Fasting insulin concentrations and incidence of hypertension, stroke, and coronary heart disease: a meta-analysis of prospective cohort studies

Exploring Factors Influencing Stroke Risk: Insights From a Predictive Analysis

Introduction Stroke is a serious medical condition characterized by the sudden interruption of blood flow to the brain, resulting in the death of brain cells. It is a leading cause of long-term disability and mortality worldwide. Stroke has some associated risk factors, both modifiable and non-modifiable ones. As for non-modifiable risk factors, these are age, gender (men are more vulnerable), and family history of stroke. The controllable or adjustable risk factors include hypertension (high blood pressure), diabetes, smoking, high cholesterol levels, obesity, and insulin resistance. Methods In our study, we collected data from 229 patients which were originally collected for clinical purposes and were retrospectively analyzed. These data contain features such as sex and age, the presence of ischemic heart disease (IHD) or stroke history, and different blood sugar readings. These measurements include fasting blood sugar (FBS), postprandial blood sugar (PPBS), HbA1c%, and insulin levels (fasting and postprandial). Furthermore, cholesterol was also tested, such as total cholesterol, triglycerides (TGL), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL). Surprisingly, stroke was observed in 24 of the 205 patients. This contrast permits us to be concerned with the chance of the association between stroke and insulin levels. Given the imbalanced nature of our outcome variable (stroke occurrence), the primary analytical method will be logistic regression. Results In this cross-sectional study, we investigated the association between high insulin levels (both fasting and postprandial) and the occurrence of stroke within a dataset of 229 patients. Out of the 229 included cases, 102 individuals were female (44.5%) and 127 individuals were male (55.5%). Twenty-four cases have ischemic heart disease (10.5%). Among the analyzed cases, 24 individuals have a history of stroke. The average age of the sample is approximately 57 years ± 14.87. There was no significant difference between the males and females in most of the descriptive statistics. However, females experienced significantly higher levels of postprandial glucose level and significantly lower levels of postprandial insulin. According to our predictive model, we found that an increase in fasting insulin levels was linked to a lower risk of stroke occurrence. On the other hand, increasing insulin postprandial levels and age were associated with an increased risk of stroke. Conclusion Our study identified age, fasting insulin, and postprandial insulin as key factors influencing stroke risk. Higher fasting insulin levels were associated with reduced risk, while increased postprandial insulin and age were linked to higher risk. Blood glucose, cholesterol, and triglycerides had minor effects. Notably, higher total cholesterol and triglyceride levels were slightly associated with lower stroke occurrence. Further research with larger samples is needed for validation.

Mendelian randomization study on insulin resistance and risk of hypertension and cardiovascular disease

Observational studies have suggested that insulin resistance (IR) is associated with hypertension and various cardiovascular diseases. However, the presence of a causal relationship between IR and cardiovascular disease remains unclear. Here, we applied Mendelian randomization (MR) approaches to address the causal association between genetically determined IR and the risk of cardiovascular diseases. Our primary genetic instruments comprised 53 SNPs associated with IR phenotype from a GWAS of up to 188,577 participants. Genetic association estimates for hypertension and venous thromboembolism (VTE) were extracted from UK Biobank, estimates for atrial fibrillation (AF) were extracted from the hitherto largest GWAS meta-analysis on AF, estimates for heart failure were extracted from HERMES Consortium, estimates for peripheral artery disease (PAD) and aortic aneurysm were extracted from the FinnGen Study. The main analyses were performed using the random-effects inverse-variance weighted approach, and complemented by sensitivity analyses and multivariable MR analyses. Corresponding to 55% higher fasting insulin adjusted for body mass index, 0.46 mmol/L lower high-density lipoprotein cholesterol and 0.89 mmol/L higher triglyceride, one standard deviation change in genetically predicted IR was associated with increased risk of hypertension (odds ratio (OR) 1.06, 95% CI 1.04-1.08; P = 1.91 × 10-11) and PAD (OR 1.90, 95% CI 1.43-2.54; P = 1.19 × 10-5). Suggestive evidence was obtained for an association between IR and heart failure (OR per SD change in IR: 1.19, 95% CI 1.01-1.41, P = 0.041). There was no MR evidence for an association between genetically predicted IR and atrial fibrillation, VTE, and aortic aneurysm. Results were widely consistent across all sensitivity analyses. In multivariable MR, the association between IR and PAD was attenuated after adjustment for lipids (P = 0.347) or BMI (P = 0.163). Our findings support that genetically determined IR increases the risk of hypertension and PAD.

Unraveling Adipose Tissue Dysfunction: Molecular Mechanisms, Novel Biomarkers, and Therapeutic Targets for Liver Fat Deposition

Adipose tissue (AT), once considered a mere fat storage organ, is now recognized as a dynamic and complex entity crucial for regulating human physiology, including metabolic processes, energy balance, and immune responses. It comprises mainly two types: white adipose tissue (WAT) for energy storage and brown adipose tissue (BAT) for thermogenesis, with beige adipocytes demonstrating the plasticity of these cells. WAT, beyond lipid storage, is involved in various metabolic activities, notably lipogenesis and lipolysis, critical for maintaining energy homeostasis. It also functions as an endocrine organ, secreting adipokines that influence metabolic, inflammatory, and immune processes. However, dysfunction in WAT, especially related to obesity, leads to metabolic disturbances, including the inability to properly store excess lipids, resulting in ectopic fat deposition in organs like the liver, contributing to non-alcoholic fatty liver disease (NAFLD). This narrative review delves into the multifaceted roles of WAT, its composition, metabolic functions, and the pathophysiology of WAT dysfunction. It also explores diagnostic approaches for adipose-related disorders, emphasizing the importance of accurately assessing AT distribution and understanding the complex relationships between fat compartments and metabolic health. Furthermore, it discusses various therapeutic strategies, including innovative therapeutics like adipose-derived mesenchymal stem cells (ADMSCs)-based treatments and gene therapy, highlighting the potential of precision medicine in targeting obesity and its associated complications.

Magnitude and time course of insulin resistance accumulation with the risk of cardiovascular disease: an 11-years cohort study

BACKGROUND

The risk of cardiovascular disease (CVD) depended on the magnitude and exposure duration of insulin resistance (IR). This study aimed to investigate the associations of cumulative metabolic score for IR (cumMETS-IR) with incident CVD, and to further explore the modulated effects of time course of METS-IR accumulation.

METHODS

We enrolled 47,270 participants without CVD and underwent three examinations during 2006-2010 from the Kailuan study. CumMETS-IR from 2006 to 2010 were calculated as the mean values of METS-IR between consecutive examinations multiplying by time intervals between visits. Time course of METS-IR accumulation was calculated as the slope of METS-IR versus time. Hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD risk were calculated with multivariable-adjusted Cox regressions.

RESULTS

During a median follow-up of 10.99 years, we identified 3184 cases of incident CVD. The risk of incident CVD increased with increasing cumMETS-IR (HR, 1.77; 95% CI 1.58-1.98 for the Q4 versus Q1 group), exposure duration (HR, 1.60; 95% CI 1.45-1.77 for 6 years versus 0 years), and cumulative burden (HR, 1.49; 95% CI 1.37-1.61 for burden ≥ 0 versus < 0). A positive slope was associated with 14% higher risk of CVD (HR, 1.14; 95% CI 1.07-1.22). When combining cumMETS-IR and slope, those with cumMETS-IR ≥ median (142.78) and slope ≥ 0 had the highest risk of CVD (HR,1.38; 95% CI 1.25-1.53).

CONCLUSIONS

The risk of CVD increased with elevated cumMETS-IR and an increasing trend over time, emphasizing the importance of maintaining optimal METS-IR levels across life span.

A synthesis of pathways linking diet, metabolic risk and cardiovascular disease: a framework to guide further research and approaches to evidence-based practice

Cardiovascular disease (CVD) is the most common non-communicable disease occurring globally. Although previous literature has provided useful insights into the important role that diet plays in CVD prevention and treatment, understanding the causal role of diets is a difficult task considering inherent and introduced weaknesses of observational (e.g. not properly addressing confounders and mediators) and experimental research designs (e.g. not appropriate or well designed). In this narrative review, we organised current evidence linking diet, as well as conventional and emerging physiological risk factors, with CVD risk, incidence and mortality in a series of diagrams. The diagrams presented can aid causal inference studies as they provide a visual representation of the types of studies underlying the associations between potential risk markers/factors for CVD. This may facilitate the selection of variables to be considered and the creation of analytical models. Evidence depicted in the diagrams was systematically collected from studies included in the British Nutrition Task Force report on diet and CVD and database searches, including Medline and Embase. Although several markers and disorders linked to conventional and emerging risk factors for CVD were identified, the causal link between many remains unknown. There is a need to address the multifactorial nature of CVD and the complex interplay between conventional and emerging risk factors with natural and built environments, while bringing the life course into the spotlight.

