Insulin resistance: from bit player to centre stage

Relationship Between the Lipid Accumulation Product Index and Arterial Stiffness in the Chinese Population With Hypertension: A Report From the China H-Type Hypertension Registry Study

Background

Lipid accumulation product (LAP) index, as a new index to predict cardiovascular disease (CVD), has attracted the attention of many researchers. The relation of the LAP index with brachial-ankle pulse wave velocity (baPWV) has been evaluated in several previous studies and yielded inconsistent results. This study aimed to investigate the association between the LAP index and arterial stiffness in the Chinese population with hypertension.

Methods

We conducted a cross-sectional analysis in 4,926 Chinese population with hypertension (aged 64.42 ± 9.44 years). The LAP index was developed from population-based frequency plots of adult waist circumferences and circulating triglyceride concentrations according to men and women. Arterial stiffness was determined by measuring baPWV.

Results

The multivariate linear regression analyses showed that the LAP index was independently and positively associated with baPWV [beta coefficients (β), 24.10 cm/s; 95% CI: 5.72, 42.49 cm/s]. Consistently, the multivariate logistic regression analyses showed a positive association between the LAP index risk of elevated baPWV (>75th percentile) [odds ratio (OR), 1.19; 95% CI 1.01, 1.41]. A restricted cubic spline showed that a significant linear association existed between the LAP index and baPWV. In different subgroups of diastolic blood pressure (DBP), there is interaction between the LAP index and baPWV (DBP <90, 90–99, ≥100 mm Hg; p-interaction = 0.006).

Conclusion

LAP is significantly positively associated with baPWV and elevated baPWV in Chinese hypertensive adults and especially among participants with DBP ≤ 99 mm Hg.

Maternal obesity and metabolic disorders associate with congenital heart defects in the offspring: A systematic review

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformations. The aetiology of CHDs is complex. Large cohort studies and systematic reviews and meta-analyses based on these have reported an association between higher risk of CHDs in the offspring and individual maternal metabolic disorders such as obesity, diabetes, hypertension, and preeclampsia, all conditions that can be related to insulin resistance or hyperglycaemia. However, the clinical reality is that these conditions often occur simultaneously. The aim of this review is, in consequence, both to evaluate the existing evidence on the association between maternal metabolic disorders, defined as obesity, diabetes, hypertension, preeclampsia, dyslipidaemia and CHDs in the offspring, as well as the significance of combinations, such as metabolic syndrome, as risk factors.

METHODS

A systematic literature search of papers published between January 1, 1990 and January 14, 2021 was conducted using PubMed and Embase. Studies were eligible if they were published in English and were case-control or cohort studies. The exposures of interest were maternal overweight or obesity, hypertension, preeclampsia, diabetes, dyslipidaemia, and/or metabolic syndrome, and the outcome of interest was CHDs in the offspring. Furthermore, the studies were included according to a quality assessment score.

RESULTS

Of the 2,250 identified studies, 32 qualified for inclusion. All but one study investigated only the individual metabolic disorders. Some disorders (obesity, gestational diabetes, and hypertension) increased risk of CHDs marginally whereas pre-gestational diabetes and early-onset preeclampsia were strongly associated with CHDs, without consistent differences between CHD subtypes. A single study suggested a possible additive effect of maternal obesity and gestational diabetes.

CONCLUSIONS

Future studies of the role of aberrations of the glucose-insulin homeostasis in the common aetiology and mechanisms of metabolic disorders, present during pregnancy, and their association, both as single conditions and-particularly-in combination, with CHDs are needed.

Maternal Obesity and Diabetes Mellitus as Risk Factors for Congenital Heart Disease in the Offspring

Congenital heart disease (CHD) is the most common anatomical malformation occurring live‐born infants and an increasing cause of morbidity and mortality across the lifespan and throughout the world. Population‐based observations have long described associations between maternal cardiometabolic disorders and the risk of CHD in the offspring. Here we review the epidemiological evidence and clinical observations relating maternal obesity and diabetes mellitus to the risk of CHD offspring with particular attention to mechanistic models of maternal‐fetal risk transmission and first trimester disturbances of fetal cardiac development. A deeper understanding of maternal risk factors holds the potential to improve both prenatal detection of CHD by identifying at‐risk pregnancies, along with primary prevention of disease by improving preconception and prenatal treatment of at‐risk mothers.

