Insulin Resistance and the Risk of Diabetes and Dysglycemia in Korean General Adult Population

Ziziphus jujuba (Jujube) in Metabolic Syndrome: From Traditional Medicine to Scientific Validation

PURPOSE OF REVIEW

This review evaluates the therapeutic potential of Ziziphus jujuba and its main components in managing complications of metabolic syndrome, including diabetes, dyslipidemia, obesity, and hypertension.

RECENT FINDINGS

The reviewed studies provide evidence supporting the use of Z. jujuba and its main components (lupeol and betulinic acid) as natural treatments for complications of metabolic syndrome. These substances enhance glucose uptake through the activation of signaling pathways such as phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), reduce hepatic glucose synthesis, and increase glucose uptake by adipocytes and skeletal muscle cells. They also improve insulin sensitivity by modulating AMP-activated protein kinase (AMPK) activity and regulating insulin signaling proteins and glucose transporters. In the field of dyslipidemia, they inhibit triglyceride synthesis, lipid accumulation, and adipogenic enzymes, while influencing key signaling pathways involved in adipogenesis. Z. jujuba and its constituents demonstrate anti-adipogenic effects, inhibiting lipid accumulation and modulating adipogenic enzymes and transcription factors. They also exhibit positive effects on endothelial function and vascular health by enhancing endothelial nitric oxide synthase (eNOS) expression, NO production, and antioxidant enzyme activity. Z. jujuba, lupeol, and betulinic acid hold promise as natural treatments for complications of metabolic syndrome. They improve glucose metabolism, insulin sensitivity, and lipid profiles while exerting anti-adipogenic effects and enhancing endothelial function. However, further research is needed to elucidate the mechanisms and confirm their efficacy in clinical trials. These natural compounds offer potential as alternative therapies for metabolic disorders and contribute to the growing body of evidence supporting the use of natural medicines in their management.

The Impact of Japanese Dietary Patterns on Metabolic Dysfunction-Associated Steatotic Liver Disease and Liver Fibrosis

This study aimed to investigate the effect of Japanese dietary patterns on metabolic dysfunction-associated steatotic liver disease (MASLD) and liver fibrosis. After excluding factors affecting the diagnosis of hepatic steatosis, 727 adults were analyzed as part of the Health Promotion Project. The dietary patterns of the participants were classified into rice, vegetable, seafood, and sweet based on their daily food intake. Liver stiffness measurements and controlled attenuation parameters were performed using FibroScan. Energy and nutrient intake were calculated using the Brief-type Self-administered Diet History Questionnaire. Univariate and multivariate analyses were used to identify the risk factors for liver fibrosis within the MASLD population. The vegetable group had significantly lower liver fibrosis indicators in the MASLD population than the rice group. The multivariate analysis identified a body mass index ≥ 25 kg/m2 (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.01-1.83; p = 0.047) and HOMA-IR ≥ 1.6 (OR, 3.18; 95% CI, 1.74-5.78; p < 0.001) as risk factors for liver fibrosis, and vegetable group membership was a significant low-risk factor (OR, 0.38; 95% CI, 0.16-0.88; p = 0.023). The multivariate analysis of nutrients in low-risk foods revealed high intake of α-tocopherol (OR, 0.74; 95% CI, 0.56-0.99; p = 0.039) as a significant low-risk factor for liver fibrosis. This study suggests that a vegetable-based Japanese dietary pattern, through the antioxidant effects of α-tocopherol, may help prevent liver fibrosis in MASLD and the development of MASLD.

Association between experience of insulin resistance and long-term cardiovascular disease risk: findings from the Korean Genome and Epidemiology Study (KOGES)

PURPOSE

Although the correlation between insulin resistance (IR) and cardiovascular disease (CVD) risk is well-established, the impact of changes in IR status over time has received little attention. This study aimed to investigate the effect of IR on CVD risk in a large prospective cohort of middle-aged Korean adults.

METHODS

We assessed 3597 participants from the Korean Genome and Epidemiology Study (KoGES). Participants were categorized as having IR if their HOMA-IR was ≥2.5 at least once during the exposure period. Multivariate Cox proportional hazards regression analysis was performed to assess hazard ratios (HRs) with 95% CIs for incident CVD after adjusting for confounders.

