Triglycerides and glucose index: A useful indicator of insulin resistance

The association between the size of adipocyte-derived extracellular vesicles and fasting serum triglyceride-glucose index as proxy measures of adipose tissue insulin resistance in a rat model of early-stage obesity

Introduction

Obesity is a complex disease that predisposes individuals to cardiometabolic alterations. It leads to adipose tissue (AT) dysfunction, which triggers insulin resistance (IR). This suggests that people with obesity develop local IR first and systemic IR later. AT secretes extracellular vesicles, which may be physiopathologically associated with the development of IR. Our aim was to evaluate the effect of a high-fat diet on different parameters of adiposity in a rat model of early-stage obesity and to determine if these parameters are associated with markers of systemic IR. In addition, we sought to explore the relationship between fasting blood measures of IR (Triglycerides/High Density Lipoprotein-cholesterol [TAG/HDL-c] and Triglycerides-Glucose Index [TyG Index]) with the size of adipocyte-derived extracellular vesicles (adEV).

Methods

We used a model of diet-induced obesity for ten weeks in Wistar rats exposed to a high-fat diet. Final weight gain was analyzed by Dual X-ray absorptiometry. Visceral obesity was measured as epididymal AT weight. IR was evaluated with fasting TyG Index & TAG/HDL-c, and adEV were isolated from mature adipocytes on ceiling culture.

Results

In the high-fat diet group, glucose and triglyceride blood concentrations were higher in comparison to the control group (Log2FC, 0.5 and 1.5 times higher, respectively). The values for TyG Index and adEV size were different between the control animals and the high-fat diet group. Multiple linear regression analyses showed that adEV size can be significantly associated with the TyG Index value, when controlling for epididymal AT weight.

Conclusion

Our results show that lipid and glucose metabolism, as well as the size and zeta potential of adEV are already altered in early-stage obesity and that adEV size can be significantly associated with liver and systemic IR, estimated by TyG Index.

Impact of a retrograded starch ingredient obtained from Negro Jamapa beans (Phaseolus vulgaris L. Negro Jamapa) on glucose metabolism and oxidative stress in induced diabetic lab rats model

A retrograded starch ingredient obtained from Negro Jampa beans (Phaseolus vulgaris L. Negro Jamapa), applying a debranching process (18 U/g for 12 h) and retrogradation (2 °C for 3 days), was evaluated as a potential functional ingredient to improve glucose homeostasis in a diabetic animal model. The obtained ingredient was reduced in rapid digestible starch amount compared to its related isolated native starch (34.1 % and 53.6 %, respectively) and resistant (33.4 % and 22.3 %, respectively). Therefore, a reduced total digestibility was determined for the obtained ingredient compared to native starch (51.5 % and 79 %, respectively). As consequence, diabetic animals fed with functional ingredient replacement (30 %) showed a lower and attenuated postprandial glucose levels, reducing the hyperglycaemic condition, compared with the non-treated animals (r2 = 0.9775; p ≤ 0.05), reducing the glucose serum levels 73 % compared (17.21 vs 23.6 mmol/L, respectively). Also, significant improvement on weight gain (49.75 ± 34.1 g) compared to non-treated (18.14 ± 45.52 g), as well as lower insulin resistance index and improved oxidative stress status was determined for the treated group. These results highlight the potential of retrograded starch obtained from Negro Jamapa beans as a functional ingredient focus on the improvement of the glucose homeostasis and diabetic condition.

Obesity- and lipid-related indices as a predictor of obesity metabolic syndrome in a national cohort study

Objective

Metabolic syndrome is a common condition among middle-aged and elderly people. Recent studies have reported the association between obesity- and lipid-related indices and metabolic syndrome, but whether those conditions could predict metabolic syndrome is still inconsistent in a few longitudinal studies. In our study, we aimed to predict metabolic syndrome by obesity- and lipid-related indices in middle-aged and elderly Chinese adults.

