The Triglyceride and Glucose Index Is a Predictor of Incident Nonalcoholic Fatty Liver Disease: A Population-Based Cohort Study

The usefulness of obesity and lipid-related indices to predict the presence of Non-alcoholic fatty liver disease

Background

Conicity index, body-shape index, lipid accumulation product (LAP), waist circumference (WC), triglyceride, triglyceride-glucose (TyG) index, hepatic steatosis index (HSI), waist-to-height ratio (WHtR), TyG index-related parameters (TyG-WHtR, TyG-BMI, TyG-WC), body mass index (BMI), visceral adiposity index, triglyceride to high-density lipoprotein cholesterol ratio and body roundness index have been reported as reliable markers of non-alcoholic fatty liver disease (NAFLD). However, there is debate about which of the above obesity and lipid-related indices has the best predictive performance for NAFLD risk.

Methods

This study included 6870 female and 7411 male subjects, and 15 obesity and lipid-related indices were measured and calculated. NAFLD was diagnosed by abdominal ultrasound. The area under the curve (AUC) of 15 obesity and lipid-related indices were calculated by receiver operating characteristic (ROC) analysis.

Results

Among the 15 obesity and lipid-related indices, the TyG index-related parameters had the strongest association with NAFLD. ROC analysis showed that except for ABSI, the other 14 parameters had high predictive value in identifying NAFLD, especially in female and young subjects. Most notably, TyG index-related parameters performed better than other parameters in predicting NAFLD in most populations. In the female population, the AUC of TyG-WC for predicting NAFLD was 0.9045, TyG-BMI was 0.9084, and TyG-WHtR was 0.9071. In the male population, the AUC of TyG-WC was 0.8356, TyG-BMI was 0.8428, and TyG-WHtR was 0.8372. In addition, BMI showed good NAFLD prediction performance in most subgroups (AUC>0.8).

Conclusions

Our data suggest that TyG index-related parameters, LAP, HSI, BMI, and WC appear to be good predictors of NAFLD. Of these parameters, TyG index-related parameters showed the best predictive potential.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01561-2.

The triglyceride-glucose index is a more powerful surrogate marker for predicting the prevalence and incidence of type 2 diabetes mellitus than the homeostatic model assessment of insulin resistance

AIMS

Insulin resistance is an independent risk factor for developing type 2 diabetes. Therefore, this study compared the predictability of the triglyceride-glucose (TyG) index and the homeostatic model assessment of insulin resistance (HOMA-IR) for the prevalence and incidence of type 2 diabetes.

METHODS

We analyzed data from 9730 adults aged 40-69 years at baseline and 7783 participants without diabetes who were followed up in the Korean Genome and Epidemiology Study survey. From 2001 to 2002 (baseline survey) to 2013-2014, this survey was conducted biennially (six follow-ups). The average follow-up period was 9.0 years.

RESULTS

The TyG index showed better predictability for the prevalence of type 2 diabetes than HOMA-IR (TyG index: 0.784, HOMA-IR: 0.728, p < 0.001). The area under the time-dependent receiver operating characteristic curve of the TyG index for incident type 2 diabetes was 0.640 (0.628-0.652), which was significantly higher than that of HOMA-IR [0.531 (0.521-0.541)] (p < 0.001).

CONCLUSIONS

The TyG index is superior to HOMA-IR for predicting type 2 diabetes. The TyG index could, therefore, be more useful for the early detection and prevention of type 2 diabetes.

Hepatic-Metabolite-Based Intermittent Fasting Enables a Sustained Reduction in Insulin Resistance in Type 2 Diabetes and Metabolic Syndrome

Insulin resistance is the hallmark of Type 2 Diabetes and is still an unmet medical need. Insulin resistance lies at the crossroads of non-alcoholic fatty liver disease, obesity, weight loss and exercise resistance, heart disease, stroke, depression, and brain health. Insulin resistance is purely nutrition related, with a typical molecular disease food intake pattern. The insulin resistant state is accessible by TyG as the appropriate surrogate marker, which is found to lead the personalized molecular hepatic nutrition system for highly efficient insulin resistance remission. Treating insulin resistance with a molecular nutrition-centered approach shifts the treatment paradigm of Type 2 Diabetes from management to cure. This allows remission within five months, with a high efficiency rate of 85%. With molecular intermittent fasting a very efficient treatment for prediabetes and metabolic syndrome is possible, improving the non-alcoholic fatty liver disease (NAFL) state and enabling the body to lose weight in a sustainable manner.

