Serum levels of alanine aminotransferase decrease with age in longitudinal analysis

Impact of aging on alanine aminotransferase levels and frailty in chronic kidney disease patients: laboratory-based cross-sectional study in Northwest Ethiopia

Background

Chronic kidney disease (CKD) is a non-communicable progressive condition that leads to a gradual decline in kidney functions, resulting in different complications. Serum alanine aminotransferase (ALT) is an important biomarker for diagnosing liver comorbidities. However, ALT levels in CKD patients could be affected by aging. Despite this challenge, there is a scarcity of data on the effect of aging on frailty and ALT levels in CKD patients in Ethiopia. Thus, this study aimed to assess the impact of aging on serum levels of ALT, the magnitude of frailty, and the associated factors among CKD patients in different age groups.

Methods

A hospital-based cross-sectional study involving 120 CKD patients was conducted in Bahir Dar, Ethiopia. Data were collected using structured questionnaire. Blood pressure, anthropometric parameters, ALT levels, and frailty were assessed according to standard procedures. Data were analyzed using SPSS version 25. Pearson's correlation analysis, multiple linear analysis, and logistic regression analysis were performed to identify predictors of ALT levels and frailty, with a statistical significance level of p < 0.05.

Results

The serum level of ALT was significantly lower in CKD patients aged ≥ 46 years compared to CKD patients aged 18-45 years. The magnitude of frailty in CKD patients aged 18-45 and ≥ 46 years was 8.5% (95% CI: 1.4-15.6) and 34.4% (95% CI: 22.5-46.4), respectively, and was significantly associated with ALT levels. Factors such as age category (AOR: 0.16, 95% CI: 0.04-0.60) and hypertension (HTN) (AOR: 10.16, 95% CI: 1.03-99.90) were significantly associated with frailty.

Conclusion

The serum level of ALT was significantly correlated with age and frailty in CKD patients. Thus, ALT levels can be used as a biomarker for aging and frailty. The age of CKD patients and HTN were factors significantly associated with frailty.

Development and evaluation of percentile curves of serum alanine aminotransferase in older adults: A multi-cohort study

INTRODUCTION AND OBJECTIVES

Age independently impacts alanine aminotransferase (ALT) levels. This study was conducted to develop age- and sex-specific ALT percentile curves among older adults and evaluate their diagnostic performance across two external cohorts.

MATERIALS AND METHODS

We developed ALT percentile curves using data from a reference population aged 50-90 years (n = 20,039). We evaluated diagnostic performance of various ALT thresholds (40 U/L, American College of Gastroenterology [ACG]'s 33 U/L [men] and 25 U/L [women], and the new percentile curves) for infections of hepatitis B virus and hepatitis C virus, metabolic dysfunction associated steatotic liver disease, and excessive alcohol consumption in two external cohorts.

RESULTS

ALT percentile curves declined with age. In men, the 95th percentile decreased from 31.4 U/L at 50 years to 21.7 U/L at 90 years; in women, from 26.1 U/L to 17.8 U/L. The 95th percentile curves achieved the highest Youden's index and area under the receiver operating characteristic (AUROC) across the three thresholds in two external validation cohorts, with the Youden's index and AUROC of 0.141 and 0.571 (95% CI: 0.555-0.586) in external cohort 1, and 0.435 and 0.717 (95% CI: 0.680-0.754) in external cohort 2, respectively.

CONCLUSIONS

The newly proposed ALT percentile curves may serve as a valuable reference for screening liver diseases in older adults.

Scores to predict steatotic liver disease - correlates and outcomes in older adults

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a significant cause of chronic liver disease globally, and the rising prevalence of MASLD is occurring in parallel with the global aging population. The use of non-invasive biomarker tools to rule-in or rule-out hepatic steatosis is important in large epidemiological studies in this field. While the Fatty Liver Index (FLI) is the best validated tool in older adults, not all studies will have the necessary parameters for steatosis identification. This retrospective post-hoc analysis of the ASPirin in Reducing Events in the Elderly (ASPREE) study involved 16,703 Australian adults aged ≥70 years. Using the FLI as the 'gold standard' index, we evaluated the correlation with other indices: the Dallas Steatosis Index (DSI), Framingham Steatosis Index, ZJU index (ZJU), Hepatic Steatosis Index (HSI), Lipid Accumulation Product (LAP), and Visceral Adiposity Index (VAI), as well as age- and sex-adjusted outcome measures including mortality, major adverse cardiovascular events (MACE), atrial fibrillation (AF), and persistent physical disability. Of the non-FLI indices, the DSI and FSI had the highest percentage of participants correctly classified as having MASLD (97.7% and 93.8% respectively). The FSI, LAP, and VAI were associated with MACE. The FSI and FLI were predictive of incident AF. The FLI, DSI, FSI, LAP and VAI were associated with physical disability. No MASLD score was associated with increased mortality. Indeed, MASLD defined by the ZJU and HSI were both inversely associated with mortality. As such, we've demonstrated that the FSI and DSI are the most accurate scores for identifying MASLD in older adults when compared to the FLI as the gold standard. The FSI is associated with MACE, AF, and persistent physical disability, lending support to its use in identifying older persons with MASLD when the FLI is unable to be calculated.

A New Model of Chronic Kidney Disease, Metabolic Derangements, and Heart Failure with Preserved Ejection Fraction in Aging Swine

INTRODUCTION

Chronic kidney disease (CKD) and heart failure with preserved ejection fraction (HFpEF) are more prevalent in the elderly. There is a lack of large animal models that allow the study of the impact of age on CKD and HFpEF in a translational fashion. This manuscript reports the first large preclinical model of CKD-HFpEF and metabolic derangements in naturally aged swine.

METHODS

CKD-HFpEF was induced in naturally aged (6-9 years old) and young (3 months old) pigs, followed for 14 weeks, and compared to normal young and old controls (n = 5/group). Renal and cardiac hemodynamics were quantified in vivo by multidetector-CT, echocardiography, and pressure-volume relationship studies. Renal and cardiac microvascular (MV) architecture (3D-micro-CT) and morphometric analysis (staining) were investigated ex vivo.

RESULTS

Both young and old pigs developed CKD-HFpEF, but the renal, cardiac, and metabolic phenotype was accentuated in aging animals. Aging and CKD-HFpEF influenced fasting insulin levels and insulin resistance, glomerular filtration rate, cortical MV density, glomerulosclerosis, perivascular fibrosis, and tubular injury. Tubule-interstitial fibrosis and peritubular capillary density were influenced by aging, CKD-HFpEF, and their interaction (2-way ANOVA). Similarly, cardiac MV density, perivascular fibrosis, and myocardial remodeling were influenced by aging and CKD-HFpEF, and E/A by their interaction. Notably, renal and cardiac MV density correlated with renal and cardiac functional and structural changes.

CONCLUSION

Our study establishes the first large animal model of aging CKD-HFpEF, allowing the investigation of age as a biological variable in cardiorenal and metabolic diseases. This new platform could foster new age-related research toward developing therapeutic interventions in CKD-HFpEF.

An epidemiological study on the factors including genetic polymorphism influencing ALT >30 U/L and liver fibrosis progression in metabolic dysfunction-associated steatotic liver disease among the general population

Background and Aim

Identifying the factors contributing to the progression of metabolic dysfunction-associated steatotic liver disease (MASLD), a lifestyle-related disease, is crucial for preventing future liver-related deaths. This study aimed to epidemiologically investigate factors, including single-nucleotide polymorphisms (SNPs) associated with alanine aminotransferase (ALT) levels >30 U/L and potential risk factors for liver fibrosis, in a general population cohort of patients with MASLD.

Methods

Among 1059 participants in the health checkup project, 228 who were diagnosed with MASLD were analyzed. Liver fat content and stiffness were measured using FibroScan, and 13 SNPs associated with non-alcoholic fatty liver disease (NAFLD) were measured in addition to other clinical parameters.

Results

In the multivariate analysis, male sex, younger age, and high triglyceride levels were significant risk factors for ALT levels >30 U/L (P-value < 0.05). Furthermore, among the 13 SNPs measured, only the GG genotypes of patatin-like phospholipase domain-containing 3 gene (PNPLA3) rs738409 and rs2896019 were significant risk factors for ALT levels >30 U/L (P-value 0.004 and 0.007). The GG genotypes of PNPLA3 rs738409 and rs2896019 had higher FibroScan-aspartate aminotransferase (FAST) and APRI scores than the CC + CG and TT + TG genotypes (P-value < 0.05). In addition, multivariate analysis revealed that the GG genotypes of rs738409 and rs2896019 were significant risk factors independent of cardiovascular metabolic risk for patients with MASLD (P-value 0.038 and 0.021).

Conclusion

An individualized treatment approach is warranted for patients with MASLD due to the influence of various factors on its progression, including genetic factors and lifestyle diseases.

Metabolic dysfunction-associated steatotic liver disease: The question of long-term high-normal alanine aminotransferase as a screening test

The growing prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is being driven by the obesity epidemic. The quest for solutions continues particularly with regard to early detection. This editorial comments on the utility of long-term high-normal alanine aminotransferase (ALT) in screening for MASLD. Chen et al found that new onset MASLD can be detected by repetitively high normal ALT. Implicit in this concept is the question of what should be the accepted upper limit of normal (ULN) for ALT. It was previously set at 40 IU/L based on studies that included people with subclinical liver disease but the new consensus is 30/19 U/L in healthy males/females. Thus, when Chen et al defines the ULN as 40 U/L, others may view it as excessively high. It is important to recognize the variables affecting ULN e.g. instrumentation, diurnal variations, exercise and ageing. These variables matter when the distinctions are subtle e.g. normal vs high-normal. In this regard, the utility of long-term high normal ALT as a disease marker could be enhanced by combining it with other biomarkers, imaging and MASLD genetics to create machine learning classifiers. All in all, Chen et al's work on long-term high normal ALT as a marker of new-onset MASLD deserves merit.