Method

A national cohort study that consisted of 3,640 adults (≥45 years) was conducted. A total of 13 obesity- and lipid-related indices, including body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), conicity index (CI), visceral adiposity index (VAI), Chinese visceral adiposity index (CVAI), lipid accumulation product (LAP), a body shape index (ABSI), body roundness index (BRI), and triglyceride glucose index (TyG-index) and its correlation index (TyG-BMI, TyG-WC, and TyG-WHtR), were recorded. Metabolic syndrome (MetS) was defined based on the criteria of the National Cholesterol Education Program Adult Treatment Panel III (2005). Participants were categorized into two groups according to the different sex. Binary logistic regression analyses were used to evaluate the associations between the 13 obesity- and lipid-related indices and MetS. Receiver operating characteristic (ROC) curve studies were used to identify the best predictor of MetS.

Results

A total of 13 obesity- and lipid-related indices were independently associated with MetS risk, even after adjustment for age, sex, educational status, marital status, current residence, history of drinking, history of smoking, taking activities, having regular exercises, and chronic diseases. The ROC analysis revealed that the 12 obesity- and lipid-related indices included in the study were able to discriminate MetS [area under the ROC curves (AUC > 0.6, P < 0.05)] and ABSI was not able to discriminate MetS [area under the ROC curves (AUC < 0.6, P > 0.05)]. The AUC of TyG-BMI was the highest in men, and that of CVAI was the highest in women. The cutoff values for men and women were 187.919 and 86.785, respectively. The AUCs of TyG-BMI, CVAI, TyG-WC, LAP, TyG-WHtR, BMI, WC, WHtR, BRI, VAI, TyG index, CI, and ABSI were 0.755, 0.752, 0.749, 0.745, 0.735, 0.732, 0.730, 0.710, 0.710, 0.674, 0.646, 0.622, and 0.537 for men, respectively. The AUCs of CVAI, LAP, TyG-WC, TyG-WHtR, TyG-BMI, WC, WHtR, BRI, BMI, VAI, TyG-index, CI, and ABSI were 0.687, 0.674, 0.674, 0.663, 0.656, 0.654, 0.645, 0.645, 0.638, 0.632, 0.607, 0.596, and 0.543 for women, respectively. The AUC value for WHtR was equal to that for BRI in predicting MetS. The AUC value for LAP was equal to that for TyG-WC in predicting MetS for women.

Conclusion

Among middle-aged and older adults, all obesity- and lipid-related indices, except ABSI, were able to predict MetS. In addition, in men, TyG-BMI is the best indicator to indicate MetS, and in women, CVAI is considered the best hand to indicate MetS. At the same time, TyG-BMI, TyG-WC, and TyG-WHtR performed better than BMI, WC, and WHtR in predicting MetS in both men and women. Therefore, the lipid-related index outperforms the obesity-related index in predicting MetS. In addition to CVAI, LAP showed a good predictive correlation, even more closely than lipid-related factors in predicting MetS in women. It is worth noting that ABSI performed poorly, was not statistically significant in either men or women, and was not predictive of MetS.

Association of Triglyceride Glucose Index with Prevalence and Incidence of Diabetic Retinopathy in a Singaporean Population

Objective

To examine the association of triglyceride glucose (TyG) index (product of fasting triglyceride and glucose) with prevalence and incidence of diabetic retinopathy (DR) in type 2 diabetes.

Methods

1339 patients from an ongoing Singapore Study of Macro-angiopathy and Micro-Vascular Reactivity in Type 2 Diabetes (SMART2D) were included in this study. Fasting triglyceride and glucose levels were quantified and color fundus photographs were assessed for DR presence and severity. Logistic regression models were used to evaluate associations of TyG index with DR prevalence and incidence (median follow-up period = 3.2 years).