Triglyceride-glucose index is associated with hypertension incidence up to 13 years of follow-up in mexican adults

The triglyceride-glucose index (TyG index) is an indicator of insulin resistance that has been studied recently. The relationship between insulin resistance and the risk of hypertension has been documented previously. However, there is limited knowledge regarding the association of the TyG index with hypertension incidence. This study aimed to evaluate the association of the TyG index with changes in blood pressure (BP) and hypertension incidence in Mexican adults. This analysis was performed using the Health Workers Cohort Study data. The TyG index was estimated as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2] and divided into categories defined by tertiles. The analysis was conducted using fixed-effects linear regression models (n = 1,545) and Cox proportional hazards regression models (n = 1,113), adjusting for potential confounding variables. The incidence rates (95% CI) for the low, medium, and high categories of the TyG index were 22.1 (17.8, 27.5), 35.8 (30.1, 42.7), and 49.4 (42.1, 57.9), respectively. An increase in the levels of systolic blood pressure (SBP) and diastolic blood pressure (DBP) was observed when changing from a low to a medium (DBP: β 2.55 mmHg, 95% CI 0.81, 4.29) and from a low to a high category of the TyG index (SBP: β 3.10 mmHg, 95% CI 1.16, 5.04; DBP: β 4.91 mmHg, 95% CI 2.88, 6.94). Furthermore, participants within the top category of the TyG index had a 56% higher risk of hypertension than those in the bottom category (HR = 1.56; 95% CI 1.18, 2.08). These results support the hypothesis that the TyG index is associated with high blood pressure in Mexican adults.

Triglyceride glucose-body mass index and hypertension risk in iranian adults: a population-based study

BACKGROUND

Insulin resistance (IR) and obesity are risk factors for hypertension; triglyceride-glucose (TyG) is known as a surrogate for IR. The present study investigated the association between the triglyceride-glucose body mass index (TyG-BMI) index and the risk of hypertension in Iranian adults.

METHODS

This study was conducted on a sample of 8,610 participants from the baseline phase of the Ravansar non- communicable diseases (RaNCD) in Iran. A logistic regression model was used to evaluate the relationship between TyG-BMI and hypertension. Receiver operating characteristic (ROC) curve analysis was conducted to estimate the predictive power of TyG-BMI for hypertension.

RESULTS

A total of 4176 men and 4434 women with an average age of 46.74 years were examined. The anthropometric indices were significantly higher in hypertensive than normotensive subjects (P < 0.001). The level of physical activity was significantly higher in the bottom quartiles (P < 0.001). The odds of hypertension in the highest quartile and 3.10 (95% CI: 2.28, 4.16) times significantly higher than the bottom quartile of the TyG-BMI index. The discriminating ability of TyG-BMI to predict blood pressure was 61% (AUC: 0.61; 95% CI: 0.57, 0.63), and higher than BMI and TyG.

CONCLUSION

The TyG-BMI index is associated with an increase in the odds of hypertension. Therefore, the TyG-BMI index can be a new clinical index for early diagnosis of hypertension. Lifestyle modifications such as weight control through physical activity and a healthy diet can help improve IR and prevent hypertension.

Sex-specific responses in glucose-insulin homeostasis and lipoprotein-lipid components after high-dose supplementation with marine n-3 PUFAs in abdominal obesity: a randomized double-blind crossover study

Background

Clinical studies on effects of marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the plant-derived omega-6 (n-6) PUFA linoleic acid (LA) on lipoprotein-lipid components and glucose-insulin homeostasis have shown conflicting results, which may partly be explained by differential responses in females and males. However, we have lacked data on sexual dimorphism in the response of cardiometabolic risk markers following increased consumption of n-3 or n-6 PUFAs.

Objective

To explore sex-specific responses after n-3 (EPA + DHA) or n-6 (LA) PUFA supplementation on circulating lipoprotein subfractions, standard lipids, apolipoproteins, fatty acids in red blood cell membranes, and markers of glycemic control/insulin sensitivity among people with abdominal obesity.

Methods

This was a randomized double-blind crossover study with two 7-week intervention periods separated by a 9-week washout phase. Females (n = 16) were supplemented with 3 g/d of EPA + DHA (fish oil) or 15 g/d of LA (safflower oil), while males (n = 23) received a dose of 4 g/d of EPA + DHA or 20 g/d of LA. In fasting blood samples, we measured lipoprotein particle subclasses, standard lipids, apolipoproteins, fatty acid profiles, and markers of glycemic control/insulin sensitivity.

Results

The between-sex difference in relative change scores was significant after n-3 for total high-density lipoproteins (females/males: -11%*/-3.3%, p = 0.036; *: significant within-sex change), high-density lipoprotein particle size (+2.1%*/-0.1%, p = 0.045), and arachidonic acid (-8.3%*/-12%*, p = 0.012), and after n-6 for total (+37%*/+2.1%, p = 0.041) and small very-low-density lipoproteins (+97%*/+14%, p = 0.021), and lipoprotein (a) (-16%*/+0.1%, p = 0.028). Circulating markers of glucose-insulin homeostasis differed significantly after n-3 for glucose (females/males: -2.1%/+3.9%*, p = 0.029), insulin (-31%*/+16%, p < 0.001), insulin C-peptide (-12%*/+13%*, p = 0.001), homeostasis model assessment of insulin resistance index 2 (-12%*/+14%*, p = 0.001) and insulin sensitivity index 2 (+14%*/-12%*, p = 0.001), and quantitative insulin sensitivity check index (+4.9%*/-3.4%*, p < 0.001).

Conclusion

We found sex-specific responses after high-dose n-3 (but not n-6) supplementation in circulating markers of glycemic control/insulin sensitivity, which improved in females but worsened in males. This may partly be related to the sex differences we observed in several components of the lipoprotein-lipid profile following the n-3 intervention.

Clinical trial registration

https://clinicaltrials.gov/, identifier [NCT02647333].

Hyperinsulinemia Impaired Coronary Collateral Circulation in Patients with Chronic Total Coronary Occlusion

Background and Objectives

Hyperinsulinemia impaired cardiovascular system and endothelial function in the population. The purpose of this study was to explore the relationship between hyperinsulinemia and coronary collateral circulation in patients with chronic total coronary occlusion.

Methods

Patients with stable angina and at least one total coronary occlusion were enrolled in this study. Collateral grade was determined according to Rentrop's classification. Patients were divided into a good coronary collateral circulation (CCC) group (grade 2 or 3 collateral vessels, n = 223) and a poor CCC group (grade 0 or 1 collateral vessels, n = 115). Fasting insulin level (FINS) and fasting glucose level (FBS) were measured. Endothelial function evaluated by flow-mediated dilation (FMD).

Results

Serum FINS level was significantly increased in the poor CCC group (P < 0.01). Patients in the poor CCC group had higher levels of FBS, HbA1C, and homeostasis model assessment for insulin resistance (HOMA-IR) than patients in the good CCC group. The poor CCC group also had lower levels of FMD, lower LVEF and higher syntax scores than the good CCC group. Hyperinsulinemia (T3, FINS ≥15.22 μIU/mL) increased OR for the incidence of the poor CCC group (OR 2.419, 95% CI 1.780-3.287) in multivariate analysis. Multivariate logistic regression also revealed that diabetes, HbA1c, HOMA-IR, HDL-C and Syntax score were independent predictors of poor CCC (all P < 0.05).

Conclusion

Hyperinsulinemia is a valuable predictor of poor collateral formation in patients with chronic total coronary occlusion.

Comparison of six surrogate insulin resistance indexes for predicting the risk of incident stroke: The Rural Chinese Cohort Study

BACKGROUND AND PURPOSE

Some cheap and easily used operated indexes of insulin resistance (IR) were currently available. We aimed to evaluate the association of six surrogate indexes of IR with incident stroke and to compare their predictive capacity.

METHODS

We analysed data from 14,595 eligible study participants from the Rural Chinese Cohort Study. Modified Poisson regression models were used to estimate relative risks (RRs) and 95% confidence intervals (95% CIs) of incident stroke associated with the visceral adiposity index (VAI), the Chinese visceral adiposity index (CVAI), lipid accumulation product (LAP), triglyceride-glucose (TyG), TyG-body mass index, and TyG-waist circumference. The receiver operator characteristic curve was used to compare the ability of the abovementioned IR indexes to predict stroke.

RESULTS

During a median follow-up of 6 years, 786 newly diagnosed stroke cases were identified. The levels of six surrogate indexes of IR were all significantly higher in the stroke population than in the non-stroke population (p < 0.001). Compared with quartile 1, the multivariable adjusted RRs (95% CIs) of incident stroke for quartile 4 were 2.01 (1.47-2.76), 1.62 (1.28, 2.04), 1.64 (1.28-2.09), and 1.92 (1.50-2.45) for CVAI, VAI, LAP, and TyG, respectively. Significant dose-response associations were also found between surrogate IR indexes and risk of stroke. The area under the curves|areas under the curves for CVAI (0.674) was significantly greater than for other indexes (TyG-WC:0.622, TyG:0.614, LAP:0.606, TyG-BMI:0.598, and VAI:0.577) (p < 0.001).

CONCLUSIONS

Six surrogate indexes of IR were independently associated with incident stroke. The CVAI may be the most suitable index for stroke prediction.

Time course of the triglyceride glucose index accumulation with the risk of cardiovascular disease and all-cause mortality

Background

Future risk of cardiovascular disease (CVD) and mortality is associated with cumulative amount TyG index (cumTyG) exposure, while whether time course of TyG accumulation modulates the risk remains unclear. This study sought to examine the associations of cumTyG index accumulation time course with the risk of CVD and all-cause mortality.

Methods

We enrolled 51,734 participants free of CVD and underwent three examinations at year 2006, 2008, and 2010. CumTyG from baseline to the third examination was calculated. Time course of cumTyG accumulation was calculated as the slope of TyG versus time from 2006 to 2010, or as splinting the overall TyG index accumulation into early (cumTyG_{06 − 08}) and late accumulation (cumTyG_{08 − 10}). Participants were categorized by the combination of cumTyG < or ≥ median (34.44 × years) and a negative or positive TyG slope.