Adiposity Criteria in Assessing Increased Cardiometabolic Risk in Prepubertal Children

Objective: Adiposity induces the clustering of cardiometabolic risk factors, and pediatric adiposity is a better indicator for adulthood cardiometabolic diseases than pediatric metabolic syndrome. However, the observed prevalence of pediatric adiposity depends on the methods and cut-points used. Therefore, we aimed to define diagnostic criteria for adiposity which enable more valid identification of prepubertal children at increased cardiometabolic risk. Methods: The participants were 470 prepubertal children (249 boys) aged 6-8 years. The measures of adiposity included body mass index-standard deviation score (BMI-SDS), waist-to-height ratio (WHtR) and body fat percentage (BF%) assessed by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). Criteria for adiposity were determined by increased cardiometabolic risk. Cardiometabolic risk factors which correlated with BF% assessed by DXA in the upper but not lower half of BF% (serum insulin and plasma high-density lipoprotein cholesterol, triglycerides, gamma-glutamyl transferase, high-sensitivity C-reactive protein and uric acid) were included in the cardiometabolic risk score (CMS). We computed receiver operating characteristics curves for the measures of adiposity using the ≥90th percentile of CMS as a measure of increased cardiometabolic risk, and local regression curves were graphed to demonstrate the associations of the measures of adiposity with CMS. Results: In girls, WHtR of 0.445 (area under curve 0.778, its 95% confidence interval 0.65-0.91, sensitivity and specificity 0.73) and BF% of 19.5% assessed by BIA (0.801, 0.70-0.90, 0.73) were the best overall criteria for increased cardiometabolic risk. In boys, BMI-SDS of 0.48 (0.833, 0.75-0.92, 0.76) was the best overall criterion for increased cardiometabolic risk. While local regression curves in girls showed that WHtR of 0.445 corresponds well to a point where CMS began to increase, in boys local regression curves suggest that CMS began to increase even at a lower level of BMI-SDS than 0.48. Moreover, the diagnostic ability of the measures of adiposity to exclude increased cardiometabolic risk was poorer than the ability to detect it. Conclusions: In general, the measures of adiposity have sufficient diagnostic accuracy to be utilized as the screening tool for increased cardiometabolic risk. The observed cut-points for adiposity were lower than the traditional cut-points for adiposity.

Insulin Therapy Increases Cardiovascular Risk in Type 2 Diabetes

Insulin therapy increased cardiovascular (CV) risk and mortality among type 2 diabetes (T2D) patients in several recently reported clinical outcomes trials. To assess whether this association is causative or coincidental, PubMed searches were used to query the effects of insulin therapy for T2D on CV health and longevity from large-scale outcomes trials, meta-analyses, and patient registry studies, as well as basic research on insulin's direct and pleiotropic actions. Although several old studies provided conflicting results, the majority of large observational studies show strong dose-dependent associations for injected insulin with increased CV risk and worsened mortality. Insulin clearly causes weight gain, recurrent hypoglycemia, and, other potential adverse effects, including iatrogenic hyperinsulinemia. This over-insulinization with use of injected insulin predisposes to inflammation, atherosclerosis, hypertension, dyslipidemia, heart failure (HF), and arrhythmias. These associations support the findings of large-scale evaluations that strongly suggest that insulin therapy has a poorer short- and long-term safety profile than that found to many other anti-T2D therapies. The potential adverse effects of insulin therapy should be weighed against proven CV benefits noted for select other therapies for T2D as reported in recent large randomized controlled trials.