RESULTS

Among a total of 3597 participants, 2259 did not have IR and 1138 had IR. The cumulative incidence rate of CVD in the IR group was significantly higher than that in the non-IR group (log-rank test, p = 0.015). Compared to the non-IR group, the HR and 95% CI for incident CVD in the IR group was 1.40 (1.07-1.83) in the unadjusted model. The presence of IR during the exposure period was significantly associated with a higher risk of incident CVD after adjusting for age, sex, body mass index, diabetes, hypertension, dyslipidemia, C-reactive protein, physical activity, alcohol intake, and smoking status (HR = 1.37; 95% CI: 1.01-1.84).

CONCLUSION

Individuals who have experienced IR have a consistently higher likelihood of developing CVD than those who have never had IR. More intensive efforts should be made to prevent IR in middle-aged and older adults.

Association between birth weight and insulin resistance in US adolescents: A retrospective cohort study exploring the role of concurrent body mass index

BACKGROUND AND AIMS

This study aimed to investigate the association between birth weight (BW) and abnormal HOMA-IR in US adolescents aged 12-15 years. The role of concurrent body mass index (BMI) in adolescence was also examined.

METHODS AND RESULTS

This retrospective cohort study included 3429 participants from NHANES with data in 1999-2020. HOMA-IR ≥2.3 was considered abnormal. Participants were classified as low (LBW; <2.5 kg), normal (NBW; 2.5-4.0 kg), or high (HBW; >4.0 kg) BW. Logistic regression was used to explore the association between BW and HOMA-IR. Mediation analysis was used to examine whether BMI z-score in adolescence mediated the association between BW and HOMA-IR. Compared with those in NBW, the odds ratios (95 % CI) of abnormal HOMA-IR in LBW and HBW groups were 1.26 (0.99-1.60), and 0.62 (0.47-0.83) respectively. The association between BW and abnormal HOMA-IR was consistent in all subgroups with no significant interactions. Mediation analysis showed that BW is associated with lower risk of HOMA-IR directly, but with higher risk indirectly via BMI in adolescence.

CONCLUSION

There was a negative linear relationship between BW and the prevalence of abnormal HOMA-IR in adolescents aged 12-15 independent of concurrent BMI. Children who were born with LBW but had high BMI in adolescence were of particularly higher risk of insulin resistance.

Evaluation of insulin secretion and insulin sensitivity in pregnant women: Application value of simple indices

The prevalence of gestational diabetes mellitus (GDM) is increasing annually, which poses substantial harm to the health of both mothers and children. Therefore, selection of clinically applicable and easily detectable indicators in the assessment of maternal insulin secretory function and insulin sensitivity in pregnant women undoubtedly holds great importance in evaluating the risk of GDM, guiding the choice of GDM therapy modalities, and improving the ability to provide early warning of adverse pregnancy outcomes. Compared with the classic clamp technique, many simple indices are more suited for use among pregnant women due to the low frequency of blood sampling and simple administration involved. While indices derived from fasting blood glucose and fasting insulin levels are most readily available, they are unable to provide information on the ability of insulin to manage the glucose load during pregnancy. Although the indices derived from the insulin and glucose values at each time point of the oral glucose tolerance test can provide a more comprehensive picture of the insulin sensitivity and insulin secretory function of the body, their application is constrained by the complexity of the procedure and associated high costs. Concomitantly, the findings from different studies are influenced by a variety of confounding factors, such as the gestational age during testing, race, and detection method. Furthermore, insulin secretory function and insulin sensitivity in pregnant women differ from those in non-pregnant women in that they change significantly with prolonged pregnancy; hence, there is an urgent need to develop a pregnancy-specific reference range. This article reviews the progress in the application of simple indices to help clinicians better understand their potential application in detecting GDM.

Assessment HOMA as a predictor for new onset diabetes mellitus and diabetic complications in non-diabetic adults: a KoGES prospective cohort study

BACKGROUND

Homeostasis model assessment for insulin resistance (HOMA-IR) is a biomarker for type 2 diabetes mellitus (T2DM). However, the role of HOMA-IR in the non-diabetic is unclear. This study aimed to determine whether IR measured HOMA-IR value is associated with new onset diabetes as well as vascular disease and can be used as an early predictor for diabetes and vascular diseases in non-diabetic participants.

METHODS

From a prospective community-based cohort of 10,030 individuals, 4314 individuals younger than 65 years and without diabetes were enrolled and divided into three groups by baseline HOMA-IR tertiles: low (n = 1454), moderate (n = 1414), and high (n = 1446). The primary outcome was new onset T2DM. Secondary outcomes were chronic kidney disease (CKD) and a composite of coronary artery disease, myocardial infarction, and stroke as macrovascular events.