Results

During a median follow-up of 9.04 years, we identified 3,602 incident CVD cases and 3,165 deaths. The risk of CVD and all-cause mortality increased with decreased TyG slope, the corresponding adjusted hazard ratio (aHR) with 95% confidence interval (CI) was 1.11 (1.04–1.19) and 1.18 (1.10–1.26) for patients with a negative TyG slope, respectively. Consistently, a later accumulation of TyG index was not associated with the risk of CVD and all-cause mortality after adjustment for an early accumulation. When considering the combination of cumTyG index and time course, participants with a cumTyG ≥ median and a negative TyG slope had elevated risk of CVD (aHR, 1.37; 95% CI, 1.24–1.51) and all-cause mortality (aHR, 1.28; 95% CI, 1.15–1.43). Additionally, the association was more prominent in young adults.

Conclusion

Early TyG index accumulation resulted in a greater risk of CVD and all-cause mortality than later TyG later accumulation with the same overall cumulative exposure, emphasizing the importance of optimal TyG index control earlier in life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01617-2.

Proposal for standardizing normal insulin ranges in Brazilian patients and a new classification of metabolic syndrome

Background

Insulin resistance and/or hyperinsulinemia are closely linked to adiposity, metabolic syndrome (MetS) and prolonged inflammatory processes.

Methods

We retrospectively analyzed 1,018 adult individuals with a mean age of 46 years (74% male) and classified them as: Metabolically normal: without any of the five criteria of the International Diabetes Federation (IDF) used for the diagnosis of MetS, plus normal fasting insulin (Men < 8 mU/L, Women < 10 mU/L); Level 1 MetS: with one or two IDF criteria, plus hyperinsulinemia (Men: ≥ 8 mU/L), and Women: ≥ 10 mU/L); Level 2 MetS: with three or more IDF criteria, plus hyperinsulinemia.

Results

The mean values for fasting insulinemia in metabolically normal individuals was 4.6 ± 1.8 mU/L and 5.6 ± 2.3 mU/L, while their means for the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were 1.0 and 1.2 for men and women, respectively. In addition, the mean values for insulin (and HOMA-IR) for individuals with two normal anthropometric parameters (body mass index and waist girth), or two normal anthropometric parameters plus no IDF criteria, were similar to the metabolically normal group. Based on the obtained mean + 2 SD, we established the following insulin (and HOMA-IR) values as diagnostic cut-offs for hyperinsulinemia: Men: ≥ 8 mU/L (≥ 1.5), and Women: ≥ 10 mU/L (≥ 2.0). The mean serum insulin was significantly higher for individuals with Level 1 MetS (approx. 9 mU/L for both genders) compared with metabolically normal individuals, as was the prevalence of hepatic steatosis, which was more evident in men. Thus, the presence of one or two abnormal IDF criteria, combined with hyperinsulinemia and/or raised HOMA-IR, suggests the presence of MetS and insulin resistance. Patients of both genders with Level 2 MetS had higher serum insulin and/or HOMA-IR values than Level 1, as well as a higher prevalence of hypertension and hepatic steatosis, being more pronounced among men. The process was progressive and proportional to the degree of hyperinsulinemia.

Conclusion

It is proposed that intervention against MetS progression should be started in individuals with Level 1 MetS, rather than waiting for more criteria for diagnostic confirmation, which this should help to reduce the occurrence of known complications such as type 2 diabetes, atherosclerosis, hypertension, and chronic kidney disease, among others.

The potential of DNA methylation as a biomarker for obesity and smoking

DNA methylation is an epigenetic modification that has consistently been shown to be linked with a variety of human traits and diseases. Because DNA methylation is dynamic and potentially reversible in nature and can reflect environmental exposures and predict the onset of diseases, it has piqued interest as a potential disease biomarker. DNA methylation patterns are more stable than transcriptomic or proteomic patterns, and they are relatively easy to measure to track exposure to different environments and risk factors. Importantly, technologies for DNA methylation quantification have become increasingly cost effective-accelerating new research in the field-and have enabled the development of novel DNA methylation biomarkers. Quite a few DNA methylation-based predictors for a number of traits and diseases already exist. Such predictors show potential for being more accurate than self-reported or measured phenotypes (such as smoking behavior and body mass index) and may even hold potential for applications in clinics. In this review, we will first discuss the advantages and challenges of DNA methylation biomarkers in general. We will then review the current state and future potential of DNA methylation biomarkers in two human traits that show rather consistent alterations in methylome-obesity and smoking. Lastly, we will briefly speculate about the future prospects of DNA methylation biomarkers, and possible ways to achieve them.

Distinct triglyceride-glucose trajectories are associated with different risks of incident cardiovascular disease in normal-weight adults

BACKGROUND

Long-term patterns of the triglyceride-glucose index (TyG index) and their effects on cardiovascular disease (CVD) among normal-weight adults are poorly characterized. This study aimed to identify TyG index trajectories in normal-weight adults and to determine their association with the risk of incident CVD.

METHODS

This study included 40,473 normal-weight participants who were free of stroke and myocardial infarction prior to or in 2012. The TyG index was calculated as ln (fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2), and the TyG index trajectories during 2006-2012 were identified by latent mixture modeling.

RESULTS

We identified five distinct TyG index trajectories according to TyG index range and changing pattern over time: low-stable (n = 9,806; mean TyG index 7.84-7.93), moderate-stable (n = 22,066; mean TyG index 8.43-8.52), high-decreasing (n = 1,469; mean TyG index 9.83-8.75), moderate-increasing (n = 5,842; mean TyG index 8.98-9.26), and high-stable (n = 1,290; mean TyG index 9.91-10.07). During 6.74 years of follow-up, we documented 1,577 incident CVD events. Compared with the low-stable pattern, the highest risk of CVD was observed in the high-stable pattern (hazard ratio [HR], 2.24; 95% confidence interval [CI]: 1.73-2.90), followed by the moderate-increasing pattern (HR, 1.70; 95% CI, 1.43-2.04), the high-decreasing pattern (HR, 1.45; 95% CI, 1.11-1.89), and the moderate-stable pattern (HR, 1.25; 95% CI, 1.08-1.44). Similar results were also observed for stroke and myocardial infarction.

CONCLUSIONS

Distinct TyG index trajectories were significantly associated differently subsequent risk of CVD in normal-weight individuals. These observations suggested that long-term trajectories of TyG index may be useful for predicting CVD among normal-weight adults.

Hiding unhealthy heart outcomes in a low-fat diet trial: the Women's Health Initiative Randomized Controlled Dietary Modification Trial finds that postmenopausal women with established coronary heart disease were at increased risk of an adverse outcome if they consumed a low-fat 'heart-healthy' diet

The Women's Health Initiative Randomized Controlled Dietary Modification Trial (WHIRCDMT) was designed to test whether the US Department of Agriculture's 1977 Dietary Guidelines for Americans protects against coronary heart disease (CHD) and other chronic diseases. The only significant finding in the original 2006 WHIRCDMT publication was that postmenopausal women with CHD randomised to a low-fat 'heart-healthy' diet in 1993 were at 26% greater risk of developing additional CHD events compared with women with CHD eating the control diet. A 2017 WHIRCDMT publication includes data for an additional 5 years of follow-up. It finds that CHD risk in this subgroup of postmenopausal women had increased further to 47%-61%. The authors present three post-hoc rationalisations to explain why this finding is 'inadmissible': (1) only women in this subgroup were less likely to adhere to the prescribed dietary intervention; (2) their failure to follow the intervention diet increased their CHD risk; and (3) only these women were more likely to not have received cholesterol-lowering drugs. These rationalisations appear spurious. Rather these findings are better explained as a direct consequence of postmenopausal women with features of insulin resistance (IR) eating a low-fat high-carbohydrate diet for 13 years. All the worst clinical features of IR, including type 2 diabetes mellitus (T2DM) in some, can be 'reversed' by the prescription of a high-fat low-carbohydrate diet. The Women's Health Study has recently reported that T2DM (10.71-fold increased risk) and other markers of IR including metabolic syndrome (6.09-fold increased risk) were the most powerful predictors of future CHD development in women; blood low-density lipoprotein-cholesterol concentration was a poor predictor (1.38-fold increased risk). These studies challenge the prescription of the low-fat high-carbohydrate heart-healthy diet, at least in postmenopausal women with IR, especially T2DM. According to the medical principle of 'first do no harm', this practice is now shown to be not evidence-based, making it scientifically unjustifiable, perhaps unethical.

Change in triglyceride-glucose index predicts the risk of cardiovascular disease in the general population: a prospective cohort study

BACKGROUND

Previous studies has shown a significant relationship between baseline triglyceride-glucose (TyG) index and subsequent cardiovascular disease (CVD). However, the effect of longitudinal changes in TyG index on the risk of CVD remains uncertain. This study aimed to investigate the association between change in TyG index and the risk of CVD in the general population.

METHODS

The current study included 62,443 Chinese population who were free of CVD. The TyG index was calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2], and change in TyG index was defined as the difference between the TyG index in 2010 and that in 2006. Multivariable-adjusted Cox proportional hazard models and restricted cubic spline analysis were used to examine the association between change in TyG index and the risk of CVD.

