Upper reference limits for aminotransferase activities and the prevalence of elevated aminotransferase activities in a Korean population

Bioelectrical impedance analysis parameters are superior to liver enzymes in predicting metabolic dysfunction-associated steatotic liver disease in young adults

BACKGROUND/AIMS

The predictive value of bioelectrical impedance analysis (BIA) parameters and liver enzymes for metabolic dysfunction-associated steatotic liver disease (MASLD) in young adults is unclear. We aimed to investigate the usefulness of BIA parameters and liver enzymes in MASLD screening in young adults.

METHODS

Overall, 2,647 participants aged 19-30 years were evaluated by sex. Logistic regression analyses were performed with MASLD as the dependent variable. Receiver operating characteristic (ROC) curves were used to compare the predictive ability for MASLD.

RESULTS

In males, percentage body fat (PBF), total body fat (TBF), visceral fat area (VFA), abdominal subcutaneous fat (ASF), alanine aminotransferase (ALT), and elevated ALT levels were positively associated with MASLD, whereas skeletal muscle index (SMI) and AST/ALT were negatively associated after adjusting for age, body mass index, and moderate physical activity. In females, PBF, TBF, ASF, AST, ALT, low SMI (LSMI), and elevated ALT levels were positively associated with MASLD, whereas SMI and AST/ALT were negatively associated. The areas under the ROC curves (AUCs) of PBF, TBF, VFA, ASF, SMI, AST, ALT, and AST/ALT were 0.818, 0.837, 0.834, 0.837, 0.818, 0.653, 0.759, and 0.790 respectively, in males. In females, the corresponding values were 0.915, 0.939, 0.934, 0.940, 0.915, 0.620, 0.799, and 0.849 respectively. The AUC of LSMI was significantly higher than that of increased ALT levels in females.

CONCLUSIONS

BIA parameters and ALT levels are useful for predicting MASLD in young adults. BIA parameters have superior predictive ability than liver enzymes.

Blood Concentrations of Lead, Cadmium, and Mercury Are Associated With Alcohol-Related Liver Disease

BACKGROUND

An association between environmental pollutants and alcohol-related liver disease (ALD) has not been determined until now. The objectives of this study were to examine the association of the pollutants with ALD, and whether the pollutants together increased the risk of ALD.

METHODS

Data were extracted from the Korea National Health and Nutrition Examination Survey (2010-2013 and 2016-2017; n = 11,993). Blood levels of lead, cadmium, and mercury were measured. ALD was defined by a combination of excessive alcohol consumption and ALD/non-alcoholic fatty liver disease index > 0. The aspartate aminotransferase-to-platelet ratio index and fibrosis (FIB)-4 score were used to evaluate ALD FIB.

RESULTS

The odds ratios (ORs) of ALD for the highest versus the lowest quartiles of exposure were for lead, 7.39 (95% confidence interval [CI], 5.51-9.91); cadmium, 1.68 (95% CI, 1.32-2.14); and mercury, 5.03 (95% CI, 3.88-6.53). Adjusting for age, gender, smoking, occupation, education, and personal income attenuated the associations but indicated significant positive trends (all Ptrend < 0.001). A positive additive interaction between cadmium and lead was observed. The relative excess OR due to the interaction was 0.96 (95% CI, 0.41-1.51); synergy index = 2.92 (95% CI, 0.97-8.80). Among 951 subjects with ALD, advanced FIB was associated with lead and cadmium (OR, 3.46, 95% CI, 1.84-6.53; OR, 8.50, 95% CI, 2.54-28.42, respectively), but not with mercury. The effect estimates for lead and cadmium remained significant even after adjustment for daily alcohol intake.

CONCLUSION

Blood levels of lead, cadmium, and mercury were significantly associated not only with the risk of ALD but also with ALD FIB. Cadmium and lead have synergistic effects that increase the risk of ALD.

Age Dependence of Liver Enzymes: An Analysis of Over 1,300,000 Consecutive Blood Samples

BACKGROUND & AIMS

Upper levels of normal for alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyltransferase (GGT) generally take sex into account, but not age. This simplification may lead to misclassification and burden the patient and health system unnecessarily.

METHODS

Consecutive blood samples were analyzed from a German laboratory. Subcohorts included samples from a prescribed routine check-up and a healthy cohort, defined as patients without increased GGT, triglyceride, cholesterol, glycated hemoglobin, or glucose levels, and without known hepatitis B.

