To explore association between gamma-glutamyl transferase and type 2 diabetes using a real-world study and mendelian randomization analysis

Clinical Evidence of the Relationship Between Alanine Aminotransferase and Diabetic Kidney Disease

Aim

Multiple studies have investigated the association between alanine aminotransferase (ALT) and diabetes mellitus (DM); however, only a few studies have specifically examined the relationship between ALT and diabetic kidney disease (DKD). This study aimed to investigate the relationship between ALT and DKD using clinical data.

Methods

A cross-sectional study was conducted on 668 individuals that included non-DM (N=281), DM without DKD (N=160), and DKD (N=227) patients. A generalized additive model (GAM) was used to examine the dose-response relationship between ALT and DKD risk. We also analyzed the data from the US National Health and Nutrition Examination Survey (NHANES) 2015-2018 using the same statistical methods; 4481, 1110, and 671 individuals were included in the non-DM, DM without DKD, and DKD groups, respectively.

Results

The changes in ALT activity among the non-DM, DM without DKD, and DKD groups showed a similar pattern in both our clinical data and the NHANES dataset. ALT activity increases with the onset of DM, whereas ALT activity decreases when DM progresses to DKD. The GAM revealed a nonlinear U-shaped relationship between ALT and DKD risk in the two datasets, and the lowest range of ALT was 40-50 IU/L. Both lower (<40 IU/L) and higher (>50 IU/L) ALT activity were found to be positively associated with DKD risk.

Conclusion

A U-shaped nonlinear association between ALT and DKD was found in our clinical data and NHANES data. DKD risk was increased by both lower or higher ALT activity. To confirm the causality of nonlinear relationship, larger prospective studies or Mendelian randomization analysis are required.

Association between serum gamma glutamyl transferase and fasting blood glucose in Chinese people: A 6-year follow-up study

AIMS/INTRODUCTION

In this study, we aimed to investigate the relationships between gamma-glutamyl transferase (GGT) and fasting blood glucose (FBG) during a 6-year follow-up study of participants, and to determine whether GGT is a risk factor for FBG.

MATERIALS AND METHODS

A total of 1,369 individuals from the health examination survey in the urban area of Xuzhou, central China, were followed up for 6 years. The patients were divided into four groups based on their baseline GGT levels (in quartiles). The one-way analysis of variance (anova) method was used to compare the differences between the variables and baseline. The relationship between GGT and FBG levels was investigated using repeated measurements anova.

RESULTS

The grouping of baseline GGT levels affected the changes in blood glucose during the 6-year follow-up study. In the GGT quartile subgroups, the annual mean increase in FBG levels showed a positive relationship with baseline GGT levels. This trend was even more aggregated in the highest baseline GGT group. Interactions among time course, baseline FBG and GGT groups in different participants together affected the change of FBG levels during the follow-up period. The repeated measures anova suggested that different baseline GGT groups were still significantly associated with increased FBG levels. GGT is a risk factor that affects FBG levels(P < 0.001).

CONCLUSIONS

The annual mean increase in FBG levels showed a positive relationship with baseline GGT levels. Higher baseline GGT levels resulted in a faster annual mean increase in FBG. Thus, GGT can be used for the early detection of FBG-related disorders of glucose metabolism for clinical application.