Serum Transaminases and Older Adults: Distribution and Associations With All-Cause Mortality

BACKGROUND

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are commonly ordered tests in general medical practice. However, their distribution and significance in older adults are understudied. As such, we aimed to evaluate sex-stratified distribution of both ALT and AST in older adults (≥70 years) and assess for associations with mortality.

METHODS

Post-hoc analysis of the ASPirin in Reducing Events in the Elderly (ASPREE) randomized, placebo-controlled trial of daily low-dose aspirin for initially relatively healthy older persons. Univariate analysis and multiple logistic regression were used to explore baseline characteristics. Cox regression and restricted cubic splines were used to examine links between transaminase levels and mortality.

RESULTS

Of the 11 853 participants with ALT and AST levels, 1 054 (8.9%) deaths were recorded over a median of 6.4 (interquartile range [IQR] 5.4-7.6) years. For ALT, the lowest quintiles for males and females were 6-15 and 5-13 U/L, respectively; for AST, the lowest quintiles were 8-18 and 7-17 U/L, respectively. On both univariate and models adjusted for covariates including age, body mass index, frailty, diabetes, and kidney disease, males and females in the lowest quintile of ALT had an increased hazard of mortality (aHR 1.51 [95% confidence interval {CI} 1.14-1.99] and aHR 1.39 [95% CI 1.03-1.88], respectively). For the lowest quintile of AST, only males were at increased risk (aHR 1.33 [95% CI 1.04-1.70]). Associations remained significant when removing outliers.

CONCLUSIONS

Low ALT levels independently confer an increased hazard of mortality for older males and females; low AST only affected older male survival. Further evaluation of mechanisms would be worthwhile, and re-evaluating the lower limit of normal for ALT in older adults should be considered.

Aspartate aminotransferase to alanine aminotransferase ratio and short-term prognosis of patients with type 2 diabetes hospitalized for heart failure

INTRODUCTION

We aimed to explore the prognostic value of the aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio in non-surgical patients with type 2 diabetes hospitalized for heart failure.

MATERIAL AND METHODS

Using a large electronic medical record-based cohort of diabetes in China (WECODe), we gathered data on non-surgical hospitalized patients with type 2 diabetes and heart failure from 2011 to 2019. Baseline AST/ALT ratio was calculated. The primary outcomes were all-cause death within 30 days after discharge, composite cardiac events, major acute kidney injury, and major systemic infection. A multivariable Cox proportional regression model was utilized to evaluate the association between the AST/ALT ratio and outcomes.

RESULTS

This retrospective cohort included 8,073 patients (39.4% women) with type 2 diabetes hospitalized for heart failure. The median age was 71 years. Higher AST/ALT ratio was associated with higher risks of poor endpoints (with per standard deviation increment in AST/ALT ratio, for death within 30 days after discharge: adjusted hazard ratio [HR] = 1.35, 95% confidence interval [CI], 1.21 to 1.50; for composite cardiac events: HR = 1.18, 95% CI: 1.06 to 1.31). Compared to patients in the lowest quartile for the AST/ALT ratio, those in the highest quartile have elevated risk of death within 30 days after discharge and major systemic infection (HRs [95% CIs] 1.61 [1.18 to 2.19] and 1.28 [1.06 to 1.56], respectively). Subgroup analyses and sensitivity analyses confirmed the robustness of the findings.

CONCLUSIONS

Type 2 diabetes patients hospitalized for heart failure with the AST/ALT ratio in the highest quartile face a poor short-term prognosis.

A Framework for an Effective Healthy Longevity Clinic

In the context of an aging global population and the imperative for innovative healthcare solutions, the concept of longevity clinics emerges as a timely and vital area of exploration. Unlike traditional medical facilities, longevity clinics offer a unique approach to preclinical prevention, focusing on "prevention of prevention" through the utilization of aging clocks and biomarkers from healthy individuals. This article presents a comprehensive overview of longevity clinics, encompassing descriptions of existing models, the development of a proposed framework, and insights into biomarkers, wearable devices, and therapeutic interventions. Additionally, economic justifications for investing in longevity clinics are examined, highlighting the significant growth potential of the global biotechnology market and its alignment with the goals of achieving active longevity. Anchored by an Analytical Center, the proposed framework underscores the importance of data-driven decision-making and innovation in promoting prolonged and enhanced human life. At present, there is no universally accepted standard model for longevity clinics. This absence highlights the need for additional research and ongoing improvements in this field. Through a synthesis of scientific research and practical considerations, this article aims to stimulate further discussion and innovation in the field of longevity clinics, ultimately contributing to the advancement of healthcare practices aimed at extending and enhancing human life.

Alanine aminotransferase as a risk marker for new-onset metabolic dysfunction-associated fatty liver disease

In this editorial, we comment on the article by Chen et al. Metabolic dysfunction-associated fatty liver disease (MAFLD) is a global public health burden whose incidence has risen concurrently with overweight and obesity. Given its detrimental health impact, early identification of at-risk individuals is crucial. MAFLD diagnosis is based on evidence of hepatic steatosis indicated by liver biopsy, imaging, or blood biomarkers, and one of the following conditions: Overweight/ obesity, type 2 diabetes mellitus, or metabolic dysregulation. However, in large-scale epidemiological studies, liver biopsies are not feasible. The application of techniques such as ultrasonography, computed tomography, magnetic resonance imaging, and magnetic resonance spectroscopy is restricted by their limited sensitivity, low effectiveness, high costs, and need for specialized software. Blood biomarkers offer several advantages, particularly in large-scale epidemiological studies or clinical scenarios where traditional imaging techniques are impractical. Analysis of cumulative effects of excess high-normal blood alanine aminotransferase (ALT) levels of blood ALT levels could facilitate identification of at-risk patients who might not be detected through conventional imaging methods. Accordingly, investigating the utility of blood biomarkers in MAFLD should enhance early detection and monitoring, enabling timely intervention and management and improving patient outcomes.

Higher serum alanine aminotransferase levels and the incidence of hypertension: The Kailuan cohort study

Objective

The association between serum alanine aminotransferase (ALT) concentrations and the incidence of hypertension remains unclear. To explore the association between serum ALT levels and the risk of incident hypertension based on the Kailuan cohort study.

Methods

People who had participated in health check-ups in 2006-2007 without hypertension, cardiovascular, or liver diseases were enrolled and received follow-ups every two years until December 2017. Hypertension was defined as systolic blood pressure/diastolic blood pressure ≥140/90 mmHg or using anti-hypertensive medication. A multivariable-adjusted Cox regression model was used to estimate the hazard ratio (HR) and its corresponding 95 % confidence intervals (95 % CIs).

Results

During 10.5 years of follow-up, 24,023 (50.7 %) participants were diagnosed with hypertension. The HR of incident hypertension was 1.02 (95 % CI=1.01-1.03) for each 10 U/L increment of ALT concentrations. Participants with elevated ALT levels (>40 U/L) had an increased incidence of hypertension by 7 % (HR =1.07; 95 % CI=1.01-1.13). Besides, the HR was 1.10 (95 % CI=1.06-1.15), 1.13 (95 % CI=1.08-1.18), and 1.22 (95 % CI=1.16-1.30) (P for trend <0.001) in (10-20], (20-30], and (30-40] groups, compared with ≤10 U/L group. In addition, participants whose ALT levels decreased to the normal range at the first follow-up had a 23 % lower incidence of hypertension than those with elevated ALT levels at baseline and the first follow-up.

Conclusion

People with higher serum ALT levels may have an increased risk of incident hypertension and thus may benefit from heightened surveillance for hypertension and lifestyle interventions to reduce the risk of hypertension.

Metabolic dysfunction-associated steatotic liver disease in older adults is associated with frailty and social disadvantage

BACKGROUND & AIMS

The burden of metabolic dysfunction-associated steatotic liver disease (MASLD) is growing rapidly, as is the number of older adults globally. However, relatively few studies have been performed evaluating the prevalence and risk factors for MASLD in older adults. As such, we aimed to identify the prevalence of MASLD in older adults, as well as sociodemographic, clinical, functional and biochemical associations.

METHODS

The study population included older adults without a history of cardiovascular disease, dementia or independence-limiting functional impairment who had participated in the ASPirin in Reducing Events in the Elderly (ASPREE) randomised trial. MASLD was defined using the Fatty Liver Index (FLI). Associations were identified using Poisson regression with robust variance for FLI ≥ 60 vs FLI < 30.

RESULTS

9097 Australian participants aged ≥70 years had complete biochemical and anthropometric data to identify MASLD. The study population had a mean age of 75.1 ± 4.3 years and was 45.0% male. Almost one-third (33.0%) had prevalent MASLD, and the prevalence decreased with increasing age (adjusted RR [aRR] 0.96, 95% CI: 0.96-0.97). MASLD was also negatively associated with social advantage (aRR 0.94, 95% CI: 0.90-0.99) and exercise tolerance and was positively associated with diabetes mellitus (aRR: 1.22, 95% CI: 1.16-1.29), hypertension (aRR: 1.31, 95% CI: 1.22-1.41), male sex (aRR: 1.66, 95% CI: 1.57-1.74), pre-frailty (aRR: 1.99, 95% CI: 1.82-2.12) and frailty (aRR: 2.36, 95% CI: 2.16-2.56). MASLD and nonalcoholic fatty liver disease (NAFLD) results were 100% concordant.