RESULTS

A total of 1,369,180 blood samples were analyzed from 601,779 participants (50.8% female; mean age, 58.5 y; SD, 18.0 y). There is an extreme age dependence in ALT values for men: increased values were seen in 20.0% (95% CI, 19.5%-20.4%) of patients in the age group of 25 to 34 years, but only 6.7% (95% CI, 6.4%-7.0%) for the ages of 65 to 74 years. The 95th percentile reaches values greater than 80 U/L instead of 50 U/L at the age of 35, and decrease to less than 50 U/L by the age of 75. Similar qualitative results were found in the healthy and prescribed routine check-up subcohorts. The age dependence is much weaker for ALT in women. The proportion of women with an increased AST level increases from approximately 6% to 12% at approximately age 50. The 95th percentile for GGT increases up to the age of 60 in men, and throughout life in women.

CONCLUSIONS

Current guidelines and reference values for ALT imply that subsequent diagnostics are needed for a large proportion of young men. Our data strongly suggest that age adaptation should be considered.

Association between environmental exposure to cadmium and risk of suspected non-alcoholic fatty liver disease

AIM

We evaluated the associations between blood Cadmium (Cd) concentrations and risk of suspected NAFLD using nationally representative data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2013, 2016 and 2017.

METHODS

This cross-sectional study included 12,099 adults for the serum alanine aminotransferase (ALT) and hepatic steatosis index (HSI) analyses and 2,904 adults for the serum gamma-glutamyl transferase (GGT) and fatty liver index (FLI) analyses, without significant alcohol consumption. Blood Cd concentrations were measured by graphite furnace atomic absorption spectrometry. Data were analyzed using survey logistic regression models.

RESULTS

Odds ratios (ORs) of suspected NAFLD increased significantly per unit of natural log-transformed blood Cd concentration (OR [95% (CI)], for ALT, overall: 1.50 [1.34, 1.68], men: 1.64 [1.40, 2.10] and women: 1.29 [1.08, 1.47]; for GGT, overall: 1.77 [1.33, 2.35], men: 2.28 [1.53, 3.41] and women: 1.27 [0.82, 1.97]; for FLI, overall: 1.84 [1.32, 2.57], men: 1.91 [1.24, 2.94] and women: 1.58 [0.87, 2.86]; for HSI, overall: 1.19 [1.07, 1.32], men: 1.17 [1.01, 1.37] and women: 1.14 [0.99, 1.32]). The blood Cd concentrations associated with risk of suspected NAFLD were lower than those previously reported (for ALT, > 0.64 μg/L, for GGT, > 1.41 μg/L, for FLI, > 0.96 μg/L, and for HSI, > 1.41 μg/L).

CONCLUSIONS

This study suggests that the reference level of blood Cd should probably be lower than the previously recommended value to prevent adverse health effects due to Cd exposure.

African Americans Demonstrate Significantly Lower Serum Alanine Aminotransferase Compared to Non-African Americans

BACKGROUND AND AIMS

Normal ranges of serum alanine aminotransferase (ALT) may vary by race. However, results from research studies are contradictory, and many of these studies have included only small numbers of African Americans. We investigated ALT values in patients without evidence of liver disease to determine whether normal ranges differ across race groups. We also evaluated whether a race- and sex-dependent upper limit of normal (ULN) would improve the ability of ALT to predict liver disease compared to the sex-dependent ULN currently in use.

METHODS

We identified ICD9 codes for liver conditions and diabetes in medical records from a sample of 6719 patients. Analysis of variance (ANOVA) was used to assess differences in ALT log-transformed distributions by race. Logistic regression was used to evaluate whether the addition of race to the current sex-dependent ULN improves the ability of ALT to predict liver disease (assessed by area under the receiver operating characteristic curve (AUROC)).

RESULTS

Among 1200 patients with BMI 18.5 < 25 and no evidence of liver disease or type 2 diabetes in their medical record, African Americans demonstrated significantly lower ALT (23.47 IU/L; 95% CL 22.87-24.10) than a combined group of Asian American/White/Other patients (25.71 IU/L; 95% CL 24.69-26.77). This difference remained across BMI categories. The race- and sex-dependent model demonstrated significantly better predictive ability than the sex-dependent model (AUROC = 66.6% versus 59.6%, respectively; p < 0.0001).

CONCLUSIONS

In a large, racially diverse sample, African Americans demonstrated significantly lower ALT compared to non-African Americans; this difference remained as BMI increased. The establishment of race-specific normal ranges for ALT could contribute to better screening and care for African American patients.