Association between triglyceride-glucose index and thyroid function in euthyroid adults: The Korea National Health and Nutritional Examination Survey 2015

OBJECTIVES

Low-normal thyroid function is associated with numerous metabolic risk factors including insulin resistance (IR). Triglyceride-glucose (TyG) index is a new surrogate marker of IR calculated by fasting triglyceride and glucose levels. Here, we investigated the association between thyroid function and TyG index in non-diabetic euthyroid adults.

METHODS

This cross-sectional study was based on data from the Korean National Health and Nutritional Examination Survey 2015 including 1482 individuals (741 men and 741 women). Serum thyrotropin (TSH) and free thyroxine (fT4) levels were measured.

RESULTS

After adjusting for confounders, there was an inverse relationship of TyG index with fT4 in men (β = -0.094, P = 0.009) and a positive relationship of TyG index with TSH in women (β = 0.078, P = 0.018). The lowest fT4 tertile in men (P = 0.001) and the highest TSH tertile in women (P = 0.010) exhibited increased TyG index after adjusting for confounders. The lowest fT4 tertile also showed increased homeostatic model assessment for IR (HOMA-IR) only in men (P = 0.006). Odds ratios (ORs) for the high TyG index, which was defined as the highest TyG quartile decreased in the highest and second highest tertile of fT4 in men (OR = 0.41 and OR = 0.45, respectively; P < 0.001) and increased in highest tertile of TSH in women (OR = 1.81, P = 0.031) after adjusting for confounders. The OR for high HOMA-IR defined as the highest HOMA-IR quartile was also lower in the highest and second highest fT4 tertiles in men (both OR = 0.47; P = 0.003).

CONCLUSIONS

This is the first study to suggest that TyG index is a good surrogate marker of IR in evaluating its relationship with thyroid function.

Mean and visit-to-visit variability of glycated hemoglobin, and the risk of non-alcoholic fatty liver disease

AIMS/INTRODUCTION

We aimed to determine whether mean and visit-to-visit glycated hemoglobin (HbA1c) variability independently increase the incidence of non-alcoholic fatty liver disease (NAFLD) across the diabetic continuum from normal glucose tolerance (NGT) to established diabetes.

MATERIALS AND METHODS

In a longitudinal cohort study, 21,123 participants underwent five or more annual health screening checkups. Participants were categorized into diabetes (n = 1,635), prediabetes (n = 6,650) and NGT (n = 12,838) groups. Mean, standard deviation (SD) and coefficient of variation data on HbA1c were obtained from three consecutive measurements. The associations between those data and incident NAFLD were analyzed using Cox regressions.

RESULTS

Over a median follow-up period of 57 months, 3,860 (18.3%) participants developed NAFLD. The risk of NAFLD increased continuously, with the mean HbA1c beginning at 4.9%, even in the NGT group. We found a significant association between increasing HbA1c variability and incident NAFLD (coefficient of variation, adjusted hazard ratio 1.14, 95% confidence interval 1.01-1.29; standard deviation, adjusted hazard ratio 1.19, 95% confidence interval 1.05-1.36) in the diabetes group, but not in the NGT or prediabetes group. Consistent findings were observed when NAFLD patients with a low possibility of fibrosis were excluded. The association between the coefficient of variation of HbA1c and incident NAFLD in the diabetes group was significant only in those with an increasing trend of post-baseline HbA1c (adjusted hazard ratio 1.24, 95% confidence interval 1.01-1.52).

CONCLUSIONS

Increased mean HbA1c levels elevated the risk of incident NAFLD, even with NGT. Increases in visit-to-visit variability of HbA1c independently elevated the risk of incident NAFLD, but only in the diabetes group.