Effects of febuxostat on insulin resistance and expression of high-sensitivity C-reactive protein in patients with primary gout

We aimed to investigate the effects of febuxostat on IR and the expression of high-sensitivity C-reactive protein (hs-CRP) in patients with primary gout. Forty-two cases of primary gout patients without uric acid-lowering therapy were included in this study. After a physical examination, 20 age- and sex-matched patients were included as normal controls. The levels of fasting insulin (INS), fasting blood glucose (FBG), and hs-CRP were determined. IR was assessed using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). Gout patients had higher levels of UA, INS, HOMA-IR, and hs-CRP than normal controls (P < 0.05). After 4-, 12-, and 24-week febuxostat treatments, UA and hs-CRP concentrations were significantly lower than baseline (P < 0.05). INS and HOM-IR decreased slightly after a 4-week treatment with febuxostat but declined significantly after 12 and 24 weeks of treatment. Importantly, hs-CRP values positively correlated with those of HOMA-IR (r = 0.353, P = 0.018) and INS (r = 0.426, P = 0.034). Our findings confirm that IR exists in gout patients and implicate that febuxostat can effectively control the level of serum UA and increase insulin sensitivity in primary gout patients.

Relation of insulin resistance with social-demographics, adiposity and behavioral factors in non-diabetic adult Canadians

BACKGROUND

Insulin resistance is a pathogenic factor for type II diabetes and has been associated with metabolic abnormalities and adverse clinical outcomes. The purpose of this study was to examine the relationship between insulin resistance and socio-demographics, adiposity and behavioral factors in the general, non-diabetic adult Canadian population.

METHODS

Data for 3515 non-diabetic adults aged 18 to 79 years from the Canadian Health Measures Survey (cycles 1 and 2, 2007-2011) were analyzed. Insulin resistance index was measured by the homeostasis model assessment of insulin resistance (HOMA-IR), and insulin resistance (IR) was defined as individuals in the highest quartile of the HOMA-IR index. Logistic regression models were used to examine the effect of demographics, lifestyle factors and adiposity measurements on HOMA-IR.

RESULTS

The risk of IR increased with age, particularly in men. Individuals had adjusted odds ratio (OR) (with corresponding 95 % confidence interval) of 5.97 (2.90-8.52) and 25.12 (15.20-41.51) associated with a body-mass-index (BMI) between 25.0 and < 30.0, or ≥30.0, of 9.23 (6.52-13.07) with abdominal obesity (waist circumstance ≥102 cm for men and ≥ 88 cm for women), of 8.72 (6.13-12.39) with a high waist-to-height ratio (>0.57), and of 6.30 (4.33-9.16) with a high waist-to-hip ratio (>0.90 for men and >0.85 for women). Physically inactive people and non-alcohol consumer also had a significantly higher odd of IR.

CONCLUSIONS

This study found that men and older, obese and physically inactive people were at increased risk for IR. Adiposity indices including BMI, waist circumstance, waist-to-height ratio and waist-to-hip ratio were highly associated with IR with similar magnitude of association.

In quest for method of insulin resistance assessment in everyday clinical practice-Insulin resistance indices

Insulin resistance (IR) a state of decreased sensitivity of target tissues to insulin is suspected usually in obese so can be overlooked in normal weight subjects thus it is important to find optimal method of IR assessment in clinical practice.

METHODS

HOMA, HOMA2, QUICKI, Matsuda index were calculated using data obtained from medical history of 130 female subjects - patients of the Department of Endocrinology and Metabolic Diseases, in whom oral glucose tolerance test (OGTT) with parallel insulin concentrations assessment was performed.

RESULTS

IR correlated positively with body mass index (BMI) in the entire study group, regardless which of four analyzed IR indices was used. Insulin resistance occurred in the obese as well as in normal weight and underweight subjects. The incidences of IR in the study group varied, depending upon chosen method and adopted cut-off values.

CONCLUSIONS

The need for quantitative assessment of IR in clinical practice is apparent. Proper selection of the best method of IR assessment remains a problem. HOMA appears the method of first choice for clinical use. There is an urgent need to establish universal or, at least, national standard cut-off values for IR, to introduce IR assessment in clinical practice.

Mortality risk with sulphonylureas compared to metformin

Current clinical guidelines in the USA and the UK recommend first-line glucose-lowering treatment with metformin monotherapy for glucose control in type 2 diabetes, where not contraindicated. Consequently, the proportion of people treated with sulphonylureas is decreasing. The purpose of this commentary is to discuss the risks and benefits associated with sulphonylurea monotherapy versus metformin monotherapy and the evidence that, in comparison with metformin, sulphonylureas cause increased harm to people with type 2 diabetes.