CONCLUSION

This study in a large cohort of relatively healthy community-dwelling older adults shows that MASLD is common, decreases with age and is associated with poorer metabolic health, social disadvantage and frailty.

Diagnostic significance of alanine aminotransferase isoenzymes in alcoholic and non-alcoholic fatty liver cancers

OBJECTIVES

Alanine aminotransferase (ALT) expression is highly elevated in the serum of patients with hepatocellular carcinoma. However, the role of ALT isoenzymes in the total ALT activity remains unclear. In the present study, we systematically investigated the role of ALT isoenzymes in alcoholic and non-alcoholic fatty liver cancer.

MATERIALS AND METHODS

The expression of ALT1 and ALT2 at the mRNA and protein levels in 25 paired primary liver cancer tissues was detected by reverse transcription quantitative PCR (RT-qPCR), Western blotting, and immunohistochemistry. Serum ALT activity was determined using an automated biochemical analyzer.

RESULTS

The mRNA and protein expression levels of ALT1 and ALT2 were lower in the tissues of alcoholic and non-alcoholic fatty liver cancers than in the paracancerous tissues. Notably, ALT2 was highly expressed in non-alcoholic fatty liver cancer tissues compared with alcoholic fatty liver cancer tissues. Total serum ALT activity was mainly contributed by ALT1 in alcoholic fatty liver cancer, whereas ALT1 contributed only marginally more to the total ALT activity than ALT2 in non-alcoholic fatty liver cancer. ALT2/ALT1 ratio can well discriminate normal control group, alcoholic liver cancer and non-alcoholic liver cancer.

CONCLUSION

ALT1 contributed more to the total ALT activity than ALT2 in both alcoholic and non-alcoholic fatty liver cancer. Serum ALT2 to ALT activity was higher in non-alcoholic fatty liver cancer than that in alcoholic fatty liver cancer. ALT2/ALT1 ratio has some diagnostic significance for alcoholic and non-alcoholic liver cancer.

Alanine aminotransferase to high- density lipoprotein cholesterol ratio is positively correlated with the occurrence of diabetes in the Chinese population: a population-based cohort study

Objective

Both alanine aminotransferase (ALT) and high-density lipoprotein cholesterol (HDL-C) are closely related to glucose homeostasis in the body, and the main objective of this study was to investigate the association between ALT to HDL-C ratio (ALT/HDL-C ratio) and the risk of diabetes in a Chinese population.

Methods

The current study included 116,251 participants who underwent a healthy physical examination, and the study endpoint was defined as a diagnosis of new-onset diabetes. Multivariate Cox regression models and receiver operator characteristic curves were used to assess the association of the ALT/HDL-C ratio with diabetes onset.

Results

During the average observation period of 3.10 years, a total of 2,674 (2.3%) participants were diagnosed with new-onset diabetes, including 1,883 (1.62%) males and 791 (0.68%) females. After fully adjusting for confounding factors, we found a significant positive association between the ALT/HDL-C ratio and the risk of diabetes [Hazard ratios 1.06, 95% confidence intervals: 1.05, 1.06], and this association was significantly higher in males, obese individuals [body mass index ≥ 28 kg/m2] and individuals aged < 60 years (All P interaction < 0.05). In addition, the ALT/HDL-C ratio was significantly better than its components ALT and HDL-C in predicting diabetes in the Chinese population.

Conclusion

There was a positive relationship between ALT/HDL-C ratio and diabetes risk in the Chinese population, and this relationship was significantly stronger in males, obese individuals, and individuals younger than 60 years old.

The newly proposed alanine aminotransferase to high-density lipoprotein cholesterol ratio has shown effectiveness in identifying non-alcoholic fatty liver disease

Objective

Alanine aminotransferase (ALT) and high-density lipoprotein cholesterol (HDL-C) are important predictive factors for non-alcoholic fatty liver disease (NAFLD). The aim of this study was to analyze the association between the ALT/HDL-C ratio and NAFLD.

Methods

We conducted a retrospective analysis of data from 14,251 individuals participating in the NAGALA project's health screening program. The presence of NAFLD was diagnosed based on the participants' alcohol consumption status and liver ultrasonography images. Multivariable logistic regression models were used to assess the association between the ALT/HDL-C ratio and NAFLD. Receiver operating characteristic (ROC) analysis was performed to determine and compare the effectiveness of ALT, HDL-C, the aspartate aminotransferase to HDL-C (AST/HDL-C) ratio, the gamma-glutamyl transferase to HDL-C (GGT/HDL-C) ratio and the ALT/HDL-C ratio in identifying NAFLD.

Results

We observed a significant positive association between the ALT/HDL-C ratio and the prevalence of NAFLD. For each standard deviation (SD) increase in the ALT/HDL-C ratio, the adjusted odds ratio (OR) for NAFLD among the participants was 3.05 [95% confidence interval (CI): 2.63, 3.53], with the highest quartile of ALT/HDL-C ratio having a 9.96-fold increased risk compared to the lowest quartile. In further subgroup analyses stratified by gender, age, and waist circumference (WC), we observed a significantly higher risk of NAFLD associated with the ALT/HDL-C ratio among individuals aged ≥45 years, males, and those who were abdominal obesity. Furthermore, based on the results of ROC analysis, we found that the ALT/HDL-C ratio [area under the curves (AUC): 0.8553] was significantly superior to ALT, HDL-C, AST/HDL-C ratio and GGT/HDL-C ratio in identifying NAFLD (All Delong P<0.05); the threshold of suggested ALT/HDL-C ratio for identifying NAFLD was 15.97.

Conclusion

This population-based study demonstrates a positive association between the ALT/HDL-C ratio and NAFLD. The ALT/HDL-C ratio can effectively identify individuals with NAFLD.

Analysis of time-dependent changes in the FIB4 index in patients with obesity receiving weight reduction therapy

Weight reduction therapy represents a fundamental strategy to prevent nonalcoholic fatty liver disease (NAFLD) in patients with obesity, which may result in liver fibrosis. Histological findings previously demonstrated that weight reduction therapy attenuated NAFLD. The FIB4 index is widely used to assess the status of NAFLD. The present study investigated whether the FIB4 index improved during weight reduction therapy. We used cohort data of the Japan Obesity and Metabolic syndrome Study and examined the correlation between body weight (BW) loss (BW loss) and changes in the FIB4 index (ΔFIB4 index) in patients who successfully reduced their BW by more than 5% from baseline BW after 3, 6, and 12 months (M) of weight reduction therapy. A negative correlation (r = −0.342, p = 0.029) was observed between BW loss and FIB4 index after 3 M, but not after 6 M, whereas a positive correlation (r = 0.298, p = 0.03) was noted after 12 M. These results revealed changes in the correlation between ΔBW loss and ΔFIB4 index during the therapy, mainly due to time-dependent changes in components of the FIB4 index formula. Thus, we concluded that the FIB4 index is useful and reliable to assess liver fibrosis until 3 M during weight reduction therapy. However, after 3 M, we should recognize that the FIB4 index may not reflect liver status. Therefore, it is important to consider this characteristic of the FIB4 index as a limitation when assessing liver fibrosis in obese patients receiving weight reduction therapy.

Establishment of gender- and age-specific reference intervals for serum liver function tests among the elderly population in northeast China: a retrospective study

INTRODUCTION

Reference intervals (RIs) for younger population may not apply to the elderly population. The aim of this study was to establish gender- and age-specific RIs for serum liver function tests among the elderly population and to compare with younger population RIs currently used in China and other countries.

MATERIALS AND METHODS

This was a retrospective study, and subjects (≥ 18 year-old) were recruited from the laboratory information system (LIS) at the First Hospital of Jilin University between April 2020 and April 2021. The following parameters were collected: aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), total bilirubin (TBIL), and direct bilirubin (DBIL). The Tukey method was used to eliminate outliers. Reference intervals were established by the nonparametric method.

RESULTS

A total of 23,597 healthy individuals were enrolled in the study. From all parameters AST, ALT, TP and ALB required no gender partition, while ALT, GGT, TP, ALB and DBIL required different partitions for age. Activities and concentrations of ALT, ALB, and TP showed a downward trend in the elderly aged 60-89. In contrast, DBIL showed a gradual upward trend.

CONCLUSION

The RIs for liver function tests among healthy elderly population were different from those among young population in China. There were apparent gender and age differences in the RIs of liver function for elderly and significant differences compared with national standards and RIs in other countries. Therefore, it is necessary to establish gender- and age-specific RIs for serum liver function tests among the elderly population.

Gender Difference in Liver Enzymes in Newly Defined Subgroups of Diabetes Revealed by a Data-Driven Cluster Analysis

BACKGROUND

Recently, a newly proposed data-driven approach for classifying diabetes has challenged the status quo of the classification of adult-onset patients with diabetes. This study investigated the association between liver injury and diabetes, classified by data-driven cluster analysis, as liver injury is a significant risk factor for diabetes.

METHODS

We enrolled 822 adult patients with newly diagnosed diabetes. Two-step cluster analysis was performed using six parameters, including age at diagnosis, body mass index, hemoglobin A1C, homoeostatic assessment model 2 estimates about insulin resistance (HOAM2-IR) and beta-cell function (HOMA2-B), and glutamic acid decarboxylase antibodies (GADA) positivity. Patients were allocated into five clusters. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity were compared as indicators of liver injury among clusters.

RESULTS

Serum ALT and AST activities were significantly different among clusters (P=0.002), even among those without GADA positivity (P=0.004). Patients with severe insulin-resistant diabetes (SIRD) and mild obesity-related diabetes (MOD) had a more severe liver injury. Gender dimorphism was also found for serum ALT and AST activities among subgroups. Female patients had better liver function than males with SIRD and MOD.