Upper Normal Limits of Serum Alanine Aminotransferase in Healthy Population: A Systematic Review

BACKGROUND

Measuring serum alanine aminotransferase (ALT) enzyme is a routine clinical test commonly used to evaluate abnormalities in the body in general, and in the liver function in particular. Higher ALT levels are associated with some metabolic disorders. The upper limit normal (ULN) is considered as a reliable threshold for the definition of high ALT.

OBJECTIVES:

To assess the existing evidence on the ULN for ALT in the general population.

DATA SOURCE:

PubMed (Medline), EMBASE, Scopus, and Web of Science (ISI) were searched using a specified search strategy.

ELIGIBILITY CRITERIA:

We collected documents published from 1980 to 2018 in the English language, focusing on human samples at the population level and extracted the data after qualitative evaluation.

METHODS

We conducted this study in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. We used specific search terms and their combinations to find documents from relevant databases. We used a snowballing approach to find documents not captured in the main phase of the search. Two authors separately conducted the search, screened the articles, and selected documents that were qualified for data extraction based on the defined inclusion criteria. Finally, data extraction was conducted by two authors using PRISMA checklist. Reported ULNs for ALT and 95% confidence intervals (CIs) were documented in previously developed datasheets.

RESULTS

Out of 15242 studies, 47 articles were included for data extraction and analysis. Data were sparse and lacked the consistency to precisely estimate ULN for serum ALT. The ULN of ALT was significantly diverse across various geographical locations and sexes. The lowest value of ULN for ALT was 19 IU/L in Chinese children (age range: 7 to < 10 years), and the highest value of ULN for ALT was 55 IU/L in children from Ghana aged < 5 years.

LIMITATIONS:

The main limitation of the current systematic review was the scarcity of the reported measures for ULN of ALT.

CONCLUSION

Based on the results of the current systematic review, it is suggested that the normal range of ALT be redefined, but this redefinition should be done according to the localized data. In order to redefine the ULN for ALT, regional differences, methods used in ALT measurements, and ULN determination should be considered.

Trends in the prevalence of chronic liver disease in the Korean adult population, 1998-2017

Data on the trends in the prevalence of chronic liver disease (CLD) in Korea are scarce. This study aimed to evaluate whether the CLD prevalence changed between 1998-2001 and 2016-2017. Data were extracted from the Korea National Health and Nutrition Examination Survey (1998-2001 to 2016-2017; n=25,893). Non-alcoholic fatty liver disease (NAFLD) was defined as a hepatic steatosis index >36 in the absence of any other evidence of CLD. The definition of alcoholrelated liver disease (ALD) was excessive alcohol consumption (≥210 g/week for men and ≥140 g/week for women) and an ALD/NAFLD index >0. The prevalence of NAFLD increased from 18.6% (95% confidence interval [CI], 17.8-19.5%) in 1998-2001 to 21.5% (95% CI, 20.6-22.6%) in 2016-2017. During the same time period, increases were observed in the prevalence of obesity (27.0 vs. 35.1%), central obesity (29.4 vs. 36.0%), diabetes (7.5 vs. 10.6%), and excessive drinking (7.3 vs. 10.5%). ALD prevalence also increased from 3.8% (95% CI, 3.4-4.2%) to 7.0% (95% CI, 6.4-7.6%). In contrast, chronic hepatitis B decreased from 5.1% (95% CI, 4.6-5.5%) to 3.4% (95% CI, 3.0-3.8%). The prevalence of chronic hepatitis C was approximately 0.3% in 2016-2017. The prevalence of NAFLD and ALD increase among Korean adults. Our results suggest potential targets for interventions to reduce the future burden of CLD.

Lack of association between early menopause and non-alcoholic fatty liver disease in postmenopausal women

Background: The possibility of an association between early menopause and the risk of non-alcoholic fatty liver disease (NAFLD) is as yet unclear.Methods: The subjects consisted of 4354 postmenopausal women who participated in the 2010-2012 Korea National Health and Nutrition Examination Survey. Early, normal, and late menopause were defined as age at menopause <45 years, 45-54 years, and ≥55 years, respectively. NAFLD was defined by a hepatic steatosis index of >36.Results: When compared with normal menopausal women, early or late menopausal women had no significant differences in the odds ratios (ORs) of NAFLD: OR = 1.05, 95% confidence interval (CI), 0.83-1.32 and OR = 1.02, 95% CI, 0.75-1.39, respectively. These results remained similar after adjustment for known risk factors for NAFLD, reproductive factors, and comorbidities. The OR for NAFLD per 1-year increase in age at menopause was 1.01 (95% CI, 0.99-1.03; p = 0.329). The prevalence of advanced fibrosis was 2.1% (95% CI, 0.7-6.4%), 2.2% (95% CI, 1.3-3.8%), and 3.9% (95% CI, 1.2-12.2%) in early, normal, and late menopausal women, respectively.Conclusions: This study provides no evidence for an association of early menopause with NAFLD risk. However, NAFLD-related advanced fibrosis is highly prevalent in postmenopausal women.