RESULTS

The mean age was 51 years. The prevalence of hypertension and cholesterol and HbA1c were higher in the high HOMA-IR group. New onset T2DM (5.8%) and CKD (12.2%) incidence in the high HOMA-IR group was higher than that in the others. The prevalence of macrovascular events did not differ among groups. High-HOMA-IR was an independent risk factor for new onset T2DM (odds ratio 1.86 [1.17-2.96]; p = 0.01) and CKD (1.49 [1.12-1.98]; p = 0.01).

CONCLUSIONS

High HOMA-IR was an early predictor of new onset T2DM and CKD, regardless of HbA1c in non-diabetic individuals. Further research on the specific cut off value will be needed.

Triglyceride glucose index as a predictor of mortality in middle-aged and elderly patients with type 2 diabetes in the US

Despite a wealth of research linking the triglyceride glucose index (TyG index) to metabolic diseases. However, little evidence links the TyG index to all-cause or CVD mortality in middle-aged and elderly individuals with type 2 diabetes (T2D). This study analyzed data from 2998 patients with T2D who participated in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018. The TyG index and mortality in middle-aged and elderly T2D patients were investigated using Cox regression models. The nonlinear association between the TyG index and mortality can be understood with the help of a restricted cubic spline (RCS). During a median follow-up period of 82 months, 883 fatalities were observed from all causes and 265 from CVD. The TyG index was found to have a U-shaped relationship with all-cause and CVD mortality in T2D, with cutoffs of 8.95 and 9, respectively, according to the RCS. After controlling for other factors, an increase of 1 unit in the TyG index was related to an increase of 33% in all-cause mortality and 50% in CVD mortality when TyG was ≥ 8.95 and 9. When TyG < 8.95 and 9, with the change in the TyG index, the change in all-cause and CVD death was insignificant. Patients with T2D who are middle-aged or older, especially elderly patients, have higher TyG levels associated with increased mortality. In middle-aged and elderly patients with T2D, the TyG index may predict the probability of death from any cause and death from CVD.

Non-Alcoholic Fatty Liver Disease with Sarcopenia and Carotid Plaque Progression Risk in Patients with Type 2 Diabetes Mellitus

BACKGROUND

We aimed to evaluate whether non-alcoholic fatty liver disease (NAFLD) with or without sarcopenia is associated with progression of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM).

METHODS

We investigated 852 T2DM patients who underwent abdominal ultrasonography, bioelectrical impedance analysis, and carotid artery ultrasonography at baseline and repeated carotid ultrasonography after 6 to 8 years. NAFLD was confirmed by abdominal ultrasonography, and sarcopenia was defined as a sex-specific skeletal muscle mass index (SMI) value <2 standard deviations below the mean for healthy young adults. SMI was calculated by dividing the sum of appendicular skeletal mass by body weight. We investigated the association between NAFLD with or without sarcopenia and the progression of carotid atherosclerosis.

RESULTS

Of the 852 patients, 333 (39.1%) were classified as NAFLD without sarcopenia, 66 (7.7%) were classified as sarcopenia without NAFLD, and 123 (14.4%) had NAFLD with sarcopenia at baseline. After 6 to 8 years, patients with both NAFLD and sarcopenia had a higher risk of atherosclerosis progression (adjusted odds ratio, 2.20; P<0.009) than controls without NAFLD and sarcopenia. When a subgroup analysis was performed on only patients with NAFLD, female sex, absence of central obesity, and non-obesity were significant factors related to increased risk of plaque progression risk in sarcopenic patients.

CONCLUSION

NAFLD with sarcopenia was significantly associated with the progression of carotid atherosclerosis in T2DM patients.

Are HOMA-IR and HOMA-B good predictors for diabetes and pre-diabetes subtypes?

BACKGROUND

To investigate the association between the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and Homeostasis Model Assessment of Beta-cell function (HOMA-B) with the incidence of diabetes and pre-diabetes subtypes.

METHODS

A total of 3101 normoglycemic people aged 20-70 years were included in the 6-year follow-up study. Multinomial logistic regression was used to calculate the incidence possibility of isolated Impaired Fasting Glucose (iIFG), isolated Impaired Glucose Tolerance (iIGT), Combined impaired fasting glucose & impaired glucose tolerance (CGI), and Diabetes Mellitus (DM) per standard deviation (SD) increment in HOMA-IR and HOMA-B in the crude and multivariable model.