CONCLUSIONS

We verified the feasibility of a newly proposed diabetes classification system and found robust and significant relationship and gender differences between serum ALT and AST activities and diabetes in some specific subgroups. Our findings indicate that more attention should be paid to diabetes subgroups when studying risk factors, indicators, or treatment in diabetic research.

Trends in indirect liver function marker testing in Wales from 2000 to 2017 and their association with age and sex: an observational study

Objective

If non-invasive markers of liver fibrosis were recorded frequently enough in clinical practice, it might be feasible to use them for opportunistic community screening for liver disease. We aimed to determine their current pattern of usage in the national primary care population in Wales.

Design

Using the Secure Anonymised Information Linkage (SAIL) Databank at Swansea University (2000–2017), we quantified the frequency of common liver blood tests (aspartate aminotransferase (AST), alanine aminotransferase (ALT), platelet count and albumin) used in fibrosis marker algorithms. We examined measurement variation by age and sex.

Results

During the 18-year study period, there were 2 145 178 adult patients with at least one blood test available for analysis. Over the study period, the percentage of SAIL patients receiving an ALT test in each year increased from 2% to 33%, with platelet count and albumin measurement increasing by a similar factor. AST testing, although initially rising, had decreased to 1% by the end of the study. AST and ALT values varied by age and sex, particularly in males with the upper normal range of ALT values decreasing rapidly from 90 U/L at age 30 to 45 U/L by age 80.

Conclusion

The reduction in AST testing to only 1% of the adult population limits the use of many non-invasive liver marker algorithms. To enable widespread screening, alternative algorithms for liver fibrosis that do not depend on AST should be developed. Liver fibrosis markers should be modified to include age-specific and sex-specific normal ranges.

Protective Effects of A. sativa against Oxidative Stress-Induced Liver Damage in Ovariectomized Mice

Postmenopausal women express great failure in their ovarian hormone production, especially estrogen. This deficiency may promote hypercholesterolemia and accelerate the redox imbalance. The present study was designed to evaluate the protective effect of Avena sativa against estrogen deficiency-induced liver and uterus oxidative injury in experimental ovariectomized mice. Female mice were randomly divided into five groups: group one (negative control) received normal diet and distilled water (C), group two (positive control) received daily enriched diet with oat grains and was kept on tap distilled water at a dose of 200 mg kg⁻¹ d⁻¹ (A), group three (ovariectomized mice) was nontreated fed with normal diet (O), group four includes ovariectomized mice treated daily with estradiol given by intraperitoneal injection at a dose of 100 μg kg⁻¹ d⁻¹ (OE), and the fifth group also includes ovariectomized mice which received enriched diet with oat grain parts with the same dose given to group two. The treatment period lasted two consecutive months. Both oat and hormonal treatments of ovariectomized groups resulted in a significant reduction in triglycerides and total cholesterol and increased high-density lipoprotein (HDL) levels in the plasma after 21 and 60 days of treatment. Besides, the coadministration of A. sativa has decreased the activities of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) and increased transaminase activities after 21 and 60 days of treatment. On the other hand, this cereal has restored the enzymatic (SOD, CAT, and GPx) and nonenzymatic antioxidant activities (GSH) as well as the elevated thiobarbituric acid reactive substances (AOPP and PCO) to near-normal values. The beneficial effects of this cereal were confirmed by a histological study of the liver and uterus of all previous cited groups. Our finding emphasized the antioxidant and antilipidemic effect of oat grain part, suggesting the use of this cereal in the prevention of liver and uterus diseases that occurred in postmenopausal women.

Blood-based biomarkers and long-term risk of frailty - experience from the Swedish AMORIS cohort

BACKGROUND

Frailty is associated with reduced quality of life, poor health outcomes, and death. Past studies have investigated how specific biomarkers are associated with frailty but understanding biomarkers in concert with each other and the associated risk of frailty is critical for clinical application.

METHODS

Using a sample aged ≥59 years at baseline from the Swedish AMORIS cohort (n=19341), with biomarkers measured at baseline (1985-1996), we conducted latent class analysis with 18 biomarkers and used Cox models to determine the association between class and frailty and all-cause mortality.

RESULTS

Four classes were identified. Compared to the largest class, the Reference class (81.7%), all other classes were associated with increased risk of both frailty and mortality. The Anemia class (5.8%), characterized by comparatively lower iron markers and higher inflammatory markers, had HR=1.54, 95% CI 1.38, 1.73 for frailty and HR=1.76, 95% CI 1.65, 1.87 for mortality. The Diabetes class (6.5%) was characterized by higher glucose and fructosamine, and had HR=1.59, 95% CI 1.43, 1.77 for frailty and HR=1.74, 95% CI 1.64, 1.85 for mortality. Finally, the Liver class (6.0%), characterized by higher liver enzyme levels, had HR=1.15, 95% CI 1.01, 1.30 for frailty and HR=1.40, 95% CI 1.31, 1.50 for mortality. Sex-stratified analyses did not show any substantial differences between men and women.

CONCLUSIONS

Distinct sets of commonly available biomarkers were associated with development of frailty and monitoring these biomarkers in patients may allow for earlier detection and possible prevention of frailty, with the potential for improved quality of life.

Significantly Reduced Alanine Aminotransferase Level Increases All-Cause Mortality Rate in the Elderly after Ischemic Stroke

(1) Background: A significantly reduced alanine aminotransferase (ALT) level is being recognized as a risk factor of increasing mortality in the elderly in relation to frailty. In the elderly, both frailty and ischemic stroke are not only common, but are also associated with mortality. The aim of this research was to investigate whether a significantly reduced ALT level increases the all-cause mortality rate in the elderly with ischemic stroke. (2) Methods: Between February 2014 and April 2019, a retrospective study of 901 patients with ischemic stroke admitted to a university-affiliated hospital was conducted. Cox proportional hazard regression was used to determine whether a significantly reduced ALT level is an independent risk factor for mortality in elderly patients after an ischemic stroke. (3) Results: This study enrolled 323 older adults (age ≥ 65 years) who were first diagnosed with ischemic stroke. The mean age of the participants was 76.5 ± 6.6 years, the mean survival time was 37.1 ± 20.4 months, and the number of deaths was 96 (29.7%). Our results showed that reduced ALT level (less than 10 U/L) increased the risk of all-cause mortality in the elderly after ischemic stroke (adjusted HR: 3.24, 95% CI: 1.95–5.41; p < 0.001). (4) Conclusions: A significantly reduced ALT level at the time of diagnosis (less than 10 U/L) is an independent risk factor that increases the mortality rate in the elderly after ischemic stroke.

Association between High-Sensitive C-Reactive Protein and the Development of Liver Damage in Japanese Male Workers

BACKGROUND

The aim of this study was to determine whether a causative relationship exists between the development of liver damage and increased high-sensitivity C-reactive protein (HsCRP) levels by long-term follow-up in Japanese workers.

METHODS

The target participants comprised 7830 male workers in a Japanese steel company. The prospective cohort study was performed over a 6-year period, and annual health screening information was analyzed by pooled logistic regression. The endpoint, regarded as the development of liver damage, was defined as aspartate aminotransferase (AST) ≥ 40 IU/L.

RESULTS

A significant relationship between the development of liver damage and increased HsCRP levels was observed after adjusting for confounding factors such as various physiological and blood chemistry parameters and lifestyle factors. The odds ratio of a 1.5-fold increase in HsCRP was 1.07 (95% confidence interval: 1.03-1.10, p < 0.001).

CONCLUSIONS

The results suggested that an increase of HsCRP is associated with the development of liver damage.

Serum alanine aminotransferase activity and risk factors for cardiovascular disease in a Caucasian population: the Tromsø study

Background

High and low levels of serum alanine aminotransferase (ALT) are both associated with cardiovascular diseases (CVD) risks especially in elderly, but the mechanisms are less known. This study investigated associations between ALT and CVD risk factors including effects of sex and age in a Caucasian population.

Methods

Cross-sectional data were analysed sex-stratified in 2555 men (mean age 60.4 years) and 2858 women (mean age 60.0 years) from the population study Tromsø 6. Associations were assessed by variance analysis and multivariable logistic regression of odds to have abnormal ALT. Risk factors included body mass index (BMI), waist-to-hip-ratio, blood pressure, lipids, glucose, glycated haemoglobin and high-sensitive C-reactive protein (CRP).

Results

Abnormal elevated ALT was detected in 113 men (4.4%) and 188 women (6.6%). Most CVD risk factors associated positively with ALT in both sexes except systolic blood pressure and CRP (women only), while ALT was positively associated with age in men when adjusted for CVD risk factors, P < 0.001. BMI predicted ALT in men (OR 0.94; 95% CI 0.88–1.00, P = 0.047) and women (OR 0.90; 95% CI 0.86–0.95, P < 0.001). A linear inversed association between age and ALT in men and a non-linear inversed U-trend in women with maximum level between 60 and 64 years were found.

Conclusion

This study confirms a positive relationship between ALT and CVD risk factors, particularly BMI. Age is not a major confounder in the ALT-CVD relationship, but separate sex-analyses is recommended in such studies.

Factors associated with elevated alanine aminotransferase in employees of a German chemical company: results of a large cross-sectional study

BACKGROUND

We aimed to determine the prevalence of elevated alanine aminotransferase (eALT) in employees of a German chemical company, and analyze its association with sociodemographic, work- and lifestyle-related factors.

