Higher waist-to-height ratio and waist circumference are predictive of metabolic syndrome and elevated serum alanine aminotransferase in adolescents and young adults in mainland China

Aminotransferase Ratio Is a Useful Index for Hepatosteatosis in Children and Adolescents: A Cross-Sectional Observational Study

Nonalcoholic fatty liver disease (NAFLD) and childhood obesity are emerging global health issues. The aim of this study was to identify a simple predictor of NAFLD in children and adolescents. This community-based study was conducted from December 2012 to September 2013 in Taiwan and included 1,222 children between 10 and 19 years of age. After excluding alcohol consumption and hepatic-related lesions, NAFLD was diagnosed according to sonographic criteria. Potential confounding factors (including age, gender, and anthropometric and laboratory data) were tested by logistic regression analysis. The cutoff value was determined using receiver operating characteristic (ROC) curve analysis. In addition to older age, heavier weight, and wider waist, subjects with NAFLD had significantly higher blood pressure, lipid disturbances, and alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratios. The correlation between NAFLD and ALT/AST ratio remained significant even after adjusting for confounders (adjusted odds ratio [OR], 2.19; 95% confidence interval [CI], 1.24-3.87; p = .007). The risk score of having a fatty liver, based on ALT/AST ratio, was greater than 0.981 according to ROC curve analysis (sensitivity, 60.5%; specificity, 80.3%; area under the curve, 0.756; CI, 0.71-0.80; p < .001). Therefore, ALT/AST ratio may represent a powerful index of hepatosteatosis in children and adolescents.

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.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

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.

The effect of liver enzymes on adiposity: a Mendelian randomization study

Poorer liver function is positively associated with diabetes in Mendelian randomization (MR) studies. Observationally, adiposity is associated with poorer liver function. To clarify the etiology, we assessed the association of liver enzymes with adiposity observationally and using two-sample MR for validation. In the "Children of 1997" birth cohort, we used multivariable linear regression to assess the associations of alanine transaminase (ALT) and alkaline phosphatase (ALP) at ~17.5 years with body mass index (BMI) (n = 3,458). Using MR, genetic predictors of ALT, ALP and gamma glutamyltransferase (GGT), were applied to genome-wide association studies of BMI (n = 681,275), waist circumference (WC) (n = 224,459) and waist-hip ratio (WHR) (n = 224,459) to obtain unconfounded estimates. Observationally, ALT was positively associated with BMI (0.10 kg/m² per IU/L, 95% confidence interval (CI) 0.09 to 0.11). ALP was inversely associated with BMI (-0.018 kg/m² per IU/L, 95% CI -0.024 to -0.012). Using MR, ALT was inversely associated with BMI (-0.14 standard deviation per 100% change in concentration, 95% CI -0.20 to -0.07), but not WC or WHR. ALP and GGT were unrelated to adiposity. Poorer liver function might not cause adiposity; instead higher ALT might reduce BMI, raising the question as to the role of ALT in body composition.

Insulin resistance is associated with elevated transaminases and low aspartate aminotransferase/alanine aminotransferase ratio in young adults with normal weight

OBJECTIVE

The aim of this study is to determine whether insulin resistance is associated with elevation of transaminases levels and aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio in normal-weight healthy young adults.

PARTICIPANTS AND METHODS

Apparently healthy nonpregnant women and men, aged 18-23 years, were enrolled in a cross-sectional study. According to the homeostasis model assessment of insulin resistance, the participants were allocated into groups of patients with (>2.5) and without (≤2.5) insulin resistance. Normal weight was defined by BMI of at least 18.5 and less than 25.0 kg/m. A multiple logistic regression analysis was carried out to determine the association between insulin resistance and elevated transaminases and AST/ALT ratio of 1 or less.

RESULTS

A total of 1732 young adults were enrolled and allocated into groups with (n=287) and without (n=1445) insulin resistance. The prevalence of insulin resistance was 16.6% in the overall population. The multivariate logistic regression analysis adjusted by age, sex, waist circumference, and BMI indicated that the odds ratio (OR) between insulin resistance and elevated ALT concentrations is 1.65 [95% confidence interval (CI): 1.04-2.62, P=0.03], for AST/ALT ratio lower than 1 OR is 1.69 (95% CI: 1.27-2.26, P<0.001), and for elevated AST levels OR is 1.31 (95% CI: 0.71-2.43, P=0.377).

CONCLUSION

The results of the present study suggest that insulin resistance is significantly associated with elevated ALT levels and AST/ALT ratio of lower than 1, but not with elevated AST levels.