Comparing effects of carbohydrate (CHO) blockers and trivalent chromium on CHO-induced insulin resistance and elevated blood pressure in rats

OBJECTIVE

In Sprague-Dawley rats (SD), we compared two categories of natural dietary supplements that influence carbohydrate (CHO) metabolism via different basic mechanisms to ameliorate insulin resistance (IR) and elevated blood pressure (BP) associated with heavy sugar/starch consumption. Two dietary supplements (bean extract and l-arabinose) are often referred to as carb blockers (CBs), because they slow the gastrointestinal absorption of CHO. Trivalent chromium (CR) falls into a group of so-called insulin sensitizers, because its major effect is to enhance peripheral insulin sensitivity.

METHOD

We divided 48 mature male SD into 4 groups of 12. The first group received powdered baseline diet alone (Con). The remaining 3 SD groups (groups 2-4) ingested regular rat chow containing 20% w/w sucrose and 20% w/w rice starch. The second group received only this CHO-enriched chow. To the high-CHO diets of the remaining two groups, either CB to slow CHO absorption (CHO + CB) (group 3) or an insulin sensitizer, trivalent CR (CHO + CR; group 4), was added.

RESULTS

Compared to Con group 1, adding high CHO content to the diet of group 2 significantly increased circulating glucose levels and systolic BP (SBP). Addition of CB or CR to the feed of groups 3 and 4 overcame the perturbations that occurred with high CHO challenge in group 2; that is, they lowered circulating glucose concentrations to Con levels, enhanced response to exogenous insulin, and overcame the gradual elevation of SBP. Compared to group 2, the two treatment groups (3 and 4) also showed decreased renin-angiotensin system activity, decreased serum angiotensin-converting enzyme activity, and enhanced nitric oxide activity.

CONCLUSIONS

Our data indicate that high doses of CB and CR, despite their different mechanisms of action, can completely overcome CHO-induced IR and BP elevations. The data further suggest that CB and CR affect only the changes brought on by heavy CHO ingestion, because IR and SBP in groups 3 and 4 mirrored Con values (group 1), never producing values lower than baseline. Earlier use of CB and CR in the life cycle appears more effective in overcoming CHO-induced perturbations than later use.

Comparison of the abilities of the plasma triglyceride/high-density lipoprotein cholesterol ratio and the metabolic syndrome to identify insulin resistance

This study compares the ability of an elevated triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio, using sex-specific cut-points, to identify insulin-resistant individuals within a population without known cardiac disease or diabetes with that obtained using the diagnostic criteria of the metabolic syndrome (MetS). Measurements were made of waist circumference (WC), systolic and diastolic blood pressure, fasting plasma glucose, fasting plasma insulin (FPI), plasma TG and plasma HDL-C concentrations in 1102 women and 464 men. These data were used to classify subjects as being insulin resistant (FPI concentration in the upper quartile) and having the MetS or an elevated TG/HDL-C ratio (>2.5 and >3.5 for women and men, respectively). The sensitivity and specificity with which the two indices identified insulin-resistant subjects were similar (43% and 81% for TG/HDL-C ratio and 45% and 82% for MetS), as the number of individuals was found with either an elevated TG/HDL-C ratio (n = 386) or the MetS (n = 384). Eighty-one per cent of the individuals were identified concordantly. Cardio-metabolic risk profiles in 'low-risk' individuals identified by a low TG/HDL-C ratio were comparable to those who did not have the MetS, and this was also the case when comparing 'high-risk' groups identified by having the MetS or an elevated TG/HDL-C ratio. These findings suggest that TG/HDL-C concentration ratio is as adequate as MetS diagnosis to identify insulin-resistant subjects.

The safety profile of exogenous insulin in people with type 2 diabetes: justification for concern

There is no doubt about the value of exogenous insulin for people with type 1 diabetes. The purpose of this commentary is to discuss emerging evidence that this may not be the case for the majority of people with type 2 diabetes.