Non-linear associations of HOMA2-IR with all-cause mortality in general populations: insights from NHANES 1999-2006

BACKGROUND

The association between homeostatic model assessment (HOMA2-IR) and mortality in obese and non-obese populations has not been clearly explained.

METHODS

A total of 7,085 individuals aged ≥ 20 years from the 1999-2006 National Health and Nutrition Examination Survey were included in the study. Study endpoints were all-cause and cardiovascular mortality. Multivariate Cox proportional hazards regression models with restricted cubic spline analysis were used for analysis.

RESULTS

In the study populations, a total of 1666 all-cause deaths and 555 cardiovascular (CV) deaths were recorded during a mean follow-up of 195.53 months. Notably, a significant difference in obesity was observed in the association between HOMA2-IR and mortality. After adjustment for multiple variables, HOMA2-IR was positively associated with all-cause mortality in all participants, in those with normal BMI, and in those with obesity. Conversely, tertile 2 of HOMA2-IR was associated with a lower risk of all-cause mortality in participants with obesity compared with tertile 1 (adjusted hazard ratio, 0.68; 95% confidence interval, 0.52-0.89; P = 0.005). Results from restricted cubic spline analysis showed a J-shaped association between HOMA2-IR and all-cause and CV mortality. In addition, a nonlinear U-shaped correlation with all-cause (P for nonlinear < 0.001) and CV (P for nonlinear = 0.002) mortality was observed in the population with obesity, with inflection points of HOMA2-IR identified at 1.85 and 1.75. Below the inflection point of 1.85, a negative relationship between HOMA2-IR and all-cause mortality was observed.

CONCLUSIONS

Elevated HOMA2-IR showed a notable correlation with increased risk of all-cause mortality. It was noteworthy that excessively reduced levels of insulin resistance showed a distinct association with increased mortality in individuals with obesity.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effects of intragastric balloon placement in metabolic dysfunction-associated fatty liver disease: A systematic review and meta-analysis

BACKGROUND

Metabolic dysfunction-associated fatty liver disease corresponds to a clinical entity that affects liver function triggered by the accumulation of fat in the liver and is linked with metabolic dysregulation.

AIM

To evaluate the effects of the intragastric balloon (IGB) in patients with metabolic dysfunction-associated fatty liver disease through the assessment of liver enzymes, imaging and several metabolic markers.

METHODS

A comprehensive search was done of multiple electronic databases (MEDLINE, EMBASE, LILACS, Cochrane and Google Scholar) and grey literature from their inception until February 2021. Inclusion criteria involved patients with a body mass index > 25 kg/m² with evidence or previous diagnosis of hepatic steatosis. Outcomes analyzed before and after 6 mo of IGB removal were alanine aminotransferase (IU/L), gamma-glutamyltransferase (IU/L), glycated hemoglobin (%), triglycerides (mg/dL), systolic blood pressure (mmHg), homeostatic model assessment, abdominal circumference (cm), body mass index (kg/m²) and liver volume (cm³).

RESULTS

Ten retrospective cohort studies evaluating a total of 508 patients were included. After 6 mo of IGB placement, this significantly reduced alanine aminotransferase [mean difference (MD): 10.2, 95% confidence interval (CI): 8.12-12.3], gamma-glutamyltransferase (MD: 9.41, 95%CI: 6.94-11.88), glycated hemoglobin (MD: 0.17%, 95%CI: 0.03-0.31), triglycerides (MD: 38.58, 95%CI: 26.65-50.51), systolic pressure (MD: 7.27, 95%CI: 4.79-9.76), homeostatic model assessment (MD: 2.23%, 95%CI: 1.41-3.04), abdominal circumference (MD: 12.12, 95%CI: 9.82-14.41) and body mass index (MD: 5.07, 95%CI: 4.21-5.94).

CONCLUSION

IGB placement showed significant efficacy in improving alanine aminotransferase and gamma-glutamyltransferase levels in patients with metabolic dysfunction-associated fatty liver disease as well as improving metabolic markers related to disease progression.

Relationship between Insulin-Resistance Processing Speed and Specific Executive Function Profiles in Neurologically Intact Older Adults

This study investigated the relationship between insulin-resistance and constituent components of executive function in a sample of neurologically intact older adult subjects using the homeostasis model assessment (HOMA-IR) and latent factors of working memory, cognitive control and processing speed derived from confirmatory factor analysis. Low-density lipoprotein (LDL), mean arterial pressure (MAP), along with body mass index (BMI) and white matter hypointensity (WMH) were used to control for vascular risk factors, adiposity and cerebrovascular injury. The study included 119 elderly subjects recruited from the University of California, San Francisco Memory and Aging Center. Subjects underwent neuropsychological assessment, fasting blood draw and brain magnetic resonance imaging (MRI). Partial correlations and linear regression models were used to examine the HOMA-IR-executive function relationship. Pearson correlation adjusting for age showed a significant relationship between HOMA-IR and working memory (rp = -.18; p = .047), a trend with cognitive control (rp = -.17; p = .068), and no relationship with processing speed (rp = .013; p = .892). Linear regression models adjusting for demographic factors (age, education, and gender), LDL, MAP, BMI, and WMH indicated that HOMA-IR was negatively associated with cognitive control (r = -.256; p = .026) and working memory (r = -.234; p = .054). These results suggest a greater level of peripheral insulin-resistance is associated with decreased cognitive control and working memory. After controlling for demographic factors, vascular risk, adiposity and cerebrovascular injury, HOMA-IR remained significantly associated with cognitive control, with working memory showing a trend. These findings substantiate the insulin-resistance-executive function hypothesis and suggest a complex interaction, demonstrated by the differential impact of insulin-resistance on processing speed and specific aspects of executive function.