METHODS

The cross-sectional study is based on data surveyed from occupational health check-ups between 2013 and 2018 at the site clinic of a chemical company based in Ludwigshafen, Germany. We used logistic regression analyses to assess the association between sociodemographic, work- and lifestyle-related characteristics and eALT. Quantile regression technique was applied to investigate if associations vary across different quantiles of the ALT distribution.

RESULTS

Participants (n = 15,348) were predominantly male (78.3%) with a mean age of 42.2 years (SD 10.7). The prevalence of eALT was 18.5% (21.6% in men/7.2% in women) with a geometric mean of 28.9 U/L (32.8 U/L in men/18.5 U/L in women). In the multivariable logistic regression model, odds of eALT were significantly higher for males (OR 2.61; 95%-CI 2.24-3.05), manual workers (OR 1.23; 95%-CI 1.06-1.43), overweight (OR 2.66; 95%-CI 2.36-3.00) or obese respondents (e.g. OR 7.88; 95%-CI 5.75-10.80 for obesity class III), employees who consume any number of alcoholic drinks/week (e.g. OR 1.32; 95%-CI 1.16-1.49 for ≥ 3 drinks per week) and diabetics (OR 1.47; 95%-CI 1.22-1.78). Additionally, season of participation was significantly associated with eALT, with odds being higher for participation in spring, fall or winter, as compared to summer. A significant interaction between age and gender (pInteraction < 0.001) was found, showing approximately a u-shaped age/ALT relationship in women and an inversely u-shaped relationship in men. Quantile regression showed an increasing positive effect of male gender, overweight/obesity, and for diabetics on ALT level when moving from the lowest (q0.1) to the highest (q0.9) considered quantile. Additionally, from the lowest to the highest quantile an increasing negative effect on ALT for older age was observed.

CONCLUSIONS

Prevalence of eALT in our sample of employees can be considered as high, with almost one in five participants affected. Identification of risk groups allows the implementation of targeted preventive measures in order to avoid transition to severe morbidity.

Eating quickly is associated with a low aspartate aminotransferase to alanine aminotransferase ratio in middle-aged adults: a large-scale cross-sectional survey in Japan

BACKGROUND

An elevated alanine aminotransferase (ALT) and a low aspartate aminotransferase (AST) to ALT ratio (AST/ALT ratio) suggest nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, increasing the risk of liver cirrhosis and hepatocellular carcinoma. In addition, eating quickly has been found to be associated with outcomes such as obesity. This study sought to investigate the relationship between eating quickly and an elevated ALT or a low AST/ALT ratio in Japanese middle-aged adults.

METHODS

The present study included 283,073 adults aged 40-64 years who had annual health checkups in Japan from April 2013 to March 2014. The data of serum parameters and lifestyle factors, including eating speed, were analyzed. An elevated ALT was defined as > 40 U/L, and a low AST/ALT ratio was defined as < 1. Logistic regression analysis was performed to calculate the odds ratios (ORs) and the 95% confidence intervals (CIs) for an elevated ALT and a low AST/ALT ratio.

RESULTS

Significantly increased ORs for an elevated ALT were observed in men (OR: 1.45, 95% CI: 1.41-1.49) and women (OR: 1.34, 95% CI: 1.25-1.43). Moreover, eating quickly significantly increased the ORs for a low AST/ALT ratio in men (OR: 1.53, 95% CI: 1.50-1.56) and women (OR: 1.36, 95% CI: 1.31-1.41). When the analysis was limited to those with ALT ≤40 U/L, eating quickly had significantly increased ORs for a low AST/ ALT ratio, regardless of sex.

CONCLUSIONS

Eating quickly was significantly associated with an elevated ALT and a low AST/ALT ratio. In addition, eating quickly was significantly associated with a low AST/ALT ratio even for those without ALT elevation. This study suggested that modification of eating speed may contribute to reducing the risk for an elevated ALT and a low AST/ALT ratio.

Prevalence of Elevated Alanine Aminotransferase by Diagnostic Criterion, Age, and Gender among Adolescents

Background

Serum alanine aminotransferase (ALT) activity was measured not only to detect liver disease, but also to monitor overall health. The purpose of this study was to obtain the prevalence of elevated ALT levels among adolescents.

Methods

In a school-based cross-sectional study, a representative sample was analyzed from 9 middle and high schools in Shenzhen, China, during 2017 to 2018. Elevated ALT was defined as diagnostic criterion I (>30 U/L for boys and >19 U/L for girls) and diagnostic criterion II (>40 U/L).

Results

From the adolescent population, a total of 7281 students (boys, 4014, and girls, 3267) aged from 10 to 17 years were collected. The prevalence of elevated ALT was 7.11% (6.88% for boys and 7.41% for girls) by criterion I and 2.72% (3.96% for boys and 1.19% for girls) by criterion II. Based on the Shenzhen census and Chinese national census population, the adjusted prevalence of elevated ALT was 7.65% (boys 7.19% and girls 8.21%) and 6.79% (boys 6.07% and girls 7.56%) by criterion I and 2.85% (boys 4.20% and girls 1.16%) and 2.43% (boys 3.49% and girls 1.29%) by criterion II. For age, the overall trends were increasing progressively, regardless of the use of diagnostic criteria for an elevated ALT activity.

Conclusions

This study supplements the gap that the prevalence of elevated ALT levels differed in gender, age, and criteria among adolescents of Shenzhen. We should take the prevalence as a predictor and continue to play a warning and preventive role in preparation for further intervention.

Associations of serum liver enzyme levels and their changes over time with all-cause and cause-specific mortality in the general population: a large-scale national health screening cohort study

OBJECTIVES

To investigate the associations of the levels of liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyltransferase (GGT), at baseline and their changes over time with mortality.

DESIGN

Cohort study.

SETTING, PARTICIPANTS AND OUTCOME MEASURES

We analysed the data of 484 472 individuals from the National Health Insurance Service-National Health Screening Cohort (2002-2013). We used two exposure indices: (1) deciles of baseline ALT, AST and GGT levels measured in 2002 or 2003 and (2) deciles of changes in ALT, AST and GGT levels over a 4 year period (2002-2006 or 2003-2007). We constructed Cox models to evaluate the associations of these exposure indices with mortality (2008-2013).

RESULTS

We found non-monotonic dose-response associations between the baseline levels of ALT and AST and all-cause mortality. We also found a monotonic non-linear association between the baseline levels of GGT and all-cause mortality (10th decile: HR=2.05, 95% CI: 1.93 to 2.18). Compared with the ninth, sixth and fourth deciles of changes in ALT (8-13 U/L), AST (1 U/L) and GGT (-3 to -2 U/L) over time, respectively, the risks of all-cause mortality increased in both the higher and lower deciles of changes in the corresponding liver enzyme levels (10th decile: HR=1.36, 95% CI 1.24 to 1.48; 1st decile: HR=1.46, 95% CI 1.34 to 1.59 for ALT; 10th decile: 1.55, 95% CI 1.40 to 1.71; 1st decile: HR=1.53, 95% CI 1.38 to 1.69 for AST; 10th decile: HR=1.71, 95% CI 1.56 to 1.88; 1st decile: HR=1.67, 95% CI 1.52 to 1.84 for GGT). These non-monotonic dose-response associations remained when analyses were stratified by the medians or quartiles of the baseline liver enzyme levels.

CONCLUSIONS

The levels of liver enzymes at baseline and over time showed non-linear associations with mortality.

Circulating ALT Levels in Healthy Volunteers Over Life-Span: Assessing Aging Paradox and Nutritional Implications

Background: Two facts are generally recognized: (1) development of nonalcoholic fatty liver disease (NAFLD) is consistently linked to insulin resistance which has dietary implications and (2) circulating alanine aminotransferase (ALT) levels are reasonable markers predicting NAFLD status. In a recent cross-sectional study employing nondiabetic subjects, ALT values rose steadily within a normal range early in the life cycle but begin decreasing steadily around age 65 years.Objectives: Because of important nutritional implications, the association between ALT levels and aging in a significantly larger population of healthy volunteers was examined for corroborative purposes. A secondary goal was to gain further knowledge concerning mechanisms behind any age-related decline in ALT activity.Methods: Baseline data from over 10,000 physician-approved, nondiabetic subjects (age 21-84 years) of both genders who had volunteered for previous clinical investigations were assessed.Results: In this cross-sectional examination, the line of best fit (weighted) for average yearly circulating ALT levels displayed an upward surge from ages 21 to 64 years with a discernible steady downward decline around 65 years-mimicking earlier results. Examining linear lines of correlation in the younger and older age groups, the following calculations were determined: a significant positive slope for 21 to 64 years, r = 0.42, n = 44, p < 0.005, and a trending negative slope for 65 and beyond, r = -0.43, n = 20, p < 0.057. Using this same datum base, the correlations between age and fasting blood glucose (FBG) mimicked the ALT results by once more showing a similar upward rise in the younger and a steady decline the older group of volunteers.Conclusions: A paradoxical downward age-related (≥ 65 years) decline of circulating ALT coinciding with a comparable steady decrease in FBG levels was replicated in a larger population of volunteers. The close association of these two chemistries along with other findings suggest that altered glucose-insulin metabolism may participate via "survivor bias" in the ubiquitously found age-related decline of serum ALT-suggesting that nutritional measures could advance optimal health over the life-span.