Waist-to-height ratio is an appropriate index for identifying cardiometabolic risk in Chinese individuals with normal body mass index and waist circumference

BACKGROUND

The waist-to-height ratio (WHtR), a novel index that has been reported to correlate more strongly than body mass index (BMI) and waist circumference (WC) with cardiometabolic risk factors, has not been studied in Chinese individuals with normal body mass index and waist circumference. The present study compared the predictive power of WHtR with those of BMI and WC for such factors in non-obese Chinese, and to define optimal cutoffs of WHtR in this population.

METHODS

A total of 2137 subjects aged 40-75 years were recruited. Three anthropometric indices (WHtR, BMI, and WC) were compared and the optimal cutoffs of WHtR were identified by receiver operating characteristic curve (ROC) analysis. WHtR was divided into four quartiles (WHtR-Q), and multiple linear regression analyses were used to calculate the relationship between WHtR-Q and clinical biochemical index.

RESULTS

Waist-to-height ratio was more efficient than WC to identify cardiometabolic risk factors in both genders, but was only superior to BMI in females. WHtR-Q was positively correlated with fasting plasma glucose, 2-h postprandial blood glucose, and systolic blood pressure, and negatively connected with high density lipoprotein cholesterol in both genders after controlling for age, current smoking and drinking, moderate-intensity physical activity, daily sedentary time, daily screen time and menopause (only for females). The optimal cutoffs of WHtR for detecting cardiometabolic risk factors were 0.47 in males and 0.51 in females.

CONCLUSION

Waist-to-height ratio might be an effective index to identify cardiometabolic risk factors in Chinese with normal BMI and WC, particularly in females.

Prevalence and risk factors of diabetes and impaired fasting glucose among university applicants in Eastern China: findings from a population-based study

AIMS

To investigate the prevalence and risk factors of diabetes and impaired fasting glucose among urban university applicants in Eastern China.

METHOD

The study uses data from the annual health examination among all students finishing high school who applied for university entrance in Changzhou City in 2012. In total, 6716 students aged 17-19 years had fasting blood glucose, alanine transaminase, height, weight and blood pressure measured. Impaired fasting glucose and diabetes were defined as fasting blood glucose ≥ 5.6 mmol/l (but < 7 mmol/l) and ≥ 7 mmol/l, respectively.

RESULTS

The overall prevalence of impaired fasting glucose and diabetes was 2.40% and 0.13%, respectively (3.67% and 0.09% in boys; 1.09% and 0.18% in girls). In total, 20.9% of boys and 10.6% of girls were overweight/obese. High socio-economic status was associated with an increased risk of diabetes/impaired fasting glucose, but the association was significant only among boys (adjusted odds ratio 1.94, 95% CI 1.26-2.98). Alanine transaminase levels were significantly and positively related to diabetes/impaired fasting glucose risk. Overweight/obesity was significantly associated with increased risk of impaired fasting glucose/diabetes in girls, but not in boys. Moreover, the number of the above-mentioned risk factors (i.e. overweight/obesity, elevated alanine transaminase, pre-hypertension) was significantly and positively related to diabetes/impaired fasting glucose among both boys and girls.

CONCLUSIONS

Impaired fasting glucose was prevalent among urban university applicants, in particular boys and those of high socio-economic status in eastern China. Elevated levels of liver function enzyme appear to be the strongest risk factor for diabetes/impaired fasting glucose.

Association of hematological parameters with metabolic syndrome in Beijing adult population: a longitudinal study

The purposes of the study were to estimate the incidence of metabolic syndrome (MetS) and to systematically evaluate the relationship between hematological parameters and MetS in a 5-year follow-up of Beijing adult population. The longitudinal study included 3,180 adults, aged 20-65 years, who attended health check-ups in Beijing Tongren Hospital in 2007 and 2012. Multivariate logistic regression was conducted to explore the associations between hematological parameters and MetS. The 5-year cumulative incidence of MetS in this sample was 10.82 % (14.22 % for males and 7.59 % for females). Among all the hematological parameters, white blood cell count (WBC) was positively associated with MetS for 20-35-year-old (male OR 1.482, 95 % CI 1.169-2.974; female OR 1.398, 95 % CI 1.145-3.011), and 36-50-year-old (male OR 2.012, 95 % CI 1.290-4.010; female OR 3.400, 95 % CI 1.818-4.528) male and female subjects. Alanine aminotransferase (ALT) was significantly associated with the incidence of MetS for males (20-35-year-old OR 2.080, 95 % CI 1.371-3.159; 36-50-year-old OR 2.421, 95 % CI 1.335-3.412; 51-65-year-old OR 4.267, 95 % CI 1.161-6.781). Low-density lipoprotein cholesterol (LDL-C) was positively associated with MetS for 51-65-year-old (male OR 3.078, 95 % CI 2.468-5.131; female OR 2.140, 95 % CI 1.524-4.359) for male and female subjects. WBC is positively associated with MetS for young adults, while LDL-C is positively associated with MetS for elderly people. ALT is positively associated with MetS for males. Our findings provide further evidence in support of using hematological markers for early detection of individuals at risk for MetS.