An Analysis of the Potential Relationship of Triglyceride Glucose and Body Mass Index With Stroke Prognosis

Background: The inverse association between obesity and outcome in stroke patients (known as the obesity paradox) has been widely reported, yet mechanistic details explaining the paradox are limited. The triglyceride glucose (TYG) index has been proposed as a marker of insulin resistance. We sought to explore possible associations of the TYG index, body mass index (BMI), and stroke outcome. Methods: We identified 12,964 ischemic stroke patients without a history of diabetes mellitus from the China National Stroke Registry and classified patients as either low/normal weight, defined as a BMI <25 kg/m2, or overweight/obese, defined as a BMI ≥ 25 kg/m2. We calculated TYG index and based on which the patients were divided into four groups. A Cox or logistic regression model was used to evaluate the association between BMI and TYG index and its influence on stroke outcomes, including stroke recurrence all-cause mortality and poor outcome (modified Rankin Scale score of 3-6) at 12 months. Results: Among the patients, 63.3% were male, and 36.7% were female, and the mean age of the patient cohort was 64.8 years old. The median TYG index was 8.62 (interquartile range, 8.25-9.05). After adjusting for multiple potential covariates, the all-cause mortality of overweight/obese patients was significantly lower than that of the low/normal weight patients (6.17 vs. 9.32%; adjusted hazard ratio, 0.847; 95% CI 0.732-0.981). The difference in mortality in overweight/obese and low/normal weight patients with ischemic stroke was not associated with TYG index, and no association between BMI and TYG index was found. Conclusion: Overweight/obese patients with ischemic stroke have better survival than patients with low/normal weight. The association of BMI and stroke outcome is not changed by TYG index.

Triglyceride and glucose index: a useful tool for non-alcoholic liver disease assessed by liver biopsy in patients with metabolic syndrome?

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is associated with metabolic impairments, being a component of metabolic syndrome. Considering the involvement of fat accumulation and insulin resistance in NAFLD, triglyceride and glucose (TyG) index was proposed as a marker of NAFLD progression. The "gold standard" for the evaluation of liver lesions characteristic for NAFLD remains the liver biopsy. The aim of this study was to establish the links between TyG index, assessing insulin resistance, and histopathological lesions of liver samples obtained by liver biopsy in patients with metabolic syndrome.

PATIENTS, MATERIALS AND METHODS

We conducted a study over a period of three years, including 113 adult patients with metabolic syndrome in whom hepatic disorders were assessed by liver biopsy and insulin resistance was evaluated by TyG index.

RESULTS AND DISCUSSIONS

In our study, steatosis had a frequency of 92.03%, being identified 26 cases with mild steatosis, 48 with moderate steatosis and 31 with severe steatosis. Regarding non-alcoholic steatohepatitis (NASH), the frequency of this disorder in our study group was 29.2% in the subjects with liver steatosis, while liver fibrosis had a frequency of 53.09%. When we analyzed the relationships between TyG index and the presence of each type of lesion necessary for NASH diagnosis, we obtained statistically significant differences for the presence of hepatocyte ballooning (p=0.01) and a high statistically significance for the NAFLD activity score (NAS) (p<0.0001).

CONCLUSIONS

TyG index is a facile tool that can be used to identify patients at risk for advanced NAFLD lesions evaluated by liver biopsy.

Analysis of steatosis biomarkers and inflammatory profile after adding on PCSK9 inhibitor treatment in familial hypercholesterolemia subjects with nonalcoholic fatty liver disease: A single lipid center real-world experience

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) may be crucial in subjects with familial hypercholesterolemia (FH). We aimed to evaluate the effect of the inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9-i) on steatosis biomarkers such as triglyceride-glucose index (TyG) and hepatic steatosis index (HSI) and analyse the role of TG/HDL in this population before and after adding-on PCSK9-i.

METHODS AND RESULTS

In this observational study, we evaluated 26 genetically confirmed FH patients with NAFLD and an LDL-C off-target despite high-intensity statins plus ezetimibe. All patients added PCSK9-i treatment and obtained biochemical analysis and TyG and HSI evaluation at baseline and after six months of PCSK9-i. No difference of steatosis biomarkers was found after adding-on PCSK9-i therapy. In a secondary analysis, we divided the study population in two groups according to TG/HDL median value: high TG/HDL group (H-TG/HDL) and low TG/HDL group (L-TG/HDL). TyG and HSI were significantly lower in the L-TG/HDL than H-TG/HDL group (for TyG 9.05 ± 0.34 vs 9.51 ± 0.32; for HSI 38.43 ± 1.35 vs 41.35 ± 1.83, p value for both < 0.05). After six months of PCSK9-i therapy, TyG and HSI were significantly reduced in the L-TG/HDL group after PCSK9-i therapy (-7.5% and -8.4% respectively, p value for both < 0.05) and these biomarkers were lower compared to H-TG/HDL group (for TyG 8.37 ± 0.14 vs 9.19 ± 0.12; for HSI 35.19 ± 1.32 vs 39.48 ± 1.33, p value for both < 0.05).

