND SETTING: 3056 individuals participated in real-time interviews and blood tests in Southern China. Participants were divided into three groups (underweight, normal weight and overweight or obesity) based on BMI cut-offs. MAIN OUTCOME MEASURED: Partial correlation analysis was performed to investigate the relationship between FPG levels and liver tests. Multivariate logistic regression analyses were applied to calculate the adjusted ORs for FPG levels based on liver enzymes levels. RESULTS: There was no association between liver enzymes and FPG either in the underweight group or in the normal weight group; however, a significant correlation was observed in the overweight or obesity group (alanine transaminase (ALT), p<0.01; aspartate aminotransferase (AST), p<0.05). After adjusting for confounding factors, the highest tertiles of ALT still remained significantly positively related to FPG levels in the overweight or obesity group, with an OR of 2.205 (95% CI 1.442 to 3.371) for the 5.56≤FPG<7.00 mmol/L vs the FPG<5.56 mmol/L group and with an OR of 2.297 (95% CI 1.017 to 5.187) for the FPG≥7.00 mmol/L vs the FPG<5.56 mmol/L group, but this correlation was not found for AST. CONCLUSIONS: The association of liver enzymes levels with FPG levels differed based on different BMI cut-offs. ALT levels were significantly positively associated with FPG levels in the overweight or obesity group, but not in the other two groups; AST levels were not associated with FPG levels in any group.