Results

Mean TyG index was higher in patients with DR than no DR (9.24±0.7 versus 9.04± 0.6, p<0.001). TyG index was significantly associated with DR prevalence (OR=1.4, CI 1.1-1.7, p=0.002) and incidence (OR=1.8, CI 1.04-2.9, p=0.03), after adjusting for confounders. In a stratified analysis, the association between TyG index and DR prevalence reached significance only in the subgroup with HbA1c levels < 7.0% (OR=2, CI 1.1-3.8, p=0.03). TyG index significantly predicted DR prevalence and incidence with area under receiver operating curve as 0.77 (CI 0.74-0.80, p <0.001) and 0.66 (CI 0.57-0.76, p value <0.01), respectively.

Conclusion

TyG index is a good predictor for DR prevalence and incidence. It can also be a secondary treatment target for patients with optimally controlled levels of HbA1c.

Triglyceride-glucose index and the incidence of stroke: A meta-analysis of cohort studies

Background

Insulin resistance (IR) is involved in the pathogenesis of atherosclerosis. As a new indicator, the triglyceride-glucose (TyG) index has greater operability for the evaluation of insulin resistance. Previous studies have shown inconsistent results in evaluating the association between the TyG index and stroke incidence in people without stroke at baseline. Therefore, this study aimed to systematically assess this association through a meta-analysis.

Methods

Cohort studies with the multivariate-adjusted hazard ratio (HR) association between the TyG index and stroke were obtained by searching the PubMed, Cochrane Library, and EMBASE databases before 16 December 2021. We pooled the adjusted HR along with 95% CI using a random-effects model. The primary outcome was stroke including ischemic and hemorrhagic stroke. We conducted subgroup analyses stratified by study design, ethnicity, characteristics of participants, weight of studies, and length of follow-up duration. Review Manager 5.3 and Stata 17 were used to perform the meta-analysis.

Results

Eight cohort studies with 5,804,215 participants were included. The results showed that participants with the highest TyG index category at baseline compared to those with the lowest TyG index category were independently associated with a higher risk of stroke (HR: 1.26, 95% CI: 1.24-1.29, I² = 0%, P < 0.001). This finding was consistent with the results of the meta-analysis with the TyG index analyzed as a continuous variable (HR per each-unit increment of the TyG index: 1.13, 95% CI 1.09-1.18, I² = 0%, P < 0.001). Subgroup analysis had no significant effects (for subgroup analysis, all P > 0.05). No significant heterogeneity was observed among the included cohort studies.

Conclusion

A higher TyG index may be independently associated with a higher risk of stroke in individuals without stroke at baseline. The aforementioned findings need to be verified by a large-scale prospective cohort study to further clarify the underlying pathophysiological mechanism between the TyG index and stroke.

Triglyceride-Glucose Index Cutoff Point Is an Accurate Marker for Predicting the Prevalence of Metabolic Syndrome in Obese Caucasian Subjects

BACKGROUND

Recently, the triglyceride-glucose (TyG) index has been suggested as a surrogate insulin resistance marker. This index could act as an early screening marker in individuals with a high risk of metabolic syndrome (MS) such as obese subjects.

AIMS

The objective of this work was to detect the cutoff point of the TyG index for the diagnosis of MS according to ATPIII criteria on obese subjects and to compare with HOMA-IR.

METHODS

We conducted a cross-sectional study in 1,494 obese subjects. Measurements of adiposity parameters, blood pressure, fasting blood glucose, insulin concentration, insulin resistance (HOMA-IR), lipid profile, C-reactive protein, adipokines, and the prevalence of MS were determined. The TyG index was calculated from the next equation: Ln (fasting triglycerides (mg/dL) × fasting glucose (mg/dL))/2.