Body composition and risk for metabolic alterations in female adolescents

OBJECTIVE

To study anthropometrical and body composition variables as predictors of risk for metabolic alterations and metabolic syndrome in female adolescents.

METHODS

Biochemical, clinical and corporal composition data of 100 adolescents from 14 to 17 years old, who attended public schools in Viçosa, Southeastern Brazil, were collected.

RESULTS

Regarding nutritional status, 83, 11 and 6% showed eutrophia, overweight/obesity and low weight, respectively, and 61% presented high body fat percent. Total cholesterol presented the highest percentage of inadequacy (57%), followed by high-density lipoprotein (HDL - 50%), low-density lipoprotein (LDL - 47%) and triacylglycerol (22%). Inadequacy was observed in 11, 9, 3 and 4% in relation to insulin resistance, fasting insulin, blood pressure and glycemia, respectively. The highest values of the fasting insulin and the Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) were verified at the highest quartiles of body mass index (BMI), waist perimeter, waist-to-height ratio and body fat percent. Body mass index, waist perimeter, and waist-to-height ratio were the better predictors for high levels of HOMA-IR, blood glucose and fasting insulin. Waist-to-hip ratio was associated to arterial hypertension diagnosis. All body composition variables were effective in metabolic syndrome diagnosis.

CONCLUSIONS

Waist perimeter, BMI and waist-to-height ratio showed to be good predictors for metabolic alterations in female adolescents and then should be used together for the nutritional assessment in this age range.

Association of cardiometabolic risk factors and hepatic enzymes in a national sample of Iranian children and adolescents: the CASPIAN-III study

OBJECTIVES

Elevated liver enzymes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST) may be associated with metabolic syndrome (MetS) and cardiovascular disease. We investigated the association of cardiometabolic risk factors and liver enzymes in a nationally representative sample of Iranian children and adolescents.

METHODS

The national study was conducted in the framework of the third survey of Childhood and Adolescence Surveillance and PreventIon of Adult Non-communicable Disease study. Subjects were 3948 students (1942 girls, 67.55% urban, mean age 14.7 ± 2.4 years) who were recruited by multistage random cluster sampling from 27 provincial counties in Iran. Physical examination and laboratory tests were conducted under standard protocols.

RESULTS

Participants with elevated serum ALT had higher levels of almost all cardiometabolic risk factors than other participants; this difference was not significant for fasting blood glucose, total cholesterol, and diastolic blood pressure in both sexes, as well as low-density lipoprotein cholesterol in girls. Participants with generalized and abdominal obesity, MetS, elevated blood pressure, triglycerides, and total cholesterol had increased risk for elevated ALT; this risk remained significant after adjusting for sex and age. Low high-density lipoprotein cholesterol was found as a predictor for both elevated ALT (odds ratio 2.182, 95% confidence interval 1.533-3.105) and AST (odds ratio 2.022, 95% confidence interval 1.438-2.844) even after adjusting for all potential confounders. General (B 0.158, SE 0.030) and abdominal obesity (B 0.058, SE 0.029), MetS (B 0.231, SE 0.048), and triglycerides (B 0.094, SE 0.030) were associated with ALT:AST ratio after adjusting for all potential confounders (P < 0.001).

CONCLUSIONS

We documented strong relations of elevated ALT, AST levels, and ALT:AST ratio with most cardiometabolic risk factors. This relation was independent of anthropometric indexes. Liver enzymes can be considered as a cardiometabolic risk factor from childhood, and as an additional component of the MetS.

Association between γ-glutamyl transferase and metabolic syndrome: a cross-sectional study of an adult population in Beijing

The relationship between liver enzymes and clustered components of metabolic syndrome (MetS) is explored and the predictive power of γ-glutamyl transferase (GGT) for the diagnosis of MetS in an adult population in Beijing is investigated. A total of 10,553 adults aged 20-65 years who underwent health examinations at Beijing Tongren Hospital in 2012 were enrolled in the study. Multivariate logistic regression analysis is conducted to determine the associations between the levels of various liver enzymes and clustered components of MetS. A receiver operating characteristic analysis is used to determine the optimal cut-off value of GGT for the diagnosis of MetS. A high level of GGT is found to be positively associated with clustered components of MetS in both men and women after adjusting for age, body mass index (BMI), history of alcoholic fatty liver, and the presence of taking anti-hypertensive, anti-dyslipidemic, and anti-diabetic drugs. Among all components of MetS, GGT is more predictive of triglyceride, and BMI. The area-under-the-curve values of GGT for discriminating MetS from normal metabolic status in men and women are 0.73 and 0.80, respectively. The optimal cut-off value of GGT for men is 31.50 U/L, demonstrating a sensitivity of 74.00% and specificity of 62.00%. For women, it is 19.50 U/L (sensitivity 76.00% and specificity 70.00%). GGT is therefore recommended as a useful diagnostic marker for MetS, because the test is inexpensive, highly sensitive, and frequently encountered in clinical practice.