RESULTS

In the multivariate model, an increase in one SD change in HOMA-IR was associated with a 43, 42, 75, and 92% increased risk of iIFG, iIGT, CGI, and DM, respectively. There was a positive correlation between the increase in HOMA-B and the incidence of iIGT; however, after adjusting the results for metabolic syndrome components, it was inversely correlated with the incidence of iIFG [Odds Ratio = 0.86(0.75-0.99)].

CONCLUSIONS

HOMA-IR is positively correlated with diabetes and pre-diabetes subtypes' incidence, and HOMA-B is inversely correlated with the incidence of iIFG but positively correlated with iIGT incidence. However, none of these alone is a good criterion for predicting diabetes and pre-diabetes.

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.

HOMA-IR as a predictor of Health Outcomes in Patients with Metabolic Risk Factors: A Systematic Review and Meta-analysis

INTRODUCTION

There exists clinical interest in the following question: Is there an association between HOMA-IR and the risk of developing metabolic diseases?

AIMS

Assessing the association between high values of HOMA-IR with the incidence of T2DM, MACE, essential hypertension, dyslipidemia, NASH, and cancer in healthy participants and participants with a component of metabolic syndrome.

METHODS

Databases were searched by an experienced librarian to find eligible studies. Observational cohort studies enrolling healthy adults and adults with metabolic syndrome components that evaluated HOMA as a marker of IR were considered for inclusion. Eligibility assessment, data extraction and risk of bias assessment were performed independently and in duplicate. Baseline characteristics of patients, cutoff values of HOMA-IR to predict metabolic events were extracted independently and in duplicate.

RESULTS

38 studies (215,878 participants) proved eligible. A higher HOMA-IR value had a significant effect on the risk of developing T2DM (HR 1.87; CI 1.40-2.49), presenting non-fatal MACE (HR 1.46; CI 1.08-1.97) and hypertension (HR 1.35; CI 1.15-1.59). No association was found regarding cancer mortality and fatal MACE with higher HOMA-IR values, there was not enough information to carry out a meta-analysis to establish an association between higher values of HOMA with cancer incidence, dyslipidemia, and NASH.

CONCLUSIONS

High values of HOMA were associated with an increased risk of diabetes, hypertension, and non-fatal MACE; yet, not for cardiovascular or cancer mortality. More research is needed to determine the value of the HOMA index in metabolic and cardiovascular outcomes.

PROSPERO REGISTRATION NUMBER

CRD42020187645.

Development and Validation of an Insulin Resistance Predicting Model Using a Machine-Learning Approach in a Population-Based Cohort in Korea

Background: Insulin resistance is a common etiology of metabolic syndrome, but receiver operating characteristic (ROC) curve analysis shows a weak association in Koreans. Using a machine learning (ML) approach, we aimed to generate the best model for predicting insulin resistance in Korean adults aged > 40 of the Ansan/Ansung cohort using a machine learning (ML) approach. Methods: The demographic, anthropometric, biochemical, genetic, nutrient, and lifestyle variables of 8842 participants were included. The polygenetic risk scores (PRS) generated by a genome-wide association study were added to represent the genetic impact of insulin resistance. They were divided randomly into the training (n = 7037) and test (n = 1769) sets. Potentially important features were selected in the highest area under the curve (AUC) of the ROC curve from 99 features using seven different ML algorithms. The AUC target was ≥0.85 for the best prediction of insulin resistance with the lowest number of features. Results: The cutoff of insulin resistance defined with HOMA-IR was 2.31 using logistic regression before conducting ML. XGBoost and logistic regression algorithms generated the highest AUC (0.86) of the prediction models using 99 features, while the random forest algorithm generated a model with 0.82 AUC. These models showed high accuracy and k-fold values (>0.85). The prediction model containing 15 features had the highest AUC of the ROC curve in XGBoost and random forest algorithms. PRS was one of 15 features. The final prediction models for insulin resistance were generated with the same nine features in the XGBoost (AUC = 0.86), random forest (AUC = 0.84), and artificial neural network (AUC = 0.86) algorithms. The model included the fasting serum glucose, ALT, total bilirubin, HDL concentrations, waist circumference, body fat, pulse, season to enroll in the study, and gender. Conclusion: The liver function, regular pulse checking, and seasonal variation in addition to metabolic syndrome components should be considered to predict insulin resistance in Koreans aged over 40 years.