Assessing biological aging following systemic administration of bFGF-supplemented adipose-derived stem cells with high efficacy in an experimental rat model

Biological aging (BA) is a tool for comprehensive assessment of individual health status. A rat model was developed for measuring BA by intravenously administering adipose-derived stem cells (ADSCs) into rats and evaluating several biochemical parameters. In addition, the effect of basic fibroblast growth factor (bFGF) on the differentiation potential of ADSCs was analyzed. A total of 12 male Sprague Dawley rats were divided into autologous ADSC administration (n=6) and saline administration (n=6) groups. The ADSC administration group was further divided into the bFGF supplemented (n=3) and bFGF non-supplemented (n=3) groups. Biochemical parameters and antioxidant potential were evaluated prior to fat harvest and ADSC administration, as well as 1, 3, and 5 weeks following ADSC administration. ADSC administration regulated inflammation, renal and hepatic functions, and levels of antioxidant enzymes. The cell doubling time of the bFGF-supplemented group was shorter (P=0.0001) than that of the bFGF non-supplemented group. Renal and hepatic functions were maintained with bFGF supplementation, which possibly enhanced the effect of ADSCs. The rat model developed in the present study may promote better understanding of BA in the context of bFGF-supplemented ADSC administration.

Factors influencing longitudinal changes of circulating liver enzyme concentrations in subjects randomized to placebo in four clinical trials

Liver enzyme concentrations are measured as safety end points in clinical trials to detect drug-related hepatotoxicity, but little is known about the epidemiology of these biomarkers in subjects without hepatic dysfunction who are enrolled in drug trials. We studied alanine and aspartate aminotransferase (ALT and AST) in subjects randomized to placebo who completed assessments over 36 mo in a cardiovascular outcome trial [the Stabilisation of Atherosclerotic Plaque by Initiation of Darapladib Therapy ("STABILITY") trial; n = 4,264; mean age: 64.2 yr] or over 12 mo in three trials that enrolled only subjects with type 2 diabetes (T2D) [the DIA trials; n = 308; mean age: 62.4 yr] to investigate time-dependent relationships and the factors that might affect ALT and AST, including body mass index (BMI), T2D, and renal function. Multivariate linear mixed models examined time-dependent relationships between liver enzyme concentrations as response variables and BMI, baseline T2D status, hemoglobin A_1c levels, and renal function, as explanatory variables. At baseline, ALT was higher in individuals who were men, <65 yr old, and obese and who had glomerular filtration rate (GFR) >60 ml·min^-1·1.73 m^-2. ALT was not significantly associated with T2D at baseline, although it was positively associated with HbA_1c. GFR had a greater impact on ALT than T2D. ALT concentrations decreased over time in subjects who lost weight but remained stable in individuals with increasing BMI. Weight change did not alter AST concentrations. We provide new insights on the influence of time, GFR, and HbA_1c on ALT and AST concentrations and confirm the effect of sex, age, T2D, BMI, and BMI change in subjects receiving placebo in clinical trials. NEW & NOTEWORTHY Clinical trials provide high-quality data on liver enzyme concentrations from subjects randomized to placebo that can be used to investigate the epidemiology of these biomarkers. The adjusted models show the influence of sex, age, time, renal function, type 2 diabetes, HbA_1c, and body mass index on alanine aminotransferase and aspartate aminotransferase concentrations and their relative importance. These factors need to be considered when assessing potential signals of hepatotoxicity in trials of new drugs and in clinical trials investigating subjects with nonalcoholic fatty liver disease.

Reflecting on Concepts Relevant to Contemplating the Relationships Between Glucose-Insulin Perturbations, Nutrition, and Aging

Background: Medical professionals attribute a crucial role in the development of several age-related, chronic health maladies to glucose-insulin perturbations - particularly, discernible insulin resistance (IR). However, little information is available concerning the degree to which relatively minor changes in IR participate over time in overall aging population, e.g., when circulating glucose and/or insulin concentrations are consistently within the higher end of normally accepted ranges. Objective: Obtaining precise knowledge is important, because proper nutritional management has the distinct capability of ameliorating the consequences. Methods: Five key concepts are suggested to underpin current thinking as to the applicable mechanisms and these are (1) the practical use of fasting blood glucose (FBG) levels as an estimate of IR, (2) the potential role of even slightly aberrant insulin regulation over time in the aging process, (3) the implementation of "continuum of risks" rather than checkpoints in considering prevention, (4) the presence and meaning of an aging paradox discovered in a recent study, and (5) the importance nutritional considerations in the "deadly triangle" as key factors in aging. Conclusions: Maintaining relatively low levels of FBG representing IR during aging via nutritional means has the potential to deliver a longer, more healthful lifespan as well as ameliorate many adverse manifestations of aging.

Sex-Specific Association between Metabolic Abnormalities and Elevated Alanine Aminotransferase Levels in a Military Cohort: The CHIEF Study

The association of metabolic syndrome (MetS) components with elevated serum alanine aminotransferase (ALT) levels, a marker of hepatic injury, may differ between men and women. However, the sex-specific association in a military young population which has a low prevalence of MetS was unclear. We conducted a cross-sectional examination in 6738 men and 766 women, aged 18-50 years, from the cardiorespiratory fitness study in armed forces (CHIEF) in eastern Taiwan. The components of MetS were defined according to the updated International Diabetes Federation (IDF) ethnic criteria for Asians. Elevated ALT levels were defined as ≥40 U/L for both sexes and ≥30 U/L for women alternatively. Multivariate logistic regression analysis was performed to determine the sex-specific association between MetS components and elevated ALT. The prevalence of MetS and elevated ALT in men were 11.9% and 12.7% respectively, and in women were 3.5%, and 3.8% respectively. In men, high-density lipoprotein < 40 mg/dL, blood pressures ≥ 130/85 mmHg, serum triglycerides ≥ 150 mg/dL, and waist size ≥ 90 cm were associated with elevated ALT (odds ratios (OR) and 95% confidence intervals: 1.59 (1.34-1.90), 1.40 (1.19-1.65), 2.00 (1.68-2.39), and 1.68 (1.38-2.04); all p < 0.001); whereas in women, only fasting plasma glucose ≥ 100 mg/dL was associated with elevated ALT ≥ 40 U/L (OR: 7.59 (2.35-24.51), p = 0.001) and ALT ≥ 30 U/L (2.67 (0.89-7.95), p = 0.08). Our findings suggest that the relationship between metabolic abnormalities and elevated ALT may differ by sex, possibly due to the MetS more prevalent in young adult men than in women.

Increased severity of liver fat content and liver fibrosis in non-alcoholic fatty liver disease correlate with epicardial fat volume in type 2 diabetes: A prospective study

OBJECTIVES

To determine whether severity of non-alcoholic fatty liver disease (NAFLD) and liver fibrosis quantitatively assessed in individuals with diabetes mellitus (DM)-2 correlate with increased coronary heart disease (CHD) risk using non-invasive markers.

METHODS

We conducted a single-centre, prospective, cross-sectional study in 100 consecutive diabetic individuals without known CHD recruited between March 2013 and September 2014. History, physical examination, serum markers, cardiac computed tomography (CT), magnetic resonance (MR) imaging-estimated proton density fat fraction (PDFF) and MR elastography (MRE) were obtained for 95 participants. Written informed consent was provided. Institutional review board approved this study. Spearman rank correlation was performed to assess for correlations. Multiple linear regression model determined independent predictors of epicardial adipose tissue (EAT) volume.

RESULTS

A p value < 0.05 determined statistical significance. The EAT volume was higher in the NAFLD group, defined as MR-imaging PDFF ≥ 5 %, compared to the non-NAFLD group (126.5 ml (IQR 80.9) versus 85.4 ml (IQR 44.7), p=0.002). MR imaging-PDFF correlated with EAT (r=0.42, p < 0.0001). MR imaging-PDFF and liver fibrosis were independently associated with EAT.

CONCLUSIONS

Higher liver fat content and liver fibrosis may portend worse cardiovascular risk in diabetics.

KEY POINTS

• EAT volume is higher in diabetic individuals with NAFLD. • Liver fat content is positively correlated with EAT. • Liver fat content and liver fibrosis were independently associated with EAT. • Higher liver fat content and fibrosis may adversely affect cardiovascular risk.

Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis

OBJECTIVES

Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD.

METHODS

Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (FIB-4), and NAFLD fibrosis score (NFS) for advanced fibrosis (stage F3-F4) for each group was assessed using liver biopsy as the standard.

RESULTS

Six hundred and thirty-four patients were included. The diagnostic accuracy of the AST/ALT ratio was lower than NFS and FIB-4 in all the age groups. The AST/ALT ratio, NFS, and FIB-4 score performed poorly for a diagnosis of advanced fibrosis in those aged ≤35 years (area under the receiver operating characteristic curves (AUROCs 0.52, 0.52, and 0.60, respectively). For all groups >35 years, AUROCs for advanced fibrosis were similar for the NFS and FIB-4 score (range 0.77-0.84). However, the specificity for advanced fibrosis using the FIB-4 and NFS declined with age, becoming unacceptably low in those aged ≥65 years (35% for FIB-4 and 20% for NFS). New cutoffs were derived (and validated) for those aged ≥65 years, which improved specificity to 70% without adversely affecting sensitivity (FIB-4 2.0, sensitivity 77%; NFS 0.12, sensitivity 80%).

CONCLUSIONS

The NFS and FIB-4 scores have similar accuracy for advanced fibrosis in patients aged >35 years. However, the specificity for advanced fibrosis is unacceptably low in patients aged ≥65 years, resulting in a high false positive rate. New thresholds for use in patients aged ≥65 years are proposed to address this issue.

Complex association of serum alanine aminotransferase with the risk of future cardiovascular disease in type 2 diabetes

BACKGROUND AND AIMS

We aimed to determine the prospective association between baseline serum levels of alanine aminotransferase (ALT) and the incident cardiovascular disease (CVD) in people with type 2 diabetes.

METHODS

In an open cohort setting, people with type 2 diabetes were followed for their first ever CVD presentation from 1995 to 2015. Statistical methods included Cox regression analysis for reporting of hazard ratios (HRs), artificial neural network modelings, and risk reclassification analyses.