RESULTS

A total of 1,494 subjects were recruited, 421 males (28.1%) and 1,073 females (71.8%), with an average age of 45.8 ± 15.3 years (range: 29-62). A total of 677 subjects had MS (45.5%) and 817 did not show MS (54.6%). The averages of HOMA-IR and TyG index values increased as the components of MS were aggregated, and both indexes were higher in subjects with MS. The area under the curve (AUC) of the TyG index according to ATPIII criteria showed values of 0.746 (0.721-0.771; p = 0.001). The cutoff point according to the Youden index was 4.72, with sensitivity and specificity of 87% and 88.2%, respectively. For the HOMA-IR, AUC showed values of 0.682 (0.654-0.710; p = 0.01). The cutoff point was 3.23, with sensitivity and specificity of 78% and 70.1%, respectively.

CONCLUSIONS

The TyG index is more powerful for predicting MS than HOMA-IR in Caucasian obese subjects.

Comparison between distinct insulin resistance indices in measuring the development of hypertension: The China Health and Nutrition Survey

Aim

Our aim was to identify the relationship between several surrogate insulin resistance (IR) indices based on lipid products and the development of hypertension.

Materials and methods

A total of 3,281 participants aged ≥ 18 years enrolled in the China Health and Nutrition Survey from 2009 to 2015 and who were followed up for 6 years were included in the final analysis. Logistic regression was used to analyze the association between different IR indices and incident hypertension.

Results

There were 882 (28.9%) hypertensive participants in 2015. With regard to the homeostasis model assessment of insulin resistance (HOMA-IR) based on insulin level, subjects in the highest quartile of HOMA-IR values were more likely to develop hypertension [RR = 1.58 (1.26–1.98), P < 0.001] after being adjusted by sex and age, smoke habits, alcohol consumption, community type, married status, and education years in 2009. Subjects in the highest quartile of the triglyceride-glucose index (TyG) combined with body mass index (BMI) and waist circumference (WC) had more than two times the risk of hypertension after full adjustment compared with individuals in the lowest quartile (both P < 0.001), and the trend continued when adjusted for the HOMA-IR. Compared with those in the lowest quartile of TyG-BMI values, females in the highest quartile had a higher risk of developing hypertension than males [2.82 (2.01–3.97) vs. 2.56 (1.80–3.64)] after the full adjustment, and the trend existed independent of IR. Young participants in the highest quartile of the HOMA-IR had significantly higher risks of hypertension compared with subjects in the lowest quartile [1.67 (1.31–2.14), P < 0.005], and this trend was not significant in the elderly participants.

Conclusion

The results from our large-scale study elucidate the superiority of the TyG-BMI and TyG-WC compared with the HOMA-IR in the prediction of hypertension, which may be related to lipid deposition. The sex-specific predictive value is distinct for different IR indicators.

Effect of Glucose Levels on Cardiovascular Risk

Cardiovascular diseases remain the leading cause of death and disability. The development of cardiovascular diseases is traditionally associated with various risk factors, most of which are somehow related to an unhealthy lifestyle (smoking, obesity, lack of physical activity, etc.). There are also risk factors associated with genetic predisposition, as well as the presence of concomitant diseases, especially chronic ones. One of the most striking examples is, of course, type 2 diabetes. This metabolic disorder is associated with impaired carbohydrate metabolism. The main clinical manifestation of type 2 diabetes is elevated blood glucose levels. The link between diabetes and CVD is well known, so it is logical to assume that elevated glucose levels may be important, to some extent, in the context of heart and vascular disease. In this review, we tried to summarize data on the possible role of blood glucose as a risk factor for the development of CVD.

Triglyceride glucose index is related with cardiac autonomic dysfunction in patients with metabolic syndrome