RESULTS

During a median follow-up of 7.01 years, 2530 (4.05%) incident CVD occurred, including 2018 (3.23%) incident stroke and 545 (0.87%) incident myocardial infarction (MI). The risk of developing CVD increased with the quartile of change in TyG index, after adjustment for multiple potential confounders, the hazard ratios for the Q4 group versus the Q1 group were 1.37 (95% confidence interval [CI], 1.21-1.54) for the overall CVD, 1.38 (95% CI, 1.19-1.60) for stroke, and 1.36 (95% CI, 1.05-1.76) for MI. Restricted cubic spline analysis also showed a cumulative increase in the risk of CVD with increases in the magnitude of change in TyG index. The addition of change in TyG index to a baseline risk model for CVD improved the C-statistics (P = 0.0097), integrated discrimination improvement value (P < 0.0001), and category-free net reclassification improvement value (P < 0.0001). Similar results were observed for stroke and MI.

CONCLUSIONS

Substantial changes in TyG index independently predict the risk of CVD in the general population. Monitoring long-term changes in TyG may assist with in the early identification of individuals at high risk of CVD.

Elevated triglyceride-glucose index predicts risk of incident ischaemic stroke: The Rural Chinese cohort study

AIM

As the association between insulin resistance and ischaemic stroke is conflicting, our study aimed to examine the association between triglyceride-glucose (TyG), a surrogate marker of insulin resistance, and incident ischaemic stroke, and also to further assess the potential effect of modification by several known risk factors of stroke.

METHODS

The Rural Chinese Cohort Study enrolled 11,777 participants, aged ≥40 years, who were free of stroke and cardiovascular disease at baseline during 2007-2008, and who were then followed during 2013-2014. TyG was determined using the following formula: Ln[fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. The relative risk (RR) and 95% confidence interval (CI) of incident ischaemic stroke associated with TyG were estimated using modified Poisson regression models.

RESULTS

During a median follow-up duration of 6 years, 677 new ischaemic stroke cases were identified. After multivariate adjustment, RR (95% CI) values for ischaemic stroke were 1.33 (1.01-1.75), 1.57 (1.17-2.10) and 1.95 (1.34-2.82) in TyG quartile (Q) 2, 3 and 4 groups, respectively, compared with Q1. A significant interaction between TyG index and age for risk of ischaemic stroke (P_interaction < 0.001) was also observed. However, no significant interaction was found between TyG index and other potential risk factors of risk for ischaemic stroke, although there were significant positive associations with female, non-smoker, non-drinker, low or moderate physical activity, non-obese and non-type 2 diabetes mellitus groups.

CONCLUSION

Elevated TyG index is an independent predictor of ischaemic stroke in the general population, and insulin resistance may be positively associated with future stroke risk.

Triglyceride-glucose index is associated with the risk of myocardial infarction: an 11-year prospective study in the Kailuan cohort

Background

The triglyceride–glucose (TyG) index, which is a simple surrogate marker of insulin resistance, has been suggested as a contributor of cardiovascular disease. However, evidence on the effect of long-term elevation of the TyG index exposure on myocardial infarction (MI) is limited. The current study aimed to evaluate the association of baseline and long-term elevation of the TyG index exposure with the risk of MI.

Methods

A total of 98,849 participants without MI at baseline (2006) were enrolled from the Kailuan study. The baseline TyG index was calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. The long-term TyG index was characterized in two ways as follows. The updated mean TyG index was calculated as the mean of TyG index at all previous visits before MI occurred or the end of follow-up; alternatively, the TyG index was calculated as the number of visits with a high TyG index in 2006, 2008, and 2010, ranging from 0 (no exposure) to 3 (had high TyG index at all three study visits). Hazard ratio (HR) and 95% confidence interval (CI) was estimated using multivariable Cox proportion hazard models.

Results

During a median follow-up of 11.03 years, 1555 incident MI occurred. In the multivariable-adjusted model, the risk of MI increased with quartiles of the baseline and updated mean TyG index, the HR in quartile 4 versus quartile 1 was 2.08 (95% CI,1.77–2.45) and 1.58 (1.18–2.12), respectively. Individuals with a high TyG index at all three visits had a 2.04-fold higher risk (95% CI, 1.63–2.56) of MI compared with no exposure. Subgroup analyses showed that the associations were more pronounced in women than in men (P_interaction = 0.0411).

Conclusions

Elevated levels of the baseline and long-term TyG index are associated with an increased risk of MI. This finding indicates that the TyG index might be useful in identifying people at high risk of developing MI.

Diet pattern may affect fasting insulin in a large sample of black and white adults

OBJECTIVE

Dietary modification of insulin resistance may be a strategy for reducing chronic disease. For this study, we tested the hypothesis that higher fasting insulin, a marker for insulin resistance, would be related to diet patterns with a high proportion of carbohydrates, those with a high glycemic index, and those characterized by added sugar and processed starches.

STUDY DESIGN

Data were analyzed on 13,528 nondiabetic participants of the REasons for Geographic and Ethnic Differences in Stroke (REGARDS), an observational study of adults aged ≥45 years residing in 1855 counties across the continental USA. Information on habitual diet was collected using the Block 98 Food Frequency Questionnaire. Percent energy from carbohydrate, glycemic index, and glycemic load were determined for each participant, as well as adherence to five established diet patterns. Logistic regression was used to examine associations of baseline diet characteristics with odds for high fasting insulin [quartiles 3 and 4 (median = 98.9 pmol/L) vs. quartile 1], after adjusting for covariates.

RESULT

Greater percent carbohydrate, glycemic index, and glycemic load, and adherence to sweets/fat and southern diet patterns, was associated with greater odds for high insulin (P for trend <0.05 to <0.0001), whereas adherence to the plant-based and alcohol/salad patterns was associated with lower odds for high insulin (P for linear trend <0.0001).

CONCLUSION

In conclusion, diet pattern is associated with fasting insulin. Future studies are needed to determine if diet interventions designed to lower insulin, perhaps based on the patterns identified in this study, can improve risk for chronic disease.

Elevated blood pressure, cardiometabolic risk and target organ damage in youth with overweight and obesity

BACKGROUND AND AIM

To compare cardiometabolic risk profile and preclinical signs of target organ damage in youth with normal and elevated blood pressure (BP), according to the American Academy of Pediatrics (AAP) guidelines.

METHODS AND RESULTS

This cross-sectional multicenter study included 2739 youth (5-17 year-old; 170 normal-weight, 610 overweight and 1959 with obesity) defined non hypertensive by the AAP guidelines. Anthropometric, biochemical and liver ultrasound data were available in the whole population; carotid artery ultrasound and echocardiographic assessments were available respectively in 427 and 264 youth. Elevated BP was defined as BP ≥ 90th to <95th percentile for age, gender and height in children or BP ≥ 120/80 to <130/80 in adolescents. The overall prevalence of elevated BP was 18.3%, and significantly increased from normal-weight to obese youth. Young people with elevated BP showed higher levels of body mass index (BMI), insulin resistance and a higher prevalence of liver steatosis (45% vs 36%, p < 0.0001) than normotensive youth, whilst they did not differ for the other cardiometabolic risk factors, neither for carotid intima media thickness or left ventricular mass. Compared with normotensive youth, individuals with elevated BP had an odds ratio (95%Cl) of 3.60 (2.00-6.46) for overweight/obesity, 1.46 (1.19-1.78) for insulin-resistance and 1.45 (1.19-1.77) for liver steatosis, controlling for centers, age and prepubertal stage. The odds for insulin resistance and liver steatosis persisted elevated after correction for BMI-SDS.

CONCLUSION

Compared to normotensive youth, elevated BP is associated with increased BMI, insulin resistance and liver steatosis, without significant target organ damage.

Insulin resistance and breast cancer incidence and mortality in postmenopausal women in the Women's Health Initiative

BACKGROUND

Insulin resistance is associated with higher all-cause and cancer-specific mortality in postmenopausal women. However, to the authors' knowledge, information regarding insulin resistance and breast cancer mortality risk is limited. Therefore, the authors examined associations between insulin resistance and breast cancer incidence and mortality in a subsample of Women's Health Initiative participants.

METHODS

A total of 22,837 postmenopausal women with fasting baseline glucose and insulin levels were followed for incident breast cancer and breast cancer mortality. Breast cancers were verified by medical record review and serial National Death Index linkage-enhanced mortality findings. Insulin resistance was estimated using the homeostatic model assessment of insulin resistance (HOMA-IR). Multivariable Cox proportional hazards models were used to compute hazard ratios (HRs) with 95% confidence intervals (95% CIs) for quartile comparisons. Outcomes included breast cancer incidence, deaths from breast cancer, and deaths after breast cancer (breast cancer followed by death from any cause).

RESULTS

During a median of 19.8 years of follow-up of 1328 breast cancer cases, there were 512 deaths reported, 151 of which were from breast cancer. Breast cancer incidence was higher in women in the highest HOMA-IR quartile (HR, 1.34; 95% CI, 1.12-1.61 [P for trend = .003]). Although HOMA-IR was not found to be associated with risk of death from breast cancer (HR, 1.04; 95% CI, 0.60-1.79), women in the highest versus those in the lowest HOMA-IR quartile were at a higher risk of death after breast cancer (HR, 1.78; 95% CI, 1.32-2.39 [P for trend <.001]).

CONCLUSIONS

Higher levels of insulin resistance in postmenopausal women are associated with higher breast cancer incidence and higher all-cause mortality after breast cancer.