Upper Normal Limit of Serum Alanine Aminotransferase and Its Association with Metabolic Risk Factors in Pars Cohort Study

BACKGROUND

The range of serum alanine aminotransferase (ALT) varies in different sub-populations or countries. Its population-specific cut-off points may provide a more effective screening tool for non-alcoholic fatty liver disease (NAFLD). Objectives To investigate the upper normal level (UNL) of ALT and its association with metabolic syndrome (MS) in a semi-urban population in southern Iran.

METHODS

The baseline data of Pars Cohort Study was used. A total of 9264 subjects aged 40-75 years were enrolled. UNL of ALT was estimated based on 95 percentile of ALT in participants who had body mass index (BMI) < 25. Multivariable logistic regression was applied and adjusted odds ratio (OR) and its 95% confidence interval (CI) were estimated.

RESULTS

95 percentile of ALT was 41.71 U/L and 32.9 U/L in men and women, respectively. Abnormal waist circumference (OR: 1.72, 95%CI: 1.34, 2.21), triglyceride (OR: 1.63, 95%CI: 1.25, 2.13), fasting blood sugar (OR: 1.69, 95%CI: 1.32, 2.16), cholesterol level (OR: 1.06, 95%CI: 1.03, 1.09) and systolic blood pressure (OR: 1.08, 95%CI: 1.01, 1.16) were independently associated with ALT.

CONCLUSION

UNL of ALT in southern Iranian women is lower than the current recommended level, while these are almost the same for men. MS components are highly common in southern Iran and are associated with elevated serum ALT. Further studies are recommended to estimate the UNL of serum ALT among the Iranian population with NAFLD.

Influence of non-pathological factors on ALT measurements

Alanine transaminase (ALT) is still the most sensitive marker for evaluating the damage of liver cells. ALT measurements may be affected by common non-pathological factors such as gender, age, pregnancy, different physiological conditions, circadian rhythm, diet, drinking, smoking, strenuous exercise, metabolic factors, drugs, blood collection methods, and specimen collection, transmission, and preservation. It is important to emphasize the definition of limits of normal ALT and the influence of the above-mentioned non-pathological factors on its test results.

Redefining the alanine aminotransferase upper limit of normal improves the prediction of metabolic syndrome risk

BACKGROUND

Multiple studies have recently proposed the lowering of upper limit of normal (ULN) for alanine aminotransferase (ALT) to improve the diagnostic sensitivity for viral hepatitides and metabolic syndrome (MS). We have tried to validate some of the proposed ULNs in the diagnosis of MS.

METHODS

We used data from the HepaMeta Study conducted in 2011 in Slovakia, which explored the prevalence of MS in eastern Slovakia. Patients were tested for the criteria of MS and ALT. Different, previously published, ALT cutoffs were then used to calculate odds' ratios, sensitivity, specificity, and accuracy of MS and its components.

RESULTS

Manufacturers' recommended ULN used in our institution (0.8 µkat/l, 47 U/l for men and 0.6 µkat/l, 35 U/l for women) failed to predict any significant risk of MS. Lowered cutoff (72% of the original ULN) identified the patients with the highest age-adjusted probability of MS (odds ratio 3.194, 95% confidence interval 1.398-7.295). ALT was significantly associated with elevated levels of triacylglycerols, hyperglycemia, and obesity.

CONCLUSION

In patients with MS, one must consider liver involvement if the patient has ALT levels in the upper third of the reference range. There is the need for discussion about the feasibility of lower ALT ULN in clinical practice.

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.

Upper limit of normal for alanine aminotransferase: quo vadis?

Several studies suggest that a substantial number of patients with normal serum alanine aminotransferase (ALT) levels, defined by current thresholds, have ongoing hepatic necro-inflammation and fibrosis, and are at risk of liver disease progression. A major problem lies in the definition of normality. The current upper limit of normal (ULN) for ALT was established in the 1980s when reference populations were likely to include many persons with hepatitis C virus infection and nonalcoholic fatty liver disease. Because ALT may be influenced, not only by liver disease, but also by other medical conditions, changing lifestyle factors and demographic determinants, the current ALT ULN threshold has recently been challenged. This review not only highlights current evidence on why and how ALT ULN should be redefined, but also discusses the current concerns about updating the ULN threshold for ALT.