RESULTS

We found a nearly constant CVD hazard with baseline serum ALT levels below the 30 IU/L mark, whereas baseline serum ALT levels ≥ 30 IU/L remained an independent predictor of lower CVD rates in patients with type 2 diabetes in the final multivariate Cox proportional hazards regression model (HR: 0.204, 95%CI [0.060-0.689], p_{for trend} value = 0.006). Age, male gender and fasting plasma insulin levels independently predicted baseline serum ALT ≥ 30 IU/L among the population cohort. Augmentation of serum ALT into the weighted Framingham risk score resulted in a considerable net reclassification improvement (NRI) of coronary heart disease (CHD) risk prediction in the study population (NRI = 9.05% (8.01%-10.22%), p value < 0.05).

CONCLUSIONS

Serum ALT could successfully reclassify about 9% of the population with type 2 diabetes across the CHD-affected and CHD-free categories. Overall, our findings demonstrate a complex and nonlinear relationship for the risk of future CVD by baseline serum ALT levels in patients with type 2 diabetes. Further studies are warranted to confirm whether this complex association could be translated into a clearly visible U or J-shaped figure.

Association of Nonalcoholic Fatty Liver Disease With Visceral Adiposity but Not Coronary Artery Calcification in the Elderly

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is related closely to risk factors for coronary artery disease, but it is unclear whether NAFLD independently contributes to atherosclerosis. We investigated the association between NAFLD and coronary artery calcium (CAC) scores, determined based on noncontrast cardiac computed tomography data, in an elderly cohort.

METHODS

We conducted a longitudinal, cross-sectional study of data from 250 participants (mean age, 67.6 ± 7.0 y; 43.2% men) in the Rancho Bernardo Study-a prospective population-based study of mostly white adults in suburban Southern California. We compared CAC scores, liver-to-spleen attenuation ratio, and volumes of visceral adipose tissue (VAT) at baseline and after a 5-year follow-up period.

RESULTS

We assigned participants to groups based on CAC scores (0, 0-10, 11-100, 101-400, and >400). Among groups, the liver-to-spleen attenuation ratio did not vary significantly, but VAT increased with CAC score (median and interquartile range values were as follows: 50.0 [33.3-77.4] cm(3), 63.0 [33.9-93.1] cm(3), 66.1 [48.2-80.2] cm(3), 69.1 [48.1-85.0] cm(3), 76.1 [53.1-108.5] cm(3) for CAC groups; P = .0054). In multivariable regression analysis, NAFLD at baseline was not associated with an increased risk of a CAC score greater than 0. Longitudinal analysis showed that visceral fat, but not hepatic steatosis, increased in participants with increasing CAC scores (interquartile range 57.1-92.4) vs 55.2 cm(3) in patients without (interquartile range 36.5-81.1, P = .0401). The proportion of patients with NAFLD decreased after the 5-year follow-up period (from 29.3% before to 14.1% afterward; P = .0081), despite increased mean CAC scores and VAT volume in patients.

CONCLUSIONS

In adults age 67.6 ± 7.0 years, the proportion with NAFLD decreased despite increasing CAC score and VAT with age. There was no clear association between NAFLD and CAC score. However, VAT was associated with baseline and increasing CAC scores. Visceral adiposity therefore might be a risk factor for coronary artery disease.

Obesity and the extent of liver damage among adult New Zealanders: findings from a national survey

Objective

Non‐alcoholic fatty liver disease (NAFLD), defined as excessive fat accumulation in hepatocytes when no other pathologic causes are present, is an increasingly common obesity‐related disorder. We sought to describe the prevalence of elevated liver enzymes, a marker of liver damage, among New Zealand adults, and high‐risk subgroups including those with an elevated body mass index and those with pre‐diabetes or diabetes, to gain a better understanding of the burden of liver disease.

Methods

A total of 4,721 New Zealanders aged 15+ years participated in a nationally representative nutrition survey. Liver enzymes, alanine transaminase (ALT) and gamma glutamyl transpeptidase (GGT) were measured in serum. Results were available for 3,035 participants, of whom 10.8% were Māori and 4.5% Pacific.

Results

Overall, the prevalence of elevated ALT and elevated GGT was 13.1% (95% confidence interval [CI]: 11.2 – 15.0) and 13.7% (95% CI: 12.0 – 15.4), respectively. Odds ratios for an elevated ALT or GGT markedly increased with increasing body mass index. Men with obesity had the highest elevated ALT prevalence (28.5%; 95% CI: 21.7–35.4), and women with diabetes had the highest elevated GGT prevalence (36.5%; 95% CI: 26.0–47.0). Adding alcohol consumption categories to each of the adjusted models did not meaningfully change any results, although for women, heavy alcohol consumption was associated with an elevated GGT (overall p = 0.03).

Conclusions

Obesity‐related liver disease is likely to increasingly burden the New Zealand health sector and contribute to health disparities unless effective obesity treatment and prevention measures are given high priority. © 2015 The Authors. Obesity Science & Practice published by John Wiley & Sons Ltd, World Obesity and The Obesity Society.

Alanine aminotransferase and mortality in patients with type 2 diabetes (ZODIAC-38)

INTRODUCTION

Combined data suggest a bimodal association of alanine aminotransferase (ALT) with mortality in the general population. Little is known about the association of ALT with mortality in patients with type 2 diabetes. We therefore investigated the association of ALT with all-cause, cardiovascular and noncardiovascular mortality in patients with type 2 diabetes.

DESIGN

A prospective study was performed in patients with type 2 diabetes, treated in primary care, participating in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study. Cox regression analyses were performed to determine the associations of log2 -transformed baseline ALT with all-cause, cardiovascular and noncardiovascular mortality.

RESULTS

In 1187 patients with type 2 diabetes (67 ± 12 years, 45% female), ALT levels were 11 (8-16) U/L. During median follow-up for 11.1 (6.1-14.0) years, 553 (47%) patients died, with 238 (20%) attributable to cardiovascular causes. Overall, ALT was inversely associated with all-cause mortality (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.72-0.92), independently of potential confounders. This was less attributable to cardiovascular mortality (HR 0.87; 95% CI 0.72-1.05), than to noncardiovascular mortality (HR 0.77; 95% CI 0.65-0.90). Despite the overall inverse association of ALT with mortality, it appeared that a bimodal association with all-cause mortality was present with increasing risk for levels of ALT above normal (P = 0.003).

DISCUSSION

In patients with type 2 diabetes, low levels of ALT are associated with an increased risk of all-cause mortality, in particular noncardiovascular mortality, compared to normal levels of ALT, while risk again starts to increase when levels are above normal.

Hepatic Enzyme's Reference Intervals and Their Modulating Factors in Western Indian Population

The reference intervals (RIs) of serum aminotransferases and Gamma-glutamyl transferase (GGT) have been established many years ago. Recent RIs are not available. The prospective study was conducted to re-evaluate the RIs of liver enzymes and the effect of demographic and anthropometric variables on them in western Indian population. A total of 1059 blood donors comprised the study population. Anthropometry and serum liver enzymes levels were measured. Subjects were categorized into normal weight and overweight by using body mass index (BMI) and waist circumference (WC). For RI determination, non-parametric methodology recommended by IFCC/CLSI was adopted. Mann-Whitney test and Spearman's rank correlation were used for statistical analysis. Upper limit of normal reference value of liver enzymes were lower in female compared to male. (ALT-23.55 F vs 36.00 M, GGT-34.58 F vs 36.20 M) When RI of liver enzymes were calculated according to body mass index, the upper limit of normal of ALT and GGT were higher in overweight group compared to normal weight group. (ALT-38.00 vs 27.00 IU/L and GGT-37.59 vs 35.26 IU/L). In both male and female, liver enzymes correlated significantly with age. WC and BMI were positively correlated with AST, ALT and GGT in both subgroups and the correlation was stronger in male. Demographic factors should be considered for making liver enzyme tests more clinically relevant. Gender based partitioning should be adopted for serum alanine aminotransferase (ALT) and GGT reference values for Western Indian population.

Liver function parameters in hip fracture patients: relations to age, adipokines, comorbidities and outcomes

AIM

To asses liver markers in older patients with hip fracture (HF) in relation to age, comorbidities, metabolic characteristics and short-term outcomes.

METHODS

In 294 patients with HF (mean age 82.0±7.9 years, 72.1% women) serum alanine aminotransferase (ALT), gammaglutamyltransferase (GGT), alkaline phosphatase (ALP), albumin, bilirubin, 25(OH)vitaminD, PTH, calcium, phosphate, magnesium, adiponectin, leptin, resistin, thyroid function and cardiac troponin I were measured.

RESULTS

Elevated ALT, GGT, ALP or bilirubin levels on admission were observed in 1.7%-9.9% of patients. With age GGT, ALT and leptin decrease, while PTH and adiponectin concentrations increase. Higher GGT (>30 U/L, median level) was associated with coronary artery disease (CAD), diabetes mellitus (DM), and alcohol overuse; lower ALT (≤20 U/L, median level) with dementia; total bilirubin>20 μmol/L with CAD and alcohol overuse; and albumin>33 g/L with CAD. Multivariate adjusted regression analyses revealed ALT, ALP, adiponectin, alcohol overuse and DM as independent and significant determinants of GGT (as continuous or categorical variable); GGT for each other liver marker; and PTH for adiponectin. The risk of prolonged hospital stay (>20 days) was about two times higher in patients with GGT>30 U/L or adiponectin>17.14 ng/L (median level) and 4.7 times higher if both conditions coexisted. The risk of in-hospital death was 3 times higher if albumin was <33 g/L.