Osteocalcin is associated with triglyceride glucose index rather than HOMA-IR in men with type 2 diabetes

INTRODUCTION

The involvement of osteocalcin in the regulation of glucose tolerance in humans is controversial. We utilized a novel and practical insulin resistance surrogate, the triglyceride-glucose (TyG) index, to investigate the association between serum osteocalcin and insulin resistance in men with type 2 diabetes (T2D).

METHODS

This was a retrospective cross-sectional study that included 667 male patients suffering from T2D, with measurements of N-terminal mid-fragment of osteocalcin (N-MID), triglycerides (TG), fasting blood glucose (FBG) and C-peptide collected on the same day. We used the TyG index and HOMA-IR as surrogate measures for insulin resistance. Binary logistic regression models that adjust the sociodemographic characteristics and metabolism-related factors were used to assess the associations between osteocalcin and insulin resistance. Restricted cubic spline (RCS) analysis was used to test the potential non-linear relationship between N-MID and the risk of severe insulin resistance. Subgroup analysis evaluated the robustness of the association.

RESULTS

N-MID was correlated with the level of insulin resistance when quantified by the TyG index in unadjusted and adjusted binary logistic regression models (all p < 0.05), but the relationship was not observed when assessed by HOMA-IR (all p > 0.05). RCS model further confirmed that the association between N-MID and the severe insulin resistance measured by the TyG index was non-linear (P = 0.047). Subgroup analysis showed that the association was detected only in younger patients with lower BMI and poorer glycemic control, without hypertension or smoking.

CONCLUSIONS

Osteocalcin was inversely associated with the TyG index in men with T2D.

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.

Anthropometric features in predicting insulin resistance among non-menopausal Indonesian adult females

INTRODUCTION

The prevalence of obesity is increasing worldwide in high, low, and middle-income countries such as Indonesia. Obesity rate is higher in females in Indonesia. Obesity has important contribution in the occurrence of insulin resistance (IR) and type 2 diabetes mellitus. Several anthropometric measurements such as waist circumference (WC), body mass index (BMI), body mass (BM), total body fat percentage (Fat%) and visceral fat (VF) are related to IR. This study aimed to investigate which of those measurements could be used as a better predictor of IR in non-menopausal Indonesian adult females.

METHODS

Total of 80 non-menopausal Indonesian adult females ranging from 21 to 40 years were recruited in this study. Insulin resistance was measured by using Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) equation. Subjects with HOMA-IR index >75th percentile with cut-off 2.74 were defined as IR. Waist circumference, BMI and BM were measured, while TF and VF were measured by bioelectrical impedance analysis (BIA).

RESULTS

HOMA-IR had significant correlation with WC (r = 0.563, p < 0.001), BMI (r = 0.537, p < 0.001), BM (r = 0.515, p < 0.001), VF (r = 0.515, p < 0.001), Fat% (r = 0.490, p < 0.001). The area under curve of VF (0.809), BMI (0.807), WC (0.805), and BM (0.799) are slightly larger than and Fat% (0.766).

CONCLUSION

Insulin resistance had strong correlation with all anthropometric measurements, but the correlation was less significant with Fat%.

Association between insulin resistance and lung function trajectory over 4 years in South Korea: community-based prospective cohort

Background

Hyperglycemic conditions are associated with respiratory dysfunction. Although several studies have reported that insulin resistance (IR) is related to decreased lung function, the association between IR and change in lung function has been rarely studied. This study aimed to investigate the potential association of IR on annual change in lung function using a community-based prospective cohort in Korea.

Methods

We selected 4827 Korean participants whose serial lung functions were assessed over 4 years using 1:3 propensity score matching. Exposure was baseline IR estimated with homeostatic model assessment (HOMA-IR), and outcomes were annual changes in lung function determined by calculating the regression coefficient using least-square linear regression analysis.

Results

In the multivariate linear regression, per one unit increased log transformed HOMA-IR was associated with decline in FEV₁%-predicted (β: − 0.23, 95% CI: − 0.36 to − 0.11) and FVC %-predicted (β: − 0.20, 95% CI: − 0.33 to − 0.08), respectively. In the generalized additive model plot, HOMA-IR showed a negative linear association with annual changes in FEV₁%-predicted and FVC %-predicted. The suggested threshold of HOMA-IR for decline in lung function was 1.0 unit for annual change in FEV₁%-predicted and 2.2 unit for annual change in FVC %-predicted. Age showed statistically significant effect modification on the relationship between HOMA-IR and annual change in FEV₁%-predicted. Increased HOMA-IR was associated with the decreased annual change in FEV₁%-predicted, particularly in older people.