The Comparison of Nutritional Value of Human Milk with Other Mammals' Milk

(1) Background: The variation in the concentration of different components found in milk depends on mammalian species, genetic, physiological, nutritional factors, and environmental conditions. Here, we analyse, for the first time, the content of different components (cholesterol concentration and fatty acids composition as well as the overall fat and mineral content determined using the same analytical methods) in milk of different mammal species. (2) Methods: The samples (n = 52) of human, cow, sheep, goat and mare milk were analyzed in triplicate for: cholesterol concentration, fatty acids profile and fat and mineral content (calcium, magnesium, sodium, potassium, iron, zinc). (3) Results: The highest fat content was reported in sheep milk (7.10 ± 3.21 g/dL). The highest cholesterol concentration was observed in bovine (20.58 ± 4.21 mg/dL) and sheep milk (17.07 ± 1.18 mg/dL). The saturated fatty acids were the lowest in human milk (46.60 ± 7.88% of total fatty acids). Goat milk had the highest zinc (0.69 ± 0.17 mg/dL), magnesium (17.30 ± 2.70 mg/dL) and potassium (183.60 ± 17.20 mg/dL) content. Sheep milk had the highest sodium (52.10 ± 3.20 mg/dL) and calcium (181.70 ± 17.20 mg/dL) concentration values. (4) Conclusions: The differences in nutritional value of milk could be perceived as a milk profile marker, helping to choose the best food for human nutrition.

Associations of exposure to metals with the risk of hypertension among an older population aged 40-75 years in rural southwest China

Metal exposure has recently been related to the risk of hypertension. However, the association remains unclear and relevant epidemiologic studies are limited. The present study aimed to assess the associations between exposure to metals and the odds of hypertension, as well as blood pressure (BP) levels. A total of 816 participants were enrolled in southwestern China. Hypertension was defined as a systolic BP (SBP) of ≥140 mmHg or diastolic BP (DBP) of ≥90 mmHg, a self-reported physician diagnosis, or current use of antihypertensive medication. Blood samples were used to detect the levels of exposure to metals, ie, magnesium (Mg), calcium (Ca), iron (Fe), zinc (Zn), arsenic (As), cadmium (Cd), copper (Cu) and lead (Pb). Logistic and linear regression models were used to assess the potential associations. The results show that positive trends for elevated odds of hypertension with increasing quartiles of Fe in a polluted area; and of Mg, Ca and Cu in an unpolluted area. Compared with those in the lowest quartiles, participants in the highest quartiles of Fe, Mg and Ca had 2.7-, 9.0- and 5.1-fold increased odds of hypertension, respectively. High blood Fe and Pb levels in the Cd-polluted area, and Mg and Fe in the unpolluted area were found to be related to increasing SBP and DBP levels. Our findings suggest that exposure to Fe and/or Pb in the polluted area; and Mg, Ca and Fe in the unpolluted area might increase the risk of hypertension or elevate BP levels.

[Expert Council Resolution. Practical Aspects of the Diagnosis and Correction of Potassium and Magnesium Deficiency States]

The article analyzes properties of potassium and magnesium, which may exert vasodilatory, anti-inflammatory, anti-ischemic, antiaggregant, and antiarrhythmic effects. These are extremely important microelements and potentially beneficial therapeutic agents for treatment of cardiovascular diseases.

Predictors of incident hypertension in healthy non-diabetic postmenopausal women with normal renal function

Introduction: We aimed to investigate the incidence of hypertension and to identify potential risk factors in healthy, non-diabetic recently postmenopausal Greek women with normal renal function.Patients and methods: This retrospective cohort study evaluated 141 recently postmenopausal women at baseline and annually thereafter (follow-up time: 1 to 8 years). Blood samples were obtained, and ultrasound evaluations were performed at baseline. A detailed medical history, anthropometric parameters, blood pressure and cardiovascular risk factors were recorded for every woman at each visit. Incident hypertension was defined as the first occurrence of office systolic or diastolic blood pressure, measured at 2 different visits within 2 months or history of initiation of antihypertensive medication.Results: Incident hypertension was diagnosed in 30 out of 141 women (21.3%). The median time to incident hypertension was 3.5 years. Adiposity, elevated cholesterol and triglyceride levels, insulin resistance and parity were positively associated with incident hypertension. In multivariate analysis, however, obesity and insulin resistance were the only statistically significant variables associated with more than 3-fold and 2-fold respectively increased risk of incident hypertension (HOMA-IR, O.R = 1.988, p-value =.043; obesity, O.R = 3.746, p-value =.019).Conclusion: A significant proportion of women entering the menopause present incident hypertension and this is mostly associated with obesity and insulin resistance.

Impact of 3-year changes in fasting insulin and insulin resistance indices on incident hypertension: Tehran lipid and glucose study

Background

To examine the association between changes in fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and insulin-glucose ratio (IGR) levels, over approximately 3 years with incident hypertension.

Methods

A total of 2814 Iranian participants (1123 men) without hypertension and known diabetes at baseline and the first examination were followed for a median of 6.32 years. The associations between quartiles of changes in fasting insulin and IR indices with incident hypertension were assessed using multivariate Cox proportional hazard regression analyses with first quartile as reference. The models were adjusted for baseline values of insulin or each IR index, and age, sex, smoking, physical activity, educational levels, marital status, history of cardiovascular diseases, baseline levels of systolic and diastolic blood pressures, estimated glomerular filtration rate, triglycerides, total cholesterol, high-density lipoprotein cholesterol, fasting plasma glucose (only for insulin change) and both body mass index (BMI) per se, and its change. Akaike's information criteria (AIC) was applied as indicator for goodness of fit of each predictive model. The discrimination ability of models was calculated using the Harrell's C statistic.

Results

During the study, 594 incident cases of hypertension (253 men) were identified. The 4th quartile of changes in insulin, HOMA-IR, and IGR showed hazard ratios (95% confidence interval) of 1.31 (1.01-1.69), 1.18 (0.92-1.52), and 1.53 (1.18-1.98) for hypertension, respectively, in fully-adjusted models. Changes in fasting insulin levels and IR indices showed significant increasing trends for incident hypertension, moving from 1st to 4th quartiles (all P-values < 0.05). Focusing on model fitness, no superiority was found between changes in fasting insulin, HOMA-IR, and IGR to predict incident hypertension. The discriminatory powers of changes in fasting insulin and IR indices as assessed by C index were similar (i.e. about 80%).

Conclusion

Changes in fasting insulin and IR indices were significantly associated with developing hypertension among normotensive population even after considering BMI changes.

Elevated hypertension risk associated with higher dietary acid load: A systematic review and meta-analysis

BACKGROUND & AIMS

The association between dietary acid load and hypertension risk is inconclusive. We conducted a systematic review and meta-analysis to summarize effect of dietary acid load on blood pressure.

METHODS

A comprehensively search was performed in electronic databases including EMBASE, PubMed, Web of Science and Chinese National Knowledge Infrastructure. Summary ORs and their corresponding 95% CIs were computed assuming a randomized model or fixed model.

RESULTS

Ten publications comprising 4 cohort and 6 cross-sectional studies were eligible for meta-analysis. There were 8 studies about potential renal acid load (PRAL) and 4 about net endogenous acid production (NEAP). Essential hypertension was statistically associated with higher PRAL (OR = 1.14, 95% CI = 1.02-1.17). Our findings also demonstrated a positive impact of higher PRAL on elevating both diastolic pressure (WMD = 0.96, 95% CI = 0.67-1.26) and systolic pressure (WMD = 1.57, 95% CI = 1.12-2.03). A 35% increased risk of hypertension associated with higher NEAP was identified (OR = 1.35, 95% CI = 1.03-1.78).

CONCLUSIONS

The current study suggests that dietary acid load might be potential risk factor of hypertension.

Low-Income Residents' Perceptions of Medication Availability

Access to medications is a critical determinant of health which often mediates the effects of diseases and leads to healthier lifestyles. With limited access to pharmacies, neighborhoods become pharmacy deserts. The purpose of this study was to explore the medication needs and perceptions of low-income community residents. A purposive sample of 40 low-income community residents participated in focus groups. Content analysis revealed four themes: transitioning to the present, stereotyping, feelings of disconnectedness, and ideal pharmacy. These findings reiterate the difficulties of living in pharmacy deserts, and decrease the gaps of limited qualitative research in this area.

Diagnosis of obesity and use of obesity biomarkers in science and clinical medicine

The global epidemic of obesity is a major public health problem today. Obesity increases the risk of many chronic diseases, such as type 2 diabetes, coronary heart disease, and certain types of cancer, and is associated with lower life expectancy. The body mass index (BMI), which is currently used to classify obesity, is only an imperfect measure of abnormal or excessive body fat accumulation. Studies have shown that waist circumference as a measure of fat distribution may improve disease prediction. More elaborate techniques such as magnetic resonance imaging are increasingly available to assess body fat distribution, but these measures are not readily available in routine clinical practice, and health-relevant cut-offs not yet been established. The measurement of biomarkers that reflect the underlying biological mechanisms for the increased disease risk may be an alternative approach to characterize the relevant obesity phenotype. The insulin/insulin-like growth factor (IGF) axis and chronic low-grade inflammation have been identified as major pathways. In addition, specific adipokines such as leptin, adiponectin and resistin have been related to obesity-associated health outcomes. This biomarker research, which is currently further developed with the application of high throughput methods, gives important insights in obesity-related disease etiology and pathophysiological pathways and may be used to better characterize obese persons at high risk of disease development and target disease-causing biomarkers in personalized prevention strategies.