Aim    Cardiac autonomic dysfunction is encountered in approximately 25 % of patients with metabolic syndrome (MetS). 24 hr Holter-ECG based heart rate variability (HRV) and heart rate turbulence (HRT) parameters are used to evaluate cardiac autonomic function. We aimed to investigate the relationship between a novel insulin resistance marker, triglyceride glucose (TyG) index and cardiac autonomic dysfunction in patients with MetS.Material and methods    We examined a total of 400 non-diabetic subjects, 136 with MetS and 264 without MetS. All underwent TyG index calculations, and 24 hr Holter-ECG recordings for the measurement of HRV and HRT parameters.Results    HRV and HRT parameters were lower or higher in patients with MetS than in subjects without MetS, indicating cardiac autonomic dysfunction. We observed significant correlations between TyG index and measures of cardiac autonomic function. Multiple linear regression analysis showed that the TyG index was an independent predictor of almost all HRV and HRT parameters.Conclusion    This study demonstrates the independent relationship between cardiac autonomic dysfunction and the TyG index, a novel marker of insulin resistance in non-diabetic patients with MetS.

Positive Association between the Triglyceride-Glucose Index and Hyperuricemia in Chinese Adults with Hypertension: An Insight from the China H-Type Hypertension Registry Study

BACKGROUND

Previous studies have revealed the triglyceride-glucose (TyG) index is closely related to hyperuricemia in the general population. However, this relationship in hypertensive patients has not been reported. The aims of this study are to investigate the relationship of the TyG index and hyperuricemia in adult Chinese hypertension.

METHODS

The China H-type Hypertension Registration (an observational, noninterventional, and real-world study) was conducted from March 01, 2018, to August 31, 2018, in 16 communities in Wuyuan of China. The TyG index was calculated from fasting triglycerides (mg/dL) and fasting glucose (mg/dL)/2. Hyperuricemia was categorized by uric acid concentration ≥420 μmol/L (7 mg/dL).

RESULTS

Overall average TyG index of 13,060 adults with hypertension was 8.87; age was 63.81 years. The TyG index was positively correlated with serum uric acid by multiple linear regression analyses (β = 38.03; 95% CI: 34.55 to 41.51). Coincidentally, logistic analyses also demonstrated the TyG index had a positive correlation with hyperuricemia (OR = 2.04; 95% CI: 1.87 to 2.24). Strong linear associations of the TyG index with serum uric acid and hyperuricemia were confirmed by restricted cubic spline analysis. Compared with subjects in the lowest quartile (7.13 to 8.44) of the TyG index, subjects in the 2^nd-4^th quartiles had 1.25 (95% CI: 1.10 to 1.41), 1.63 (95% CI: 1.43 to 1.86), and 2.79 (95% CI: 2.41 to 3.24) times greater incident risk of developing hyperuricemia. The TyG index had significant correlations between male patients and hyperuricemia (OR = 2.01) by subgroup analysis.

CONCLUSION

Positive associations were found between the TyG index and serum uric acid and between the TyG index and hyperuricemia in adults with hypertension. This trial was registered at clinicaltrials.gov as ChiCTR1800017274.

Triglyceride Glucose Index Associated With Arterial Stiffness in Chinese Community-Dwelling Elderly

Background: The population of older adults is growing rapidly with the increasing pace of aging worldwide. The triglyceride glucose (TyG) index has been a convenient and reliable surrogate marker of insulin resistance (IR). This study aimed to determine the association between the TyG index and arterial stiffness assessed by brachial-ankle pulse wave velocity (baPWV) in Chinese older adults.

Methods: A total of 2,035 participants aged 60 years or above were enrolled. Demographic, anthropometric, and cardiovascular risk factors were collected. TyG index was calculated using ln (fasting triglycerides [mg/dL] × fasting glucose [mg/dL]/2). Arterial stiffness was measured using baPWV.

Results: The participants, with the mean [standard deviation (SD)] age of 71.32 (6.75) years, the female proportion of 39.65%, the mean (SD) baPWV of 1,998 (437) cm/s, and the mean (SD) TyG index of 8.86 (0.54), were divided into four groups according to TyG index quartiles. Age-adjusted baPWV presented an increasing trend according to TyG index quartiles. In the fully adjusted linear regression model, the baPWV increased 49 cm/s, with the 95% confidence interval (CI) from 24 to 75 cm/s, per-SD increase in the TyG index. In the fully-adjusted logistic regression model, the odds ratio (95% CI) of high baPWV (>75th percentile) was 1.32 (1.09, 1.60) for each SD increase in the TyG index. The generalized additive model analysis also confirmed the significant association of the TyG index with baPWV and high baPWV.