CONCLUSION

In conclusion, PCSK9-i therapy significantly ameliorate steatosis biomarkers in FH patients with low TG/HDL; our results appear to be consistent with a beneficial role of PCSK9-i on steatosis biomarkers in FH subjects with NAFLD.

Association of Triglyceride-Glucose Index with Bone Mineral Density in Non-diabetic Koreans: KNHANES 2008-2011

The association of insulin resistance (IR), as indicated by the homeostasis model assessment of insulin resistance, with bone metabolism is yet to be clarified. We aimed to investigate the relationship of IR with bone mass by using the triglyceride-glucose (TyG) index as an alternative marker of IR. Data of 4810 non-diabetes individuals (2552 men aged ≥ 50 years and 2258 postmenopausal women) from the Korean National Health and Nutritional Examination Survey IV and V were analyzed. Bone mineral density (BMD) at the lumbar spine, femoral neck, total hip, and whole body were measured using dual-energy X-ray absorptiometry. After adjusting for confounding factors, there were inverse relationships of TyG index with femoral neck, total hip, and whole body BMD in men (β =  - 0.085, P < 0.001 at femoral neck; β =  - 0.046, P = 0.037 at total hip; β =  - 0.098, P < 0.001 at whole body). However, in women, femoral neck and whole body BMD were negatively associated with the TyG index (β =  - 0.071, P = 0.008 at femoral neck and β =  - 0.065, P = 0.005 at whole body). The highest TyG index tertile exhibited reduced femoral neck BMD in both sexes (P = 0.003 in men and P = 0.013 in women) and reduced whole body BMD in men (P < 0.001) after adjusting for confounders. When the study subjects were divided into BMI (body mass index) < 23 kg/m² and ≥ 23 kg/m² groups, the TyG index was significantly associated with femoral neck BMD only in the women with BMI < 23 kg/m² (P = 0.009). We observed a significant association between the highest TyG index tertile and low bone mass at the femoral neck in women with BMI < 23 kg/m² (P = 0.003) that was not observed in women with BMI ≥ 23 kg/m² and men. In conclusion, IR evaluated using the TyG index was inversely associated with femoral neck BMD in non-diabetic men aged ≥ 50 years and postmenopausal women. The negative influence of IR on femoral neck BMD was robust in the women with BMI < 23 kg/m². This indicates a differential effect of IR on BMD according to skeletal site, sex, and BMI.

Association of NAFLD and Insulin Resistance with Non Metastatic Bladder Cancer Patients: A Cross-Sectional Retrospective Study

Among risk factors (apart from smoking) likely involved in bladder cancer (BCa), metabolic syndrome (MS), obesity and type 2 diabetes mellitus (T2DM) have been explored with contrasting results. In spite of these studies, there is little data on the association between nonalcoholic fatty liver disease (NAFLD), its main driver, i.e., insulin resistance (IR), and BCa. Implanting a cross-sectional retrospective study we tried to investigate both NAFLD and IR prevalence in a hospital based population of BCa patients. We studied laboratory data from 204 patients with histologically confirmed non metastatic BCa and 50 subjects with no BCa, but with bladder diseases (no Ca BD). We evaluated the presence of NAFLD by the triglycerides/glucose Index (TyG Index), using a cut-off of 0.59 and by the Aspartate Aminotransferase/Alanine Aminotransferase AST/ALT ratio. IR was assessed by the same TyG Index (cut-off 4.68) and the triglycerides/High-Density Lipoprotein HDL ratio (cut-off 2.197). The diagnosis of impaired fasting glucose (IFG), condition of prediabetes, as well as that of T2DM was assessed according to canonical guidelines. The TyG Index predicted NAFLD presence in both groups (p = 0.000), but the BCa group showed a major percentage of NAFLD cases with respect to no Ca BD group (59% versus 40%). A greater proportion of IR (47%) in BCa group than in no Ca BD one (37%) was evidenced by the TyG Index with its median value significantly different (p = 0.0092). This high rate of IR in the BCa group was confirmed by the triglycerides/HDL ratio (p = 0.02). Prediabetes and T2DM were more prevalent in the BCa group than no Ca BD group (p = 0.024). In this study a consistent NAFLD presence was found in BCa patients. This is an important comorbidity factor that deserves further consideration in prospective studies. The higher prevalence of NAFLD, IR, prediabetes and T2DM in the BCa group evidences the need that these disorders should be reckoned as adjunct factors that could impact on this cancerous disease.