Insulin resistance in euglycemic cirrhosis

BACKGROUND

Insulin resistance (IR) is associated with hepatic fibrosis and cirrhosis, regardless of its etiology but the mechanism of hyperinsulinemia in cirrhosis is still unclear. The current study was designed to assess hyperinsulinemia and pancreatic β-cell function in euglycemic cirrhosis of varied etiology.

METHODS

A cross sectional case control study of 100 subjects. IR was assessed by the Homeostasis Model Assessment (HOMA) and quantitative insulin sensitivity check index in euglycemic cirrhosis of varied etiology and in different stages of cirrhosis. HOMA-β was calculated for insulin secretion ability of pancreatic β-cells in different stages of cirrhosis.

RESULTS

Overall IR in euglycemic cirrhosis was seen in 68.5%. IR was seen in the order hepatitis C (100%), non-alcoholic fatty liver disease (100%), autoimmune hepatitis (100%), hepatocellular carcinoma (80%), alcoholic liver disease (72%) and hepatitis B (45%). HOMA-IR value was raised in Child Turcotte Pugh (CTP) score >9 (P value 0.0004) and model of end stage liver disease (MELD) score >15 (P value 0.02). HOMA-β was raised in CTP score >9 (P value 0.02) and MELD score >15 (P value 0.0003). HOMA-β level among diabetic controls was 27.1±7.7 compared to 154.6±80.7 in euglycemic cases (P value <0.0001).

CONCLUSION

IR is common in euglycemic cirrhosis and with advancement of liver disease; there is a compensatory increase in pancreatic β-cell insulin secretion to overcome the IR. However, over a period of time with fall in β-cell function development of hepatogenous diabetes may occur.

The role of resistance and aerobic exercise training on insulin sensitivity measures in STZ-induced Type 1 diabetic rodents

Individuals with Type 1 Diabetes Mellitus (T1DM) can develop insulin resistance. Regular exercise may improve insulin resistance partially through increased expression of skeletal muscle GLUT4 content.

OBJECTIVE

To examine if different exercise training modalities can alter glucose tolerance through changes in skeletal muscle GLUT4 content in T1DM rats.

METHODS

Fifty rats were divided into 5 groups; control, diabetic control, diabetic resistance exercised, and diabetic high and low intensity treadmill exercised. Diabetes was induced using multiple low dose Streptozotocin (20 mg/kg/day) injections and blood glucose concentrations were maintained moderately hyperglycemic through subcutaneous insulin pellets. Resistance trained rats climbed a ladder with incremental loads, while treadmill trained rats ran on a treadmill at 27 or 15 m/min, respectively, all for 6 weeks.

RESULTS

At weeks 3 and 6, area under the curve measurements following an intravenous glucose tolerance test (AUC-IVGTT) in all diabetic groups were higher than control rats (p<0.05). At 6 weeks, all exercise groups had significantly lower AUC-IVGTT values than diabetic control animals (p<0.05). Treadmill trained rats had the lowest insulin dose requirement of the T1DM rats and the greatest reduction in insulin dosage was evident in high intensity treadmill exercise. Concomitant with improvements in glucose handling improvements, tissue-specific elevations in GLUT4 content were demonstrated in both red and white portions of vastus lateralis and gastrocnemius muscles, suggesting that glucose handling capacity was altered in the skeletal muscle of exercised T1DM rats.

CONCLUSIONS

These results suggest that, while all exercise modalities can improve glucose tolerance, each mode leads to differential improvements in insulin requirements and protein content alterations.

Repeat antenatal steroid exposure and later blood pressure, arterial stiffness, and metabolic profile

OBJECTIVE

To determine the relationship between repeat courses of antenatal corticosteroids (ACS) and risk factors for cardiovascular disease in adolescents and young adults.

STUDY DESIGN

We assessed body mass index, blood pressure, arterial stiffness, blood lipids, and insulin resistance (IR) in a Swedish population-based cohort (n = 100) at a median age of 18 (range 14-26) years. Fifty-eight subjects (36 males) had been exposed to 2-9 weekly courses of antenatal betamethasone and 42 (23 males) were unexposed subjects matched for age, sex, and gestational age (GA).

RESULTS

There were no significant differences between the groups regarding body mass index, systolic or diastolic blood pressures, arterial stiffness measured by augmentation index, blood lipids, IR, or morning cortisol levels either in simple regression or in multivariable models. However, more subjects with elevated augmentation index had been exposed to repeat courses of ACS (n = 7) compared with unexposed subjects (n =1, P = .06), and glucose, insulin, and IR correlated inversely to GA at start of ACS (P < .01).

CONCLUSIONS

Repeat courses of ACS did not correlate to adverse cardiovascular risk profile in adolescence and young adulthood, but long-standing effects on the arterial tree and glucose metabolism, the latter dependent on GA at ACS exposure, cannot be excluded. These observations have clinical implications for the ongoing discussion on short-term benefits and long-term safety of repeat ACS treatment.