Optimism, pessimism, cynical hostility, and biomarkers of metabolic function in the Women's Health Initiative

BACKGROUND

Psychological attitudes reflecting expectations about the future (optimism, pessimism) and people (cynical hostility) independently predict incident cardiovascular disease and possibly diabetes, but underlying biologic pathways are incompletely understood. Herein we examined the cross-sectional relationship between optimism, pessimism, and cynicism and biomarkers of metabolic function in the Women's Health Initiative.

METHODS

Among 3443 postmenopausal women, biomarkers of metabolic function (fasting insulin [FINS] and glucose) were measured at baseline and used to calculate insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]) and pancreatic β-cell activity (homeostasis model assessment of β-cell function [HOMA-B]). Psychological attitudes were assessed by the Life Orientation Test, Revised (full scale, and optimism and pessimism subscales) and the Cook-Medley cynicism subscale. Multivariable linear regression modeled the association of psychological attitudes with biomarker levels, adjusting for sociodemographics, health conditions, and health behaviors. Because obesity promotes insulin resistance and obese individuals tend to report higher levels of pessimism and cynical hostility, an interaction with body mass index (BMI) was explored.

RESULTS

In fully adjusted models, only pessimism remained independently associated with higher FINS and insulin resistance (HOMA-IR). Scoring 1 point higher on the pessimism subscale was associated with a 1.2% higher FINS, whereas scoring 1 SD higher was associated with a 2.7% higher FINS (P = 0.03); results were similar for HOMA-IR. An interaction term with BMI was not significant.

CONCLUSIONS

In multivariable models, higher dispositional pessimism was associated with worse metabolic function; these findings were not modified by obesity status. Results extend prior work by linking pessimism to an objective biomarker of insulin resistance in elderly women.

The relationship between insulin resistance/β-cell dysfunction and diabetic retinopathy in Chinese patients with type 2 diabetes mellitus: the Desheng Diabetic Eye Study

AIM

To investigate the relationship between insulin resistance (IR)/β-cell dysfunction and diabetic retinopathy (DR) in Chinese patients with type 2 diabetes mellitus (T2DM), and to explore further whether there were differences in the relationship among diabetic patients with higher and lower body mass index (BMI).

METHODS

Cross-sectional study. A total of 1466 subjects with T2DM were recruited in a local Desheng Community of urban Beijing from November 2009 to June 2012 for the cohort of Beijing Desheng Diabetic Eye Study. Standardized evaluation was carried out for each participant, including questionnaire, ocular and anthropometric examinations, and laboratory tests. Seven fields 30° color fundus photographs were used for DR grading according to the Early Treatment Diabetic Retinopathy Study protocols. Homeostatis Model Assessment (HOMA) method was employed for IR and β-cell function assessment.

RESULTS

After excluding those participants who were treated with insulin (n=352) or had missing data of fasting insulin (n=96), and further excluding those with poor quality of retinal photographs (n=10), a total of 1008 subjects were included for the final analysis, 406 (40.3%) were men and 602 (59.7%) were women, age ranging from 34 to 86 (64.87±8.28)y. Any DR (levels 14 and above) was present in 278 (27.6%) subjects. After adjusting for possible covariates, the presence of any DR did not correlate with HOMA IR [odds ratio (OR) 1.51, 95% confidence interval (CI) 0.87-2.61, P=0.14] or HOMA β-cell (OR 0.71, 95%CI 0.40-1.26, P=0.25). After stratification by BMI, the presence of any DR was associated positively with HOMA IR (OR 2.46, 95%CI: 1.18-5.12, P=0.016), and negatively with HOMA β-cell (OR 0.40, 95%CI: 0.19-0.87, P=0.021) in the group of patients with higher BMI (≥25 kg/m²). In the group of patients with lower BMI (<25 kg/m²), the presence of any DR was not associated with HOMA IR (OR 1.00, 95%CI: 0.43-2.33, P=1.00) or HOMA β-cell (OR 1.41, 95%CI: 0.60-3.32, P=0.43).

CONCLUSION

The data suggest that higher IR and lower β-cell function are associated with the presence of DR in the subgroup of diabetic patients with higher BMI. However, this association is not statistically significant in diabetic patients with lower BMI.

Insulin resistance and cardiovascular outcomes in the ORIGIN trial

AIMS

In the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial (Clinicaltrials.gov: NCT000069784), titrated doses of basal insulin glargine targeting fasting normoglycaemia had a neutral effect on cardiovascular outcomes. The dose of insulin required to achieve normoglycaemia provides a unique measurement of each individual's resistance to insulin's action, and was therefore used to examine the link between insulin resistance and cardiovascular outcomes.

MATERIALS AND METHODS

Self-titration of insulin doses targeting a fasting plasma glucose ≤5.3 mmoL/L (95 mg/dL) was promoted at every visit and cardiovascular and other serious health outcomes were ascertained. All analyses were restricted to participants allocated to insulin glargine, who added it to lifestyle or 1 glucose-lowering oral agent at randomization. Normoglycaemia was defined as a fasting plasma glucose <5.6 mmol/L and HbA1c <6% at the 2-year visit. The median of the natural logarithm of insulin doses (expressed per kg of fat-free mass), recorded at every visit from randomization until either the penultimate visit or the first occurrence of a cardiovascular outcome, was analysed.

RESULTS

Higher median insulin doses did not reflect incident cardiovascular events overall or in the subset that achieved normoglycaemia. When the dose taken before a cardiovascular event or the penultimate visit was analysed, the adjusted hazard of the composite of cardiovascular death, myocardial infarction or stroke was 0.94 (95% CI 0.88, 1.00) per unit higher dose overall, and 0.91 (95% CI 0.81, 1.01) in the normoglycaemic subset.

CONCLUSIONS

Insulin resistance may not promote cardiovascular outcomes in individuals with dysglycaemia.

Addressing the Perfect Storm: Biomarkers in Obesity and Pathophysiology of Cardiometabolic Risk

BACKGROUND

The worldwide rise of obesity has provoked intensified research to better understand its pathophysiology as a means for disease prevention. Several biomarkers that may reflect various pathophysiological pathways that link obesity and cardiometabolic diseases have been identified over the past decades.

CONTENT

We summarize research evidence regarding the role of established and novel obesity-related biomarkers, focusing on recent epidemiological evidence for detrimental associations with cardiometabolic diseases including obesity-related cancer. The reviewed biomarkers include biomarkers of glucose–insulin homeostasis (insulin, insulin-like growth factors, and C-peptide), adipose tissue biomarkers (adiponectin, omentin, apelin, leptin, resistin, and fatty-acid-binding protein-4), inflammatory biomarkers (C-reactive protein, interleukin 6, tumor necrosis factor α), and omics-based biomarkers (metabolites and microRNAs).

SUMMARY

Although the evidence for many classical obesity biomarkers, including adiponectin and C-reactive protein (CRP), in disease etiology has been initially promising, the evidence for a causal role in humans remains limited. Further, there has been little demonstrated ability to improve disease prediction beyond classical risk factors. In the era of “precision medicine,” there is an increasing interest in novel biomarkers, and the extended list of potentially promising biomarkers, such as adipokines, cytokines, metabolites, and microRNAs, implicated in obesity may bring new promise for improved, personalized prevention. To further evaluate the role of obesity-related biomarkers as etiological and early-disease-prediction targets, well-designed studies are needed to evaluate temporal associations, replicate findings, and test clinical utility of novel biomarkers. In particular, studies to determine the therapeutic implications of novel biomarkers beyond established metabolic risk factors are highly warranted.

Circulating magnesium levels and incidence of coronary heart diseases, hypertension, and type 2 diabetes mellitus: a meta-analysis of prospective cohort studies

BACKGROUND

Data on the associations between circulating magnesium (Mg) levels and incidence of coronary heart diseases (CHD), hypertension, and type 2 diabetes mellitus (T2DM) are inconsistent and inconclusive. The aim of this study was to examine circulating Mg levels in relation to incidence of CHD, hypertension, and T2DM.

METHODS

Prospective cohort studies published before May 2017 were searched through PubMed, EmBase, SCOPUS, and Google Scholar. A total of 11 studies that reported multivariable-adjusted associations of interest were identified. Information on the characteristics of study and participants, exposure, main outcomes, risk estimates, and cofounders was extracted and analyzed.

RESULTS

Of the 11 included studies, 5 reported results on CHD (38,808 individuals [4437 cases] with an average 10.5-year follow-up), 3 on hypertension (14,876 participants [3149 cases] with a 6.7-year follow-up), and 4 on T2DM (31,284 participants [2680 cases] with an 8.8-year follow-up). Comparing the highest to the lowest category of circulating Mg concentration, the pooled relative risks [RRs] (95% confidence intervals [CIs]) were 0.86 (0.74, 0.996), 0.91 (0.80, 1.02), and 0.64 (0.50, 0.81) for incidence of CHD, hypertension, and T2DM, respectively. Every 0.1 mmol/L increment in circulating Mg levels was associated with 4% (RR, 0.96; 95% CI: 0.94, 0.99) reduction in hypertension incidence. No significant linear association was found between circulating Mg levels and incidence of CHD (RR, 0.89; 95% CI: 0.77, 1.03) and T2DM (RR, 0.90; 95% CI: 0.81, 1.002). The observed associations of interest were sensitive to exclusion of individual studies.