The Triglyceride-Glucose Index is Associated with Diabetic Retinopathy in Chinese Patients with Type 2 Diabetes: A Hospital-Based, Nested, Case-Control Study

BACKGROUND

This study aimed to investigate the association between the triglyceride-glucose (TyG) index and diabetic retinopathy (DR) in Chinese patients with type 2 diabetes.

METHODS

In this nested case-control study, all diabetic participants were registered hospitalizations during 2012-2018, including 596 with DR as cases and three matching controls per case. DR was assessed using Early Treatment Diabetic Retinopathy Study criteria. The TyG index was calculated: Ln (fasting blood glucose [mg/dL] × fasting triglycerides [mg/dL] ÷ 2). Multivariate logistic regression, a receiver-operating characteristic (ROC) curve, linear regression models, and mediation analysis were used to explore associations.

RESULTS

The TyG index was lower in DR and decreased as its severity advanced among 2,112 subjects (P=0.005). After confounders (sex, duration of diabetes, use of antidiabetic agents, heart rate, systolic blood pressure, pulse pressure, height, weight, body-mass index, and glycated hemoglobin) had been accounted for, there were significant associations between the TyG index and any-severity DR (OR 0.83, 95% CI 0.73-0.95; P=0.006), as well as vision-threatening DR (VTDR; OR 0.53, 95% CI 0.36-0.76; P=0.001). ROC analysis indicated that the TyG index showed significant discriminatory ability in any-severity DR (area under curve [AUC] 0.534, P=0.015) and VTDR (AUC 0.624, P=0.001).

CONCLUSION

The TyG index was associated with the presence and severity of DR. Our findings suggest that the TyG index may become a useful biomarker in evaluating and following the presence of DR and VTDR.

Triglyceride and glucose index and the risk of gestational diabetes mellitus: A nationwide population-based cohort study

AIMS

Pre-pregnancy insulin resistance is one of the main pathophysiologies of gestational diabetes mellitus (GDM). Triglyceride-glucose (TyG) index is a marker of insulin resistance. We aimed to evaluate the association between pre-pregnancy TyG index and GDM in primipara women.

METHODS

A total of 380,208 women who underwent a Korean national health screening exam within 2 years before their first delivery, between January 1, 2012 and December 31, 2015, were included. The TyG index was calculated as ln [triglyceride (mg/dL) × fasting plasma glucose (mg/dL)/2].

RESULTS

Among the 380,208 primipara women, 17,239 women were diagnosed with GDM (4.53%). Multivariate logistic regression analysis adjusted for risk factors showed a higher odds ratio of 1.73 for GDM (95% CI 1.65-1.81) in the highest quartile than that in the lowest quartile. A 1-SD increase in the TyG index increased the risk of GDM (31%) and GDM requiring insulin therapy (82%) in the fully adjusted model. A 1-unit increase in the TyG index significantly increased the risk of GDM and GDM requiring insulin treatment by 1.81 and 3.69 times, respectively.The impact of a high TyG index on the risk of GDM was more profound in the subjects aged ≥ 35 years, with obesity, with impaired fasting glucose, who are current smokers, and with a family history of diabetes mellitus.

CONCLUSIONS

Increased pre-pregnancy TyG index is associated with a risk of GDM. Elevation of the TyG index may be an early marker of GDM.

Association Between the Triglyceride-Glucose Index and Outcomes of Nonalcoholic Fatty Liver Disease: A Large-Scale Health Management Cohort Study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasingly becoming a major health burden. Due to the difficulty of liver biopsy, there is no reliable indicator to evaluate the outcomes of NAFLD. The triglyceride-glucose (TyG) index is a simple and convenient marker of insulin resistance for use in medical practice. Whether the TyG index is predictive of later risk of NAFLD remains unknown.

OBJECTIVE

To evaluate the relationship between TyG index with NAFLD progression and improvement during a median follow-up period of 21 months.