Determinants of metabolic syndrome in Chinese schoolchildren

The objective of this study was to identify the potential risk factors of metabolic syndrome (MetS) among Chinese schoolchildren. A cross-sectional study among 624 children (357 boys and 267 girls, aged 9.6 ± 0.7 years) was conducted in Wuhan, China, from May to June 2010. MetS was defined according to the criteria proposed by De Ferranti and the International Diabetes Federation (IDF) criteria. Data on cardiorespiratory fitness (CRF), household income, parental hypertension, and children's personal information, including birth weight, preterm birth, and breast-feeding, reported by their parents were obtained. Multiple logistic regression showed that CRF (odds ratio [OR] = 0.68; 95% confidence interval [CI] = 0.60-0.77), breast-feeding (OR = 0.32; 95% CI = 0.10-0.97), and paternal hypertension (OR = 5.06; 95% CI = 1.20-21.37) were all independently associated with MetS. In conclusion, low CRF and paternal hypertension significantly increase the risk, whereas breast-feeding may reduce the risk of MetS among Chinese schoolchildren.

Liver function test changes in centrally obese youth with metabolic syndrome in a Serbian population

OBJECTIVE

The aim of this study was to investigate the association between metabolic syndrome and liver enzymes in overweight and obese adolescents and young adults.

METHODS

A total of 126 overweight and obese adolescents and young adults (age, 15-26 years), 55 (43.6%) with metabolic syndrome and 71 (56.4%) without metabolic syndrome, were studied.

RESULTS

Patients with metabolic syndrome had significantly higher alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), and alkaline phosphatase (ALP) levels compared to patients without metabolic syndrome [36.5±22.2 vs. 29.4±17.8 IU/L (P=0.043), 33.8±17.8 vs. 26.9±18.4 IU/L (P=0.002), and 84.3±32.2 vs. 75.7±29.5 IU/L (P=0.063)]. Aspartate aminotransferase (AST) levels were similar in both groups (24.1±9.8 vs. 23.3±9.0 IU/L, P=0.674). Elevated AST, ALT, GGT, and ALP levels were observed in 6, 15, 18, and 5 patients (11%, 27%, 14%, and 9%) with metabolic syndrome compared to 6, 17, 6, and 4 (8%, 24%, 8% and 5%) patients without metabolic syndrome (P=0.872, P=0.826, P<0.001, and P=0.035). In multivariate regression models adjusted for age and gender, metabolic syndrome was not a significant predictor of ALT (P=0.967), GGT (P=0.526), and ALP levels (P=0.221), but insulin resistance was a significant predictor for ALT and GGT levels (P=0.001, P=0.028).

CONCLUSION

Changes in liver function tests were observed in obese patients with metabolic syndrome, compared to patients without metabolic syndrome, especially in ALT and GGT levels. Insulin resistance is an independent pathogenic mechanism in liver function test changes regardless of metabolic syndrome in nondiabetic centrally obese youth.

Waist Circumference is a Potential Indicator of Metabolic Syndrome in Singaporean Chinese

Introduction: Metabolic Syndrome (MetS) is associated with cardiovascular morbidity and mortality. Studies proposed that waist circumference (WC) and body mass index (BMI) are good indicators of MetS. In this study, we examined and compared the predictive utility of clinical measures such as WC, blood pressure and BMI and determined the cut off points in which these measures are most reliable in identifying MetS in Singaporean Chinese. Materials and Methods: Two hundred and forty-four subjects aged between 21 and 50 years of Chinese ethnicity were recruited into the study. Sociodemographic, height, weight and blood pressure information were obtained. High-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and glucose levels were evaluated. Presence of MetS was examined according to American Heart Association (AHA)/National Heart, Lung and Blood Institute (NHLBI) guidelines. Predictive utility of BP, WC and BMI was examined using receiver operating curve and discriminant indices were determined accordingly. Results: Forty-one (16.8%) subjects were identified to have MetS. Our analysis revealed that waist circumference was most accurate in identifying MetS (area under the curve (AUC) = 0.88, 95% confidence interval (CI), 0.83 to 0.93, P 92.5 cm in males and >86.5 cm in females were found to be most sensitive and specific in discriminating MetS. Conclusion: Our finding has immediate and significant clinical implications as WC can be easily obtained. However, as the study included only Singaporean Chinese, findings cannot be generalised for other ethnic groups. Key words: Chinese, Metabolic syndrome, Waist circumference