CONCLUSIONS

Findings in this meta-analysis suggest that circulating Mg levels are inversely associated with incidence of CHD, hypertension, and T2DM. Additional studies are needed to provide more solid evidence and identify the optimal range of circulating Mg concentration with respect to primary prevention of CHD, hypertension, and T2DM.

db/db Mice Exhibit Features of Human Type 2 Diabetes That Are Not Present in Weight-Matched C57BL/6J Mice Fed a Western Diet

To understand features of human obesity and type 2 diabetes mellitus (T2D) that can be recapitulated in the mouse, we compared C57BL/6J mice fed a Western-style diet (WD) to weight-matched genetically obese leptin receptor-deficient mice (db/db). All mice were monitored for changes in body composition, glycemia, and total body mass. To objectively compare diet-induced and genetic models of obesity, tissue analyses were conducted using mice with similar body mass. We found that adipose tissue inflammation was present in both models of obesity. In addition, distinct alterations in metabolic flexibility were evident between WD-fed mice and db/db mice. Circulating insulin levels are elevated in each model of obesity, while glucagon was increased only in the db/db mice. Although both WD-fed and db/db mice exhibited adaptive increases in islet size, the db/db mice also displayed augmented islet expression of the dedifferentiation marker Aldh1a3 and reduced nuclear presence of the transcription factor Nkx6.1. Based on the collective results put forth herein, we conclude that db/db mice capture key features of human T2D that do not occur in WD-fed C57BL/6J mice of comparable body mass.

Comprehensive Review of the Impact of Dairy Foods and Dairy Fat on Cardiometabolic Risk

Because regular-fat dairy products are a major source of cholesterol-raising saturated fatty acids (SFAs), current US and Canadian dietary guidelines for cardiovascular health recommend the consumption of low-fat dairy products. Yet, numerous randomized controlled trials (RCTs) have reported rather mixed effects of reduced- and regular-fat dairy consumption on blood lipid concentrations and on many other cardiometabolic disease risk factors, such as blood pressure and inflammation markers. Thus, the focus on low-fat dairy in current dietary guidelines is being challenged, creating confusion within health professional circles and the public. This narrative review provides perspective on the research pertaining to the impact of dairy consumption and dairy fat on traditional and emerging cardiometabolic disease risk factors. This comprehensive assessment of evidence from RCTs suggests that there is no apparent risk of potential harmful effects of dairy consumption, irrespective of the content of dairy fat, on a large array of cardiometabolic variables, including lipid-related risk factors, blood pressure, inflammation, insulin resistance, and vascular function. This suggests that the purported detrimental effects of SFAs on cardiometabolic health may in fact be nullified when they are consumed as part of complex food matrices such as those in cheese and other dairy foods. Thus, the focus on low-fat dairy products in current guidelines apparently is not entirely supported by the existing literature and may need to be revisited on the basis of this evidence. Future studies addressing key research gaps in this area will be extremely informative to better appreciate the impact of dairy food matrices, as well as dairy fat specifically, on cardiometabolic health.

Fasting insulin, insulin resistance and risk of hypertension in the general population: A meta-analysis

BACKGROUND

Studies on the association of fasting insulin concentrations or insulin resistance with subsequent risk of hypertension have yielded conflicting results.

OBJECTIVE

To quantitatively assess the association of fasting insulin concentrations or homeostasis model assessment insulin resistance (HOMA-IR) with incident hypertension in a general population by performing a meta-analysis.

METHODS

We searched the PubMed and Embase databases until August 31, 2016 for prospective observational studies investigating the elevated fasting insulin concentrations or HOMA-IR with subsequent risk of hypertension in the general population. Pooled risk ratio (RR) and 95% confidence interval (CI) of hypertension was calculated for the highest versus the lowest category of fasting insulin or HOMA-IR.

RESULTS

Eleven studies involving 10,230 hypertension cases were identified from 55,059 participants. Meta-analysis showed that the pooled adjusted RR of hypertension was 1.54 (95% CI 1.34-1.76) for fasting insulin concentrations and 1.43 (95% CI 1.27-1.62) for HOMA-IR comparing the highest to the lowest category. Subgroup analysis results showed that the association of fasting insulin concentrations with subsequent risk of hypertension seemed more pronounced in women (RR 2.07; 95% CI 1.19-3.60) than in men (RR 1.48; 95% CI 1.17-1.88).

CONCLUSIONS

This meta-analysis suggests that elevated fasting insulin concentrations or insulin resistance as estimated by homeostasis model assessment is independently associated with an exacerbated risk of hypertension in the general population. Early intervention of hyperinsulinemia or insulin resistance may help clinicians to identify the high risk of hypertensive population.

Gender impacts on the correlations between nonalcoholic fatty liver disease and hypertension in a Chinese population aged 45-60 y

No previous study has reported the association between nonalcoholic fatty liver disease (NAFLD) and the risk of hypertension in the Chinese population. Therefore, the aim of this study was to evaluate the relationship between NAFLD and hypertension in a middle-aged Chinese population. The study subject was (a group of) 1006 Chinese adults aged 45-60 y in Shandong Province who participated in the Weifang Nutrition and Health Survey (2014-2015). Hypertension was defined as systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥ 9 0mmHg. NAFLD was defined as the presence of moderate-severe hepatic steatosis (by B-ultrasonic examination), the absence of excessive alcohol use (>20 g/d in men and 10 g/d in women), no use of steatogenic medications within the past six months, no exposure to hepatotoxins, and no history of bariatric surgery. All anthropometric measurements and biochemical data were collected following standard protocols. Multivariate logistic regression analysis was used to identify the association between NAFLD and hypertension with adjustment of potential confounding variables. Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting glucose, SBP, DBP, triglycerides (TG), serum uric acid (SUA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the prevalence of hypertension and NAFLD were significantly higher in males than in females (p < 0.05). Females had significantly higher levels of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C). After adjusting for potential confounders, NAFLD was associated with an increased risk of hypertension in both male and female, with odds ratios (ORs) (95% CI) of 2.152 (1.324-3.498) and 2.133 (1.409-3.229), respectively.

CONCLUSIONS

Our findings indicated that NAFLD was significantly associated with the risk of hypertension in males than in females. However, our findings also need to be confirmed in future prospective studies.

ABBREVIATIONS

BMI: body mass index; WC: waist circumference; WHR: waist-hip ratio; SBP: systolic blood pressure; DBP: diastolic blood pressure; FG: fasting glucose; TG: triglycerides; TC: total cholesterol; HDL-C: high-density lipoprotein cholesterol; SUA: serum uric acid; NAFLD: nonalcoholic fatty liver disease; LDL-C: low-density lipoprotein cholesterol; OR: odds ratio; CI: confidence interval; ALT: alanine aminotransferase; AST: aspartate aminotransferase.

Different Combinations of Glucose Tolerance and Blood Pressure Status and Incident Diabetes, Hypertension, and Chronic Kidney Disease

Background

The impact of different combinations of glucose tolerance and blood pressure status on the development of type 2 diabetes mellitus (T2DM), hypertension (HTN), and chronic kidney disease (CKD) still needs to be investigated.

Methods and Results

A total of 12 808 Iranian adults aged ≥20 years were included in 3 separate analyses to investigate incidence of T2DM, HTN, and CKD. Multivariate Cox proportional hazard models were used to calculate hazard ratios (95% CI). During a median follow‐up of >10 years, the overall incidence rate for T2DM, HTN, and CKD was 12.2, 29.8, and 24.8 per 1000 person‐years. For incident T2DM, considering normal glucose tolerance/normal blood pressure as reference, prediabetes (PreDM)/HTN had the highest risk (hazard ratio: 7.22 [5.71–9.12]) while PreDM/normal blood pressure also showed a significant risk (5.58 [4.41–7.05]). Furthermore, risk of PreDM/HTN was higher than PreDM/normal blood pressure (P<0.05). For incident HTN, normal glucose tolerance/prehypertension was a strong predictor (3.28 [2.91–3.69]); however, addition of PreDM or T2DM did not increase the risk. For incident CKD, every category that included HTN and/or T2DM showed significant risk; this risk was marginally significant for the PreDM/HTN group (1.19 [0.98–1.43], P=0.06). In addition, PreDM/ normal blood pressure was a marginally significant risk factor for incident HTN while normal glucose tolerance/prehypertension was a significant predictor of T2DM.

Conclusions

Presence of HTN was associated with increased risk of T2DM among the PreDM population; however, dysglycemia did not increase the risk of HTN among individuals with prehypertension. For incident CKD, intensive management of HTN and T2DM, rather than their predisease states, should be considered.

Short Communication: Do Cytomegalovirus Antibody Levels Associate with Age-Related Syndromes in HIV Patients Stable on Antiretroviral Therapy?

HIV(+) persons stable on antiretroviral therapy (ART) face early onset of age-related diseases. This may arise from a high burden of cytomegalovirus (CMV). To address the role of CMV, we investigated univariate and multivariate associations between markers of systemic and endothelial inflammation, vascular damage, insulin resistance (IR), neurocognitive decline, and antibodies reactive with CMV. In this study, HIV(+) participants (n = 91) aged >45 years with <50 copies HIV RNA/ml plasma after >2 years on ART were assessed for cardiovascular risk (the D:A:D algorithm), type II diabetes (the HOMA-IR index), and neurocognitive performance. Blood samples were assayed for lipids, T cells, insulin, glucose, C-reactive protein, CX3CL1, sTNF-R1, total immunoglobulin G (IgG), and antibodies reactive with CMV lysate, glycoprotein B, or immediate-early-1. Levels of antibodies detected with the three antigens were tightly correlated. Levels of CMV lysate antibody were higher in patients than in age-matched healthy controls and reflected their nadir CD4 T-cell count (p = .001), total IgG (p = .02), and age (p = .08). Levels of CMV lysate antibody correlated with D:A:D score (p = .04), neurocognitive performance (p = .045), and fasting insulin (p = .02). In multivariable analyses, some associations reflected the effect of age, but CMV lysate antibody and CD8 T-cell counts were significant predictors of the HOMA-IR index (R(2) = 0.09, p = .01) independent of age. We conclude that associations between levels of CMV antibodies, cardiovascular risk, and neurocognitive health in HIV(+) patients stable on ART are moderated by age-associated increases in response to CMV, while CMV antibodies may be independently linked with IR.

