THE ASSOCIATION BETWEEN ALANINE AMINOTRANSFERASE (ALT) AND SERUM URATE IN BRAZILIAN YOUNG ADULTS

Introduction

Serum urate (SU) has been associated with cardiometabolic risk factors in observational studies, but causal roles remain unclear. The alanine aminotransferase (ALT) is a surrogate marker of nonalcoholic fatty liver disease (NAFLD), which is deeply associated with metabolic disorders. The aim of this study was to assess the association between ALT and SU in young adults.

Methods

At the 22-year follow-up of the 1993 Pelotas (Brazil) birth cohort, ALT was evaluated using kinetic UV IFCC ALT/GPT LIQUIFORM kit and converted into logarithm for regression analysis. SU was evaluated by enzymatic-colorimetric assay. The co-variables taken into consideration were waist circumference, body mass index, systolic and diastolic blood pressures, triglycerides, glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting period, smoking status, excessive alcohol consumption (>8 points in the Alcohol Use Disorders Identification Test-AUDIT), and physical inactivity. Sex-stratified linear regressions have been performed due to the significant interaction between ALT, SU and sex (p<0.001). A p-value less than 0.05 was considered statistically significant.

Results

The sample comprised 1638 (47.6%) men and 1801 (52.4%) women aged 22.6 (±0.34) years old. Median (IQR) ALT (U/L) was 18 (13-26) in men and 13 (10-18) in women. Mean (±SD) SU (mg/dL) was also higher in men (5.2±1.2 vs. 3.9±1.1). The exponential means of ALT (U/L) according to the SU tertiles are exposed in table 1. A significant linear tendency of ALT increasing according to the SU tertiles was observed in women (p<0.001), but not in men (p=0.081).

Conclusions

ALT was positively associated with SU in women, even after adjusting for potential confounders. This finding suggests that uric acid is associated with metabolic disorders since early adult age. Nevertheless, further prospective studies are necessary to better understand the association between SU and NAFLD.