Conclusions

In South Korea, increased HOMA-IR was associated with decline in lung function. Since IR was related to decline in FEV₁%-predicted, particularly in older people, tailored approaches are needed in these populations. The potential pulmonary hazard of IR needs to be confirmed in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01478-7.

The insulin resistance by triglyceride glucose index and risk for dementia: population-based study

Background

Insulin resistance is suggested to have negative effects on cognition; however, results from large population studies are lacking. In this study, the potential relationships between the triglyceride glucose (TyG) index, a simple surrogate marker of insulin resistance, and dementia were evaluated using a large-scale population dataset.

Methods

This was a retrospective, observational, cohort study using data from the National Health Information Database from 2009 to 2015 and included 5,586,048 participants 40 years age or older. The TyG index was used as a measure of insulin resistance, and participants were divided into quartiles based on TyG index. The incidence of dementia was assessed using hazard ratios (HRs) estimated with Cox proportional hazard modeling.

Results

During a median follow-up of 7.21 years, dementia was diagnosed in 142,714 (2.55%) participants. Alzheimer’s disease (AD) and vascular dementia (VD) were diagnosed in 74.3% and 12.5% of the participants. Multivariate-adjusted HRs for patients in the TyG index 4th quartile were higher for dementia (HRs = 1.14; 95% confidence interval [CI] 1.12–1.16), AD (HRs = 1.12; 95% CI 1.09–1.14), and VD (HRs = 1.18; 95% CI 1.12–1.23) compared with the 1st quartile of TyG index; however, this had a small effect size (Cohen’s d = 0.10, 0.08, and 0.13, respectively). These effects were independent of age, sex, smoking status, physical activity, body mass index, systolic blood pressure, and total cholesterol.

Conclusion

In this large population study, TyG index was associated with an increased risk of dementia, including AD and VD, that was independent of traditional cardiovascular risk factors, although the effect size of the TyG index was small.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-020-00758-4.

Triglyceride Glucose-Waist Circumference Better Predicts Coronary Calcium Progression Compared with Other Indices of Insulin Resistance: A Longitudinal Observational Study

The triglyceride glucose (TyG) index, a product of triglyceride and fasting glucose, is a reliable marker for insulin resistance. We aimed to investigate the association between the TyG-related markers and coronary artery calcification (CAC) progression. We enrolled 1145 asymptomatic participants who underwent repeated CAC score measurements during routine health examinations. Homeostasis model assessment of insulin resistance (HOMA-IR), TyG index, TyG-BMI (body mass index), and TyG-WC (waist circumference) were calculated. Progression of CAC was defined as (1) incident CAC in a CAC-free population, or an (2) increase of ≥2.5 units between the baseline and final square root of the CAC scores in participants with detectable CAC. According to the quartiles of parameters, we stratified the subjects into four groups. The prevalence of progression increased with the TyG-WC quartile (15.0%, 24.1%, 31.0%, and 32.2% for each of the groups; p < 0.001). The multivariate-adjusted odds ratio (95% confidence interval) for CAC score progression was 1.66 (1.01–2.77) when the highest and lowest TyG-WC index quartiles were compared. Furthermore, the predictability of TyG-WC for CAC progression was better than the other indices in terms of the area under the curve. The TyG-WC index predicted CAC progression better than other indices and could be a potential marker of future coronary atherosclerosis.

Non-alcoholic steatohepatitis and progression of carotid atherosclerosis in patients with type 2 diabetes: a Korean cohort study

BACKGROUND

There is increasing concern regarding cardiovascular risk in individuals with non-alcoholic fatty liver disease. This study was conducted to evaluate whether hepatic steatosis with or without fibrosis is associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

METHODS

From a longitudinal cohort, we enrolled 1120 patients with type 2 diabetes who underwent repeated carotid artery ultrasonography every 1-2 years. Ultrasonographic findings at baseline and after 6-8 years were compared. Presence of hepatic steatosis was mainly assessed by abdominal ultrasonography; patients with hepatic steatosis were further evaluated for hepatic fibrosis according to fibrosis-4 index. We investigated the association between liver status and atherosclerosis progression.