Obesity, albuminuria, and gamma-glutamyl transferase predict incidence of hypertension in indigenous Australians in rural and remote communities in northern Australia

OBJECTIVE

To describe the incidence of hypertension in a cohort of Australian Aboriginal and Torres Strait Islanders.

METHOD

A follow-up study conducted among 1831 indigenous population aged 15 years and over without hypertension at baseline from 19 communities in North Queensland during 1997-2008. Main measurements included baseline and follow-up weight, waist circumference, blood pressure, fasting glucose, lipids (triglycerides and cholesterol), gamma-glutamyl transferase, urinary albumin creatinine ratio, self-reported tobacco smoking, alcohol intake and physical activity.

RESULTS

Hundred cases of hypertension developed over 2633.4 person-years giving a crude incidence of hypertension of 22.6 (16.2-31.4) per 1000 person-years in females and 60.0 (47.1-76.6) per 1000 person-years for males. Age standardized overall incidence was 51.9 per 1000 person-years. Aboriginal participants were twice as likely as Torres Strait Islanders to develop hypertension, which increased with age. Obesity (BMI >30) strongly predicted incident hypertension independently of age or sex (adjusted hazard ratio 2.9, 95% confidence interval 1.9-4.8). Albuminuria and elevated gamma-glutamyl transferase increased the risk of hypertension (adjusted hazard ratio 1.4-1.7) in this population.

CONCLUSION

Incidence of hypertension in indigenous Australian adults is nearly double than that of the general Australian population. High background prevalence of obesity, diabetes and albuminuria contributes to this excess. As well as early detection and management of high blood pressure, albuminuria and diabetes in primary care settings, attention should be equally focused on community-level prevention and management of obesity.

Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward

The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.

Presence of hypertension modifies the impact of insulin resistance on incident cardiovascular disease in a Middle Eastern population: the Tehran Lipid and Glucose Study

AIMS

To examine the independent impacts of the homeostasis model assessment of insulin resistance (HOMA-IR) and the updated model (HOMA2-IR) on incident cardiovascular /coronary heart disease in a Middle Eastern population with a high prevalence of cardiovascular disease risk factors.

METHODS

We examined 3777 Iranian people, aged ≥ 30 years, without history of cardiovascular disease and without use of antidiabetic medication at baseline. Both HOMA-IR and HOMA2-IR were log-transformed and categorized into quartiles. The multivariable Cox proportional hazard regression model, adjusted for traditional cardiovascular disease risk factors, was applied to examine the association between HOMA-IR/HOMA2-IR with incident cardiovascular/coronary heart disease, considering the lowest quartile as reference.

RESULTS

During a median follow-up of > 10 years, 197 cardiovascular disease and 181 coronary heart disease events occurred. Among the covariates, we found a significant interaction between hypertension and HOMA-IR/HOMA2-IR for incident coronary heart/cardiovascular disease (all P ≤ 0.01). Among the population without hypertension, the risk of cardiovascular disease significantly increased in the second [hazard ratio 1.96 (95% CI 1.04-3.68)], third [hazard ratio 1.93 (95% CI 1.00-3.75)] and fourth [hazard ratio 2.34 (95% CI 1.15-4.75)] quartiles of HOMA-IR, and the risk of coronary heart disease increased significantly in the fourth quartile of HOMA-IR [hazard ratio 2.30 (95% CI 1.12-4.73)], but no significant association was detected between HOMA-IR and cardiovascular/coronary heart disease in the population with hypertension. Among the populations both with and without hypertension, no risk was found to be associated with HOMA2-IR quartiles however, a 1-unit increase in HOMA2-IR was associated with a significant risk of cardiovascular disease among the non-hypertensive group [hazard ratio 1.60 (95% CI 1.03-2.48); P = 0.03].

CONCLUSIONS

The presence of hypertension modified the impact of HOMA-IR/HOMA2-IR on incident cardiovascular/coronary heart disease. The presence of insulin resistance highlighted a significant and independent risk for cardiovascular disease/coronary heart disease only in the population without hypertension.

Reduction in peripheral vascular resistance predicts improvement in insulin clearance following weight loss

Background

The hyperinsulinemia of obesity is a function of both increased pancreatic insulin secretion and decreased insulin clearance, and contributes to cardiovascular risk. Whilst weight loss is known to enhance insulin clearance, there is a paucity of data concerning the underlying mechanisms. This study was conducted to examine the inter-relationships between changes in sympathetic nervous system (SNS) activity, vascular function and insulin clearance during a weight loss program.

Methods

Seventeen non-smoking, un-medicated individuals aged 55 ± 1 years (mean ± SEM), body mass index (BMI) 33.9 ± 1.7 kg/m², underwent a 4-month hypocaloric diet (HCD), using a modified Dietary Approaches to Stop Hypertension diet, whilst seventeen age- and BMI-matched subjects acted as controls. Insulin sensitivity and insulin clearance were assessed via euglycemic hyperinsulinemic clamp (exogenous insulin clearance); hepatic insulin extraction was calculated as fasting C-peptide to insulin ratio (endogenous insulin clearance); SNS activity was quantified by microneurographic nerve recordings of muscle sympathetic nerve activity (MSNA) and whole-body norepinephrine kinetics; and vascular function by calf venous occlusion plethysmography and finger arterial tonometry.

Results

Weight loss averaged −8.3 ± 0.6 % of body weight in the HCD group and was accompanied by increased clamp-derived glucose utilization (by 20 ± 9 %, P = 0.04) and exogenous insulin clearance (by 12 ± 5 %, P = 0.02). Hepatic insulin extraction increased from 6.3 ± 0.8 to 7.1 ± 0.9 (P = 0.09). Arterial norepinephrine concentration decreased by −12 ± 5 %, whole-body norepinephrine spillover rate by −14 ± 8 %, and MSNA by −9 ± 5 bursts per 100 heartbeats in the HCD group (P all >0.05 versus control group). Step-wise regression analysis revealed a bidirectional relationship between enhanced exogenous insulin clearance post weight loss and reduction in calf vascular resistance (r = −0.63, P = 0.01) which explained 40 % of the variance. Increase in hepatic insulin extraction was predicted by enhanced finger reactive hyperaemic response (P = 0.006) and improvement in oral glucose tolerance (P = 0.002) which together explained 64 % of the variance.

Conclusions

Insulin clearance is independently and reciprocally associated with changes in vascular function during weight loss intervention.

Trial registration ClinicalTrials.gov: NCT01771042 and NCT00408850

Evidence of insulin resistance in adult uncomplicated malaria: result of a two-year prospective study

The study aimed at investigating the effects of adult uncomplicated malaria on insulin resistance. Fasting levels of blood glucose (FBG), glycosylated hemoglobin (HbA1c), and serum insulin were measured in 100 diabetics and 100 age-matched controls before and during Plasmodium falciparum malaria. Insulin resistance and beta cell function were computed by homeostatic models assessment of insulin resistance (HOMAIR) and beta cell function (HOMAB) formulae, respectively. Body mass index (BMI) was computed. At baseline, diabetics had significantly (P < 0.05) higher levels of BMI, FBG, HbA1c, and HOMAIR but lower level of HOMAB than controls. Baseline insulin levels were comparable (P > 0.05) between the two study groups. During malaria, diabetics maintained significantly (P < 0.05) higher levels of BMI, FBG, and HbA1c but lower levels of insulin and HOMAB than controls. Malaria-induced HOMAIR levels were comparable (P > 0.05) between the two study groups but higher than baseline levels. Apart from BMI and HOMAB, mean levels of all the remaining parameters increased in malaria-infected controls. In malaria-infected diabetics, significant (P < 0.05) increase was only observed for insulin and HOMAIR but not the other measured parameters. Uncomplicated malaria increased insulin resistance in diabetics and controls independent of BMI. This finding may have implications for the evolution of T2DM in malaria-endemic regions.

Rapamycin ameliorates nephropathy despite elevating hyperglycemia in a polygenic mouse model of type 2 diabetes, NONcNZO10/LtJ

While rapamycin treatment has been reported to have a putatively negative effect on glucose homeostasis in mammals, it has not been tested in polygenic models of type 2 diabetes. One such mouse model, NONcNZO10/LtJ, was treated chronically with rapamycin (14 ppm encapsulated in diet) and monitored for the development of diabetes. As expected, rapamycin treatment accelerated the onset and severity of hyperglycemia. However, development of nephropathy was ameliorated, as both glomerulonephritis and IgG deposition in the subendothelial tuft were markedly reduced. Insulin production and secretion appeared to be inhibited, suppressing the developing hyperinsulinemia present in untreated controls. Rapamycin treatment also reduced body weight gain. Thus, rapamycin reduced some of the complications of diabetes despite elevating hyperglycemia. These results suggest that multiple factors must be evaluated when assessing the benefit vs. hazard of rapamycin treatment in patients that have overt, or are at risk for, type 2 diabetes. Testing of rapamycin in combination with insulin sensitizers is warranted, as such compounds may ameliorate the putative negative effects of rapamycin in the type 2 diabetes environment.