MATERIAL AND METHODS

A total of 11,424 subjects (9327 men) diagnosed with NAFLD were included. The TyG index was calculated as follows: ln [fasting triglycerides (mg/dL) * fasting glucose (mg/dL)/2]. Multivariable Cox regression analysis was applied to analyze the data.

RESULTS

In this study, the severity of NAFLD remained the same in 38.8% of subjects, worsened in 17.4% of subjects, and improved in 43.8% of subjects. Compared with the lowest quartile of the TyG index, the adjusted HR of NAFLD progression in the highest quartile (TyG≥9.34) was 1.448 (1.229 to 1.706), and the adjusted HR of NAFLD improvement was 0.817 (0.723 to 0.923). Subgroup analysis found that smoking increased the correlation between the TyG index and the risk of NAFLD progression, while female, vegan diet, and weight control enhanced the correlation between the TyG index and the risk of NAFLD improvement.

CONCLUSION

The TyG index may be a simple and helpful indicator for further risk appraisal of NAFLD in daily clinical practice.

Triglyceride Glucose Index and Related Parameters (Triglyceride Glucose-Body Mass Index and Triglyceride Glucose-Waist Circumference) Identify Nonalcoholic Fatty Liver and Liver Fibrosis in Individuals with Overweight/Obesity

Background: The triglyceride glucose (TyG) index has been proposed as a reliable surrogate marker for nonalcoholic fatty liver disease (NAFLD). Furthermore, NAFLD is strongly related with obesity. This study aimed to compare TyG index and its related parameters (TyG-waist circumference [WC] and TyG-body mass index [BMI]), comprising TyG and obesity markers, in predicting NAFLD and liver fibrosis in overweight/obese individuals without diabetes. Methods: This was a cross-sectional study consisting of 184 overweight/obese people (96 with and 88 without NAFLD), 30-65 years of age. TyG, TyG-BMI, and TyG-WC were computed using the established formula. Liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) were determined by transient elastography (FibroScan). Results: In correlation analyses, CAP and LSM were significantly associated with WC, BMI, TyG, TyG-BMI, and TyG-WC. Regression analyses highlighted TyG-WC as a significant predictor of NAFLD, with the highest standardized odds ratio (2.25, P < 0.001); while liver fibrosis was associated more strongly with TyG-BMI. In receiver operating characteristic (ROC) analysis, TyG-WC showed the largest area under the ROC curve (AUC) for detection of NAFLD (0.693, 95% confidence interval [CI]: 0.617-0.769). However, TyG-BMI was a better discriminator of liver fibrosis (AUC: 0.635, 95% CI: 0.554-0.714). TyG-WC value of 876 (sensitivity: 81.3%, specificity: 52.3%) and TyG-BMI value of 259 (sensitivity: 78.3%, specificity: 51.3%) were the optimal cutoff points to predict NAFLD and liver fibrosis, respectively. Conclusions: The results highlight the significant associations of TyG and its related indices with NAFLD, with TyG-WC being a better indicator. TyG-BMI and TyG-WC could reliably predict liver fibrosis in this population. These indices appear to be simple, practical, and affordable tools for screening NAFLD and liver fibrosis in clinical settings.

Relationship between triglyceride glucose index and the incidence of non-alcoholic fatty liver disease in the elderly: a retrospective cohort study in China

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of liver-related diseases but relationship between triglyceride glucose (TyG) and NAFLD in the elderly is not reported yet. In this study, we investigated the role of TyG index for predicting the incidence of NAFLD in the elderly.

DESIGN AND SETTING

This is a prospective cohort study in Henan, China, from 2011 to 2018.

PARTICIPANTS AND METHODS

In total, 46 693 elderly who participated in a routine physical examination programme from 2011 to 2018 were included in this study. TyG index was calculated as ln (fasting triglyceride (mg/dL)×fasting plasma glucose (mg/dL)/2), while NAFLD was defined as hepatic steatosis after excluding other causes based on the results of abdominal ultrasonography; Cox regression model was performed to explore the relationship between TyG index and NAFLD. Also, mediation effect was used to analyse the role of the TyG index in WHtR (waist-to-height ratio) and NAFLD.

RESULTS

During the 149 041 person-years follow-up, a total of 5660 NAFLD events occurred (3.80/100 person-years). After adjusting for potential confounding factors, quartiles 4 of TyG index significantly increased the incidence of NAFLD compared with quartile 1, the HRs and 95% CI were 1.314 (1.234 to 1.457). In addition, TyG index played a partial mediating role in the relationship between WHtR and NAFLD and indirect effect was 1.009 (1.006 to 1.011).