Conclusion: The TyG index is significantly associated with arterial stiffness assessed by baPWV in Chinese older adults.

Triglyceride-Glucose Index Linked to Hospital Mortality in Critically Ill Stroke: An Observational Multicentre Study on eICU Database

Objective: The triglyceride-glucose (TyG) index is a reliable surrogate of insulin resistance and a marker for ischemic stroke (IS) incident. Whether the TyG index predicts stroke outcome remains uncertain. This study investigated the prognostic value of the TyG index in critically ill stroke patients. Methods: This was a retrospective observational study that included stroke patients, and all data were extracted from the eICU Collaborative Research Database. The TyG index was calculated as the ln [fasting glucose level (mg/dL) × triglyceride level (mg/dL)/2]. Outcomes included the hospital and intensive care unit (ICU) death. Multivariate logistic regression was used to determine independent risk factors. The smoothing curves and forest plots were illustrated. Results: A total of 4,570 eligible subjects were enrolled. The mean level of TyG index was 9.1 ± 0.7. The hospital and ICU mortality rate were 10.3 and 5.0%, respectively. TyG index as a continuous variable was associated hospital mortality in univariate analysis (OR 1.723, 95% CI 1.524-1.948, P < 0.001), adjusted model 1 (OR 1.861, 95% CI 1637-2.116, P < 0.001), and adjusted model 2 (OR 2.543, 95% CI 1.588-4.073, P < 0.001). TyG was also associated ICU mortality in univariate analysis (OR 2.146, 95% CI 1.826-2.523, P < 0.001), adjusted model 1 (OR 2.183, 95% CI 1.847-2.580, P < 0.001), and adjusted model 2 (OR 2.672, 95% CI 1.376-5.188, P < 0.001). The smoothing curves observed a continuous linear association after adjusting all covariates both in hospital and ICU mortality. Subgroup analysis demonstrated TyG index was associated with increased risk of hospital and ICU death in critically ill IS (P < 0.05), but not in hemorrhage stroke (P > 0.05). Conclusion: The TyG index is a potential predictor for hospital and ICU mortality in critically ill stroke patients, especially in IS patients.

Predictive capacity of triglyceride-glucose (TyG) index for insulin resistance and cardiometabolic risk in children and adolescents: a systematic review

Insulin resistance (IR) in childhood plays a key role in the development of metabolic changes in adulthood, therefore, it is important to diagnose it early. We aimed to investigate studies that evaluated the TyG index for prediction of IR risk and other cardiometabolic risk factors, as well as, the proposed cutoff points in childhood and adolescence. This is a systematic review elaborated according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA). The search was performed in Lilacs, PubMed and CAPES Journal Portal, using the terms "TyG index OR triglyceride-glucose index OR triglyceride and glucose index AND children OR adolescent*". Eight articles were included in this review. All were cross-sectional studies with individuals aged ≥2 and ≤20 years old, from the United States, Korea, Mexico, Brazil, and Iran. We concluded that the TyG index was positively associated with other IR prediction methods and appears to be advantageous for predicting IR risk and other cardiometabolic risk factors in children and adolescents (review registration: PROSPERO CRD42018100726).