RESULTS

Of 1120 patients, 636 (56.8%) were classified as having hepatic steatosis at baseline. After 6-8 years, 431 (38.5%) showed atherosclerosis progression. Hepatic steatosis was significantly associated with atherosclerosis progression (adjusted odds ratio[AOR]: 1.370, 95% CI 1.025-1.832; p < 0.05). Among patients with hepatic steatosis, only individuals with fibrosis showed significant association with atherosclerosis progression (AOR: 1.615, 95% CI 1.005-2.598; p < 0.05). The association between hepatic fibrosis and atherosclerosis progression was significant in all metabolic subgroups regardless of age, body mass index, presence of metabolic syndrome, or insulin sensitivity (all p < 0.05). Furthermore, subjects with hepatic steatosis & fibrosis and ≥ 4 components of metabolic syndrome criteria showed markedly increased risk of atherosclerosis progression (AOR: 2.430, 95% CI 1.087-5.458; p < 0.05).

CONCLUSIONS

Hepatic steatosis with fibrosis is independently associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

The effect of 1% glucose loading on metabolism in the elderly patients during remifentanil-induced anesthesia: a randomized controlled trial

Background

Previous studies showed that remifentanil-induced anesthesia can inhibit surgical stress response in non-diabetic adult patients and that low-dose glucose loading during anesthesia may attenuate fat catabolism. However, little is known about the influence of glucose loading on metabolism in elderly patients, whose condition may be influenced by decreased basal metabolism and increased insulin resistance. We hypothesized that, in elderly patients, intraoperative low glucose infusion may attenuate the catabolism of fat without causing harmful hyperglycemia during remifentanil-induced anesthesia.

Methods

Elderly, non-diabetic patients scheduled to undergo elective surgery were enrolled and randomized to receive no glucose (0G group) or low-dose glucose infusion (0.1 g/kg/hr. for 1 h followed by 0.05 g/kg/hr. for 1 h; LG group) during surgery. Glucose, adrenocorticotropic hormone (ACTH), 3-methylhistidine (3-MH), insulin, cortisol, free fatty acid (FFA), creatinine (Cr), and ketone body levels were measured pre-anesthesia, 1 h post-glucose infusion, at the end of surgery, and on the following morning.

Results

A total of 31 patients (aged 75–85) were included (0G, n = 16; LG, n = 15). ACTH levels during anesthesia decreased significantly in both groups. In the LG group, glucose levels increased significantly after glucose loading but hyperglycemia was not observed. During surgery, ketone bodies and FFA were significantly lower in the LG group than the 0G group. There were no significant differences in insulin, Cr, 3-MH, and 3-MH/Cr between the two groups.

Conclusion

Remifentanil-induced anesthesia inhibited surgical stress response in elderly patients. Intraoperative low-dose glucose infusion attenuated catabolism of fat without inducing hyperglycemia.

Trial registration

This study has been registered with the University hospital Medical Information Network Center (http://www.umin.ac.jp/english/). Trial registration number: UMIN000016189. The initial registration date: January 12th 2015.

Suppression of HDAC by sodium acetate rectifies cardiac metabolic disturbance in streptozotocin-nicotinamide-induced diabetic rats

Diabetes mellitus, particularly type 2 occurs at global epidemic proportions and leads to cardiovascular diseases. Molecular studies suggest the involvement of epigenetic alterations such as histone code modification in the progression of cardiometabolic disorders. However, short chain fatty acids (SCFAs) are recognized as epigenetic modulators by their histone deacetylase inhibitory property. It is therefore hypothesized that cardiac histone deacetylase activity increases in type II diabetes and SCFA, acetate, would inhibit histone deacetylase with accompanying restoration of glucose dysregulation, cardiac lipid deposition, and tissue damage in male Wistar rats. Twenty-four male rats (240–270 g) were allotted into four groups ( n = 6 per group) namely: vehicle-treated ( p.o.), sodium acetate-treated (200 mg/kg), diabetic, and diabetic+sodium acetate-treated groups. Diabetes was induced by intraperitoneal injection of streptozotocin 65 mg/kg after a dose of nicotinamide 110 mg/kg. The results showed that diabetic rats had, glucose dysregulation, elevated serum and cardiac triglyceride, malondialdehyde, alanine aminotransferase, histone deacetylase, serum aspartate transaminase, cardiac low density lipoprotein cholesterol (LDLc), glutathione/glutathione disulphide ratio (GSH/GSSG), reduced serum and cardiac high density lipoprotein cholesterol (HDLc), and serum GSH/GSSG. Histological analysis revealed disrupted cardiac fiber in diabetic rats. However, sodium acetate attenuated glucose dysregulation and improved serum and cardiac GSH/GSSG. Sodium acetate normalized cardiac triglyceride accumulation, malondialdehyde, serum aspartate transaminase levels and prevented cardiac tissue damage in diabetic rats. These effects were associated with suppressed histone deacetylase activity. Therefore, sodium acetate attenuated but failed to normalize glucoregulation. Nevertheless, it ameliorated oxidative stress- and lipid dysmetabolism-driven cardiovascular complications in diabetic rats by the suppression of histone deacetylase activity.