CONCLUSION

Higher TyG index was associated with higher risk of NAFLD in the aged, and therefore, TyG index may be a novel predictor for incidence of NAFLD. Further, regular examination and evaluation of the TyG index might be useful for controlling the occurrence of NAFLD.

Association between triglyceride glucose-body mass index and non-alcoholic fatty liver disease in the non-obese Chinese population with normal blood lipid levels: a secondary analysis based on a prospective cohort study

Background

Both triglyceride glucose-body mass index (TyG-BMI) and non-alcoholic fatty liver disease (NAFLD) are linked to insulin resistance (IR). Prospective studies linking TyG-BMI to NAFLD have been limited by short follow-up. This study investigated the longitudinal association between TyG-BMI and NAFLD occurrence in the non-obese Chinese individuals.

Methods

This study determined TyG-BMI at baseline and the incidence of NAFLD at follow-up and performed a post hoc analysis of a prospective cohort study that involved assessing the risk of NAFLD in non-obese Chinese residents from January 2010 to December 2014. The incidence of NAFLD during the 5-year follow-up was identified as the endpoint. Cox proportional hazards regression analysis was used to evaluate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the incidence of NAFLD. Receiver operating characteristic (ROC) curve analysis was conducted to estimate the predictive power of TyG-BMI and its components for NAFLD. Subgroup analysis was performed to better understand other factors that may affect the association between TyG-BMI and NAFLD to identify potential special populations.

Results

During the follow-up period, 841 (8.61%) of 9767 non-obese subjects who met the screening criteria were diagnosed with NAFLD. After confounding factors were fully adjusted for, the HR of NAFLD was 3.09 (95% CI 2.63–3.63) per standard deviation (SD) increase in TyG-BMI. Furthermore, TyG-BMI had a strong predictive value (area under ROC = 0.85; 95% CI 0.84–0.86) for the incidence of NAFLD, with a specificity of 0.73 and sensitivity of 0.82. Additionally, in the male population, each SD increase in TyG-BMI was linked to an increased risk of NAFLD (HR = 2.85, 95% CI 2.30–3.53), but the risk was higher in the female population (HR = 3.58, 95% CI 2.80–4.60). Gender and TyG-BMI interacted significantly with NAFLD incidence (P < 0.0001).

Conclusion

In the normolipidaemic and non-obese subset of the Chinese population, an increase in TyG-BMI is related to an increased incidence of NAFLD. TyG-BMI may have clinical significance in identifying groups at high risk of NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-020-01409-1.

The triglyceride-glucose index is associated with the severity of hepatic steatosis and the presence of liver fibrosis in non-alcoholic fatty liver disease: a cross-sectional study in Chinese adults

BACKGROUND

The triglyceride-glucose index (TyG) is a reliable predictor of non-alcoholic fatty liver disease (NAFLD). Its association with the severity of hepatic steatosis and liver fibrosis in NAFLD is poorly understood. This study evaluated the relationship between these factors in NAFLD.

METHODS

A total of 4784 participants who underwent ultrasonography were enrolled. Anthropometric and biochemical measurements were assessed. Participants with NAFLD were diagnosed by ultrasound. The degree of hepatic steatosis and liver stiffness was evaluated with transient elastography.

RESULTS

The TyG index was significantly correlated with the severity of hepatic steatosis and the presence of liver fibrosis in patients with NAFLD. TyG quartile values correlated with increasing prevalence of NAFLD (Q1 30.9%, Q2 53.3%, Q3 71.7%, and Q4 86.4%, P < 0.001) and with the presence of liver fibrosis (Q1 13.5%, Q2 17.6%, Q3 18.8%, and Q4 26.1%, P < 0.001). The AUROC for the TyG index to predict NAFLD was 0.761, resulting in a cut-off value of 8.7. However, the AUC value of the TyG index was 0.589 for liver fibrosis, which was insufficient to predict this condition. The adjusted odds of having hepatic steatosis or liver fibrosis were more strongly associated with TyG values compared with HOMA-IR.

CONCLUSION

The TyG index is positively related to the severity of hepatic steatosis and the presence of liver fibrosis in NAFLD. The index also performed better than HOMA-IR.