CONCLUSIONS

In older HF patients liver markers even within the normal range are associated with age-related disorders and outcomes. Adiponectin (but not 25(OH)vitaminD, PTH, leptin or resistin) is an independent contributor to higher GGT. Serum GGT and albumin predict prolonged hospital stay and in-hospital death, respectively. A unifying hypothesis of the findings presented.

Determinants of alanine aminotransferase levels in a large population from Southern Italy: relationship between alanine aminotransferase and age

BACKGROUND

Determinants of alanine aminotransferase levels have never been investigated in real-life settings. The relationship between alanine aminotransferase and age remains controversial. We evaluated epidemiological, anthropometric, and metabolic factors associated with alanine aminotransferase, focusing on the relationship between alanine aminotransferase and age.

METHODS

A 5-year retrospective analysis was performed on data recorded by 120 general practitioners from Naples (Italy), caring for 170,000 subjects. Exclusion criteria were age <18 years, diagnosis of chronic liver disease, positive markers for viral hepatitis, alcohol abuse, and alanine aminotransferase >100UI/L.

RESULTS

44,232 subjects were enrolled (42.7% males, mean age 56±18 years). Alanine aminotransferase showed independent direct associations with body mass index, glycaemia, cholesterol, and triglycerides (p<0.001), and inverse associations with high-density lipoprotein cholesterol (p<0.001) and creatinine (p<0.01). The relationship between alanine aminotransferase and age was better expressed by polynomial regression (r=0.18, p<0.001), creating an inverted parabola. Mean alanine aminotransferase increased until the third decade in males and the fifth in females, with a subsequent progressive decrease in both genders. The inverse association between alanine aminotransferase and age in older subjects was independent from metabolic factors.

CONCLUSIONS

This real-life setting study, supports the concept that dysmetabolism is a strong determinant of liver injury. Based on our data, a reduction of the standard upper limit of normal alanine aminotransferase should be considered for older subjects.

Complex association between alanine aminotransferase activity and mortality in general population: a systematic review and meta-analysis of prospective studies

Objective

Controversy exists in using alanine aminotransferase (ALT) activity for predicting long-term survival. Therefore, this research study investigated the association between ALT activity and mortality through a systematic review and meta-analysis of previous prospective studies.

Methods

Electronic literature databases, including PubMed, Embase, and the Institute for Scientific Information (ISI), were searched for relevant prospective observational studies (published before Dec 30, 2013) on the association between baseline ALT activity and ensuing all-cause/disease-specific mortality. Information on nationality, sample size, participant characteristics, follow-up duration, comparison, outcome assessment, hazard ratios (HRs) and adjusted covariates was extracted. Pooled HRs and corresponding 95% confidence intervals (CIs) were separately calculated for categorical risk estimates (highest vs. lowest ALT categories) and continuous risk estimates (per 5 U/l of ALT increment) in subgroups separated by age (<70/≥70 years).

Results

A total of twelve prospective cohort studies, totaling 206,678 participants and 16,249 deaths, were identified and analyzed. In the younger age group, the pooled HR for mortality related to liver-disease was about 1.24 (95% CI: 1.23–1.25) per 5 U/l of ALT increment. The dose-response HRs of all-cause mortality, cardiovascular (CV) disease-related mortality, and cancer-related mortality were 0.91 (0.88–0.94), 0.91 (0.85–0.96), 0.92 (0.86–0.98) respectively per 5 U/l of ALT elevation, with insignificant heterogeneity in the older population. There was an approximate decrease of 4‰ observed on HRs of all-cause, CV-related, and cancer-related mortality followed with one year's increment through meta-regression (all P<0.05).

Conclusions

The ALT-mortality association was inconsistent and seems particularly susceptible to age after synthesizing the previous prospective studies. In terms of the age, ALT activity was more valuable in predicting mortality in the older population; extremely low ALT levels indicated a higher all-cause, CV-related, and cancer-related mortality. ALT activity may therefore be a useful biomarker when predicting the long-term survival of elderly patients.

Association of serum bilirubin with aging and mortality

BACKGROUND AND AIMS

Bilirubin, a breakdown product of heme metabolism, has been shown to be protective against cardiovascular mortality; however, it is also a marker of liver function. There are limited data on the longitudinal changes in bilirubin with aging in a population-based cohort of older adults. This study was designed to determine whether serum bilirubin changes with age in older adults, and to evaluate whether age attenuates the association between bilirubin and mortality.

METHODS

This is a prospective cohort study of 2364 participants with a mean age of 70 years, who completed a research clinic visit from 1984 to 1987, and 1703 participants who returned for a second research visit approximately 8 years later. Cross-sectional and longitudinal multivariable-adjusted analyses were performed to examine the association between serum bilirubin, aging, and mortality.

RESULTS

In cross-sectional analyses, when the cohort was divided into quartiles of age, higher baseline serum bilirubin levels were associated with older age in analyses adjusted for sex, body mass index (BMI), alanine aminotransferase (ALT), albumin, and metabolic traits (P-value <0.001). In longitudinal analyses, among the subset of participants who had two research visits, aging remained significantly associated with an increase in bilirubin in multivariable-adjusted models (P-value <0.0001). When the longitudinal cohort was divided into bilirubin quartiles, Kaplan-Meier analysis showed an incremental reduction in survival with higher bilirubin levels (P-value = 0.002); however, this association between bilirubin quartile and mortality was no longer significant after adjusting for age (P-value 0.30), suggesting higher bilirubin in older age does not confer survival advantage.

CONCLUSIONS

Serum bilirubin levels gradually increase with age in older adults. Elevated bilirubin in older individuals is not associated with improved survival as previously reported in middle-aged populations.

Effects of age and sex on the hematology and blood chemistry of Tibetan macaques (Macaca thibetana)

Tibetan macaques (Macaca thibetana), also known as Chinese stump-tailed macaques, are a threatened primate species. Although Tibetan macaques are Old World monkeys in the genus of Macaca, limited age- and sex-related physiologic data are available for this particular species. We used 69 apparently healthy Tibetan male and female macaques to explore the effect of age and sex on physiologic parameters. Somatometric measurements, biochemistry, and hematologic parameters were analyzed. Significant age-related differences were found for weight, BMI, RBC count, Hgb, Hct, neutrophils, eosinophil count, ALT, AST, ALP, GGT, creatine kinase (muscle and brain subtypes), LDH, α-amylase, creatinine, apolipoprotein A1, total protein, albumin, cholesterol, HDL, and potassium. Significant differences by sex were noted for weight, BMI, ALT, total bilirubin, and indirect bilirubin. An interaction between age and sex accounted for statistically significant differences in the values for weight, BMI, and lymphocyte and eosinophil counts. These physiologic data will provide veterinarians and researchers with important age- and sex-specific reference ranges for evaluating experimental results from Tibetan macaques.

Alanine aminotransferase-old biomarker and new concept: a review

Measurement of serum alanine aminotransferase (ALT) is a common, readily available, and inexpensive laboratory assay in clinical practice. ALT activity is not only measured to detect liver disease, but also to monitor overall health. ALT activity is influenced by various factors, including viral hepatitis, alcohol consumption, and medication. Recently, the impact of metabolic abnormalities on ALT variation has raised concern due to the worldwide obesity epidemic. The normal ranges for ALT have been updated and validated considering the metabolic covariates in the various ethnic districts. The interaction between metabolic and demographic factors on ALT variation has also been discussed in previous studies. In addition, an extremely low ALT value might reflect the process of aging, and frailty in older adults has been raised as another clinically significant feature of this enzyme, to be followed with additional epidemiologic investigation. Timely updated, comprehensive, and systematic introduction of ALT activity is necessary to aid clinicians make better use of this enzyme.

Higher fetuin-A level is associated with coexistence of elevated alanine aminotransferase and the metabolic syndrome in the general population

BACKGROUND

Higher fetuin-A levels have been linked to fatty liver disease (FLD), the most common cause of elevated alanine aminotransferase (ALT) levels, but associations between ALT and fetuin-A level have been inconsistent. The presence of the metabolic syndrome in individuals with elevated ALT levels has been shown to characterize more severe FLD. Thus, aim of the study was to investigate the association between fetuin-A level and the coexistence of elevated ALT levels and metabolic syndrome (ALT-MetS).

METHODS

A population-based cross-sectional study including 728 individuals (age 50-77 years) was conducted. We used multivariable logistic regression analysis to assess the association between serum fetuin-A level and the dichotomous outcome ALT-MetS, defined as coexistence of elevated ALT level (>75th percentile) and metabolic syndrome (any three of the components: abdominal obesity, elevated triglycerides, reduced high-density lipoprotein cholesterol, elevated blood pressure, abnormal glucose metabolism).

RESULTS

Individuals with a high fetuin-A level had an odds ratio (OR) for ALT-MetS of 2.22 [95% confidence interval (CI) 1.36-3.63; Ptrend=<0.001] comparing extreme tertiles. After excluding individuals with cancer, stroke, or myocardial infarction, individuals with high fetuin-A levels had an OR for ALT-MetS of 2.48 (95% CI 1.38-4.47) comparing extreme tertiles, and we observed statistical interaction between fetuin-A level and age (P=0.048). Fetuin-A level was associated with ALT-MetS in young individuals, defined as <64 years of age (OR 3.30, 95% CI 1.45-7.55; Ptrend=0.004), and not statistically significant in older individuals (OR 1.79, 95% CI 0.74-4.31; Ptrend=0.197).

CONCLUSIONS

Fetuin-A level was positively associated with ALT-MetS, particularly in younger individuals. Prospective studies in larger populations are warranted.