Triglycerides/high-density lipoprotein cholesterol is a predictor similar to the triglyceride-glucose index for the diagnosis of metabolic syndrome using International Diabetes Federation criteria of insulin resistance in obese adolescents: a cross-sectional study

Objectives Metabolic syndrome (MS) is a fatal endocrinopathy that begins with insulin resistance (IR) and causes abdominal obesity, glucose intolerance, or systemic disorders. This study was aimed to determine the cut-off values for the triglyceride (TG)/high-density lipoprotein cholesterol (TG/HDL-C) ratio, the TG glucose (TyG) index and homeostasis model assessment (HOMA-IR) for the diagnosis of MS in obese adolescents, and to compare which of the three indexes would offer a more accurate approach to diagnosis. Methods The study population comprised 1,171 obese adolescents (639 females and 532 males aged 10-16 years, Body Mass Index (BMI)>=95th percentile). Indirect measures of IR screening for MS were the TG/HDL ratio, TyG index, and HOMA-IR. The cut-off values of the TG/HDL ratio, TyG index, and HOMA-IR were obtained from receiver operation characteristic (ROC) curves. Results HOMA-IR had a significant positive correlation with the TyG index (r=0.352, p<0.001) and TG/HDL-C (r=0.291, p<.001). The TyG index and TG/HDL-C showed a strong positive correlation (r=0.901, p<0.001). The TG/HDL-C ratio showed a larger ROC Area under Curve (AUC=0.849) than HOMA-IR index (AUC=0.689), but as a predictor similar to TyG index (AUC=0.833) when screening for MS. The cut-off values for MS were as follows: TG/HDL-C ratio>2.16 (sensitivity: 88.8%; specificity: 49.7%), TyG index>8.50 (sensitivity: 85.6%; specificity: 57.0%) and HOMA-IR>2.52 (sensitivity: 83.2%; specificity: 40.4%). Conclusions Both the TyG index and TG/HDL-C ratio are better markers than HOMA-IR to determine the risk of metabolic syndrome according to IDF criteria. Besides, the TyG index and TG/HDL-C ratio have similar differentiating powers to determine this risk in obese Turkish adolescents.

Interaction Among Sex, Aging, and Epigenetic Processes Concerning Visceral Fat, Insulin Resistance, and Dyslipidaemia

The distribution of adipose tissue is influenced by gender and by age, shifting from subcutaneous to visceral depots with longevity, increasing the development of several aging-related diseases and manifestations such as obesity, metabolic syndrome, and insulin resistance. Epigenetics might have an important role in aging processes. The aim of this research was to investigate the interactions between aging and epigenetic processes and the role of visceral adipose tissue, insulin resistance, and dyslipidaemia. Two different study samples of 366 and 269 adult participants were analyzed. Anthropometric, biochemical (including the triglycerides-glucose (TyG) index), and blood pressure measurements were assessed following standardized methods. Body composition measurements by Dual-energy X-ray absorptiometry (DXA) were also performed for the second sample. Methylation data were assessed by Infinium Human Methylation BeadChip (Illumina) in peripheral white blood cells. Epigenetic age acceleration was calculated using the methods DNAmAge (AgeAcc) and GrimAge (AgeAccGrim). Age acceleration (AgeAccGrim) showed better correlations than AgeAcc with most of the measured variables (waist circumference, glucose, HOMA-IR, HDL-cholesterol, triglycerides, and TyG index) for the first sample. In the second sample, all the previous correlations were confirmed, except for HOMA-IR. In addition, many of the anthropometrical measurements assessed by DXA and C-reactive protein (CRP) were also statistically associated with AgeAccGrim. Associations separated by sex showed statistically significant correlations between AgeAccGrim and HDL-cholesterol or CRP in women, whereas, in men, the association was with visceral adipose tissue mass DXA, triglycerides and TyG index. Linear regression models (model 1 included visceral adipose tissue mass DXA and TyG index and model 2 included HDL-cholesterol and CRP) showed a significant association for men concerning visceral adipose tissue mass DXA and TyG index, while HDL-cholesterol and CRP were associated in women. Moreover, structural equation modeling showed that the TyG index was mediating the majority of the visceral adipose tissue mass action on age acceleration. Collectively, these findings showed that there are different mechanisms affecting epigenetic age acceleration depending on sex. The identified relationships between epigenetic age acceleration and disease markers will contribute to the understanding of the development of age-related diseases.