Impact statement

This study provides evidence that STZ-NA-induced diabetes mellitus is associated with cardiac triglyceride accumulation and tissue disruption with corresponding increase in cardiac HDAC activity. However, sodium acetate suppresses cardiac HDAC activity and normalizes cardiac triglyceride and tissue integrity in diabetic rats. Therefore, the study suggests that sodium acetate is beneficial for cardioprotection in diabetes mellitus.

Effects of magnitude of visceral adipose tissue reduction: Impact on insulin resistance, hyperleptinemia and cardiometabolic risk in adolescents with obesity after long-term weight-loss therapy

AIM

To investigate the association between visceral adipose tissue loss and insulin resistance and hyperleptinemia in adolescents with obesity submitted to interdisciplinary weight-loss therapy.

METHODS

A total of 172 post-pubertal adolescents (body mass index greater than the 95th percentile of the Centers for Disease Control and Prevention reference growth charts) were recruited for the study. The adolescents were assigned to long-term weight-loss therapy. Body composition, visceral and subcutaneous fat, glucose metabolism, lipid profile, hepatic enzymes and leptin concentration were measured. After the therapy, the adolescents were allocated to three different groups according to the tertile of visceral fat reduction.

RESULTS

Positive effects on body composition were observed in all analysed groups independent of visceral fat reduction. It was found that visceral fat was an independent predictor of insulin resistance in the investigated population. Obese adolescents who lost a higher proportion of visceral adipose tissue (>1.8 cm) demonstrated improved metabolic and inflammatory parameters twice as much than those who presented smaller losses. Positive correlations between visceral fat reduction and glucose metabolism, lipid profile, hepatic enzymes and homeostasis model assessment of insulin resistance index were demonstrated.

CONCLUSION

The magnitude of the reduction in visceral fat was an independent predictor of insulin resistance, hyperleptinemia and metabolic disorders related to obese adolescents.

The cut-off values of surrogate measures for insulin resistance in the Korean population according to the Korean Genome and Epidemiology Study (KOGES)

OBJECTIVE

The current methods available for determining insulin resistance are complicated; hence, they are only applicable to small-scale studies. Therefore, this study aimed to classify the characteristics of surrogate measures for insulin resistance and establish valid cut-off values for predicting the development of type 2 diabetes mellitus (DM) in Korean populations.

METHODS

This prospective study included 7,643 participants aged 40-69 years from the Ansung-Ansan cohort database (2001-2012). Four surrogate measures, namely homeostasis model assessment-insulin resistance (HOMA-IR), visceral adiposity index (VAI), lipid accumulation product (LAP), and triglycerides and glucose (TyG) index, were analyzed. We analyzed each measure using receiver operating characteristic (ROC) curve for the development of type 2 DM. The cut-off value was determined as the value with the highest Youden index score in the specificity dominant area.

RESULTS

The area under the curve (AUC) was 0.566 (95% confidence interval [CI], 0.548-0.583) for HOMA-IR, 0.622 (95% CI, 0.605-0.639) for VAI, 0.642 (95% CI, 0.625-0.658) for LAP, and 0.672 (95% CI, 0.656-0.687) for TyG index. The AUC of TyG index was significantly higher than that of HOMA-IR, VAI, and LAP (p < 0.001). The cut-off value was 2.54 (sensitivity 36.8%; specificity 73.1%; hazard ratio [HR], 1.41, 95% CI, 1.25-1.59) for HOMA-IR, 2.54 (sensitivity 50.4%; specificity 68.8%; HR, 1.75, 95% CI, 1.55-1.96) for VAI, 36.6 (sensitivity 59.2%; specificity 63.9%; HR, 1.87, 95% CI, 1.64-2.14) for LAP, and 4.69 (sensitivity 62.1%; specificity 63.1%; HR, 2.17, 95% CI, 1.92-2.45) for TyG index.

CONCLUSIONS

The TyG index was a better predictor for DM than HOMA-IR. VAI and LAP showed the modest predictability for DM. The TyG index could be a useful supplementary method for identifying individuals at risk for insulin resistance and DM development.