Association of body mass index with serum alanine aminotransferase in Chinese adolescents: a school-based cross-sectional study

Exposure to volatile organic compounds and polycyclic aromatic hydrocarbons is associated with the risk of non-alcoholic fatty liver disease in Korean adolescents: Korea National Environmental Health Survey (KoNEHS) 2015-2017

Non-alcoholic fatty liver disease (NAFLD) is one of the most frequent liver diseases among adolescents. Several animal studies have suggested that volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) increase NAFLD risk. However, few epidemiological studies have confirmed the association between VOCs, PAHs and NAFLD in the general adolescent population. Therefore, we analyzed 798 adolescents from the Korean National Environmental Health Survey (KoNEHS), 2015-2017, to examine the associations of urinary metabolites of VOCs and PAHs with serum alanine aminotransferase (ALT) activity and NAFLD prevalence. We performed linear regression, logistic regression, and Bayesian kernel machine regression (BKMR) to evaluate the association of urinary VOCs and PAHs metabolites with ALT levels and NAFLD prevalence. After adjusting for all covariates, urinary benzylmercapturic acid and 2-hydroxyfluorene levels were found to increase ALT activity and NAFLD prevalence. Additionally, the BKMR analyses showed a significantly positive overall effect on ALT activity and NAFLD prevalence with urinary concentrations of VOCs and PAHs metabolites, with 2-hydroxyfluorene as the biggest contributor. Our study suggests that exposure to low-level VOCs and PAHs may have a detrimental effect on NAFLD risk in adolescents. Given the increasing prevalence of NAFLD in adolescents, future cohort studies are confirmed to comprehend the effect of these chemicals on NAFLD risk.

Anthropometry did not approach adequate predictive accuracies for detecting elevated fasting plasma glucose or hemoglobin A1c levels among Chinese children aged 7-9 years

AIMS/INTRODUCTION

Elevated concentrations of fasting plasma glucose (FPG) or hemoglobin A1c (HbA1c) are well-established independent risk factors for progression to diabetes, cardiovascular comorbidities and mortality. Most previous studies on the relationships of anthropometric measures with hyperglycemia were carried out among adults and adolescents, but few data are available for the performance predication of the predictors for diagnosing elevated FPG or HbA1c among young children.

MATERIALS AND METHODS

Involving 5,556 students of aged 7-9 years, a school-based cross-sectional survey was carried out between March and June 2019 in Shenzhen, China. Receiver operating characteristic curve analysis was utilized.

RESULTS

The median was 4.6 (interquartile range [IQR] 4.3-4.8) mmol/L for FPG and 5.3% (IQR 5.1-5.5%) for HbA1c levels for all participants. For detecting elevated FPG, weight (0.651, IQR 0.583-0.719) and waist circumference (0.650, IQR 0.584-0.717) showed the highest area under the curve and 95% confidence interval, followed by body mass index and the z-score of body mass index (both 0.635, IQR 0.567-0.703); other anthropometric measures showed poorer diagnostic efficiencies or no ability. For detecting elevated HbA1c, lower efficiencies for the Conicity Index (0.651, IQR 0.583-0.719), waist-to-height ratio, waist-to-hip ratio and waist-to-chest ratio were shown. The correlations of FPG and HbA1c levels with anthropometric indices were weak (Spearman's r ≤ 0.179).

CONCLUSIONS

None of the evaluated anthropometric indicators approached an adequate predictive accuracy for the detection of elevated FPG or HbA1c levels in Shenzhen children aged 7-9 years. The current study did not recommend anthropometry screening for prediabetes in young children.

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.

Diagnostic performance of individual characteristics and anthropometric measurements in detecting elevated serum alanine aminotransferase among children and adolescents

BACKGROUND

Screening for elevated serum alanine aminotransferase (ALAT) can help identifying individuals at the risks of chronic and metabolic diseases, but blood collection is invasive and cannot be widely used for investigations. Considered as simple and inexpensive screening indices, individual characteristics and anthropometric measurements can be measured in a large crowd and may be important surrogate markers for ALAT levels. This study aimed to examine the diagnostic performance of individual characteristics and anthropometric parameters as predictive factors for discerning an elevated ALAT activity among Shenzhen children and adolescents.

METHODS

A school-based screening study was performed from 9 high schools in Shenzhen during February 2017 and June 2018. Receiver operating characteristic curve was used to examine the diagnostic performance of each variable for detecting elevated ALAT.

RESULTS

Altogether 7271 students aged 9-17 years were involved. The proportion of elevated ALAT greatly increased with increasing classification of BMI-z. By the sex-specific cut-offs for elevated ALAT (30 U/L boys; 19 U/L girls), BMI showed the highest area under the curve of 0.789 (95% CI 0.765-0.812) and followed by weight (0.779 [0.755-0.802]), BMI-z (0.747 [0.722-0.772]), height (0.622 [0.597-0.647]), and age (0.608 [0.584-0.632]), while height-z was not capable. With the cut-off of 67.8 kg for weight and 22.6 kg/m2 for BMI, the accuracy to identify elevated ALAT was 87.1% for weight and 82.9% for BMI.

CONCLUSIONS

The presence of elevated ALAT was more common in overweight or obese children and adolescents. BMI and weight had the superiority of detecting elevated ALAT, followed by BMI-z, height, and age.