Fasting plasma glucose is a stronger predictor of diabetes than triglyceride-glucose index, triglycerides/high-density lipoprotein cholesterol, and homeostasis model assessment of insulin resistance: Tehran Lipid and Glucose Study

AIMS

To compare the impact of triglyceride-glucose index (TyG-index), the product of fasting plasma glucose (FPG) and triglycerides (TG) with FPG, 2 h post-challenge plasma glucose (2 h-PCPG), TG/high-density lipoprotein cholesterol (TG/HDL-C), and homeostasis model assessment of insulin resistance (HOMA-IR) indices for prediction of type 2 diabetes (T2D) in Iranian adults during a median follow-up of 12 years.

METHODS

Study population included 4419 (1858 men) subjects with mean age of 40.6 ± 13.2 years. Multivariable Cox proportional hazard models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for each 1-standard deviation increase in each predictor. Areas under the receiver operating characteristics curves (AUC) and 95% CIs were calculated.

RESULTS

During follow-up, 215 men and 288 women developed T2D. The multivariable HRs for FPG, 2 h-PCPG, TyG-index, HOMA-IR, HOMA2-IR, and TG/HDL-C were 2.20, 1.97, 1.71, 1.33, 1.30, and 1.35 in men and 2.13, 2.11, 1.44, 1.37, 1.32, and 1.36 in women (all P < 0.001). Among the total population, the AUC for FPG [0.752 (0.727-0.776)] was similar to 2 h-PCPG but higher than TyG-index [0.697 (0.673-0.720)], TG/HDL-C [0.644 (0.620-0.669)], HOMA-IR [0.684 (0.659-0.710)], and HOMA2-IR [0.656 (0.630-0.682)]. In men, AUC of TyG-index was higher than TG/HDL-C but did not differ with HOMA-IR indices. In women, the AUC of TyG-index was higher than HOMA2-IR and TG/HDL-C, but was similar to that of HOMA-IR.

CONCLUSIONS

FPG is a stronger predictor of T2D than the TyG-index, TG/HDL-C, and HOMA-IR indices. Although TyG-index was better than TG/HDL-C in both genders, it did not rank above HOMA-IR.

Glucomannan- and glucomannan plus spirulina-enriched pork affect liver fatty acid profile, LDL receptor expression and antioxidant status in Zucker fa/fa rats fed atherogenic diets

We evaluated the effects of glucomannan or glucomannan plus spirulina-restructured pork (RP) on liver fatty acid profile, desaturase/elongase enzyme activities and oxidative status of Zucker fa/fa rats for seven weeks. Control (C), glucomannan (G) and glucomannan/spirulina (GS)-RP; HC (cholesterol-enriched control), HG and HGS (cholesterol-enriched glucomannan and glucomannan/spirulina-RP) experimental diets were tested. Increased metabolic syndrome markers were found in C, G and GS rats. Cholesterol feeding increased liver size, fat, and cholesterol and reduced antioxidant enzyme levels and expressions. Cholesterolemia was lower in HG and HGS than in HC. GS vs. G showed higher stearic but lower oleic levels. SFA and PUFA decreased while MUFA increased by cholesterol feeding. The arachidonic/linoleic and docosahexaenoic/alpha-linolenic ratios were lower in HC, HG, and HGS vs. C, G, and GS, respectively, suggesting a delta-6-elongase-desaturase system inhibition. Moreover, cholesterol feeding, mainly in HGS, decreased low-density-lipoprotein receptor expression and the delta-5-desaturase activity and increased the delta-9-desaturase activity. In conclusion, the liver production of highly unsaturated fatty acids was limited to decrease their oxidation in presence of hypercholesterolaemia. Glucomannan or glucomannan/spirulina-RP has added new attributes to their functional properties in meat, partially arresting the negative effects induced by high-fat-high-cholesterol feeding on the liver fatty acid and antioxidant statuses.