The short insulin tolerance test is safe and reproducible

ApoB/ApoA-I ratio is independently associated with carotid atherosclerosis in type 2 diabetes mellitus with well-controlled LDL cholesterol levels

BACKGROUND/AIMS

This study aimed to investigate whether the apolipoprotein (Apo) B/ApoA-I ratio is associated with carotid intima-media thickness (CIMT) in type 2 diabetes mellitus (T2DM) subjects with low density lipoprotein cholesterol (LDL-C) levels less than 100 mg/dL.

METHODS

This cross-sectional study included 845 subjects aged with T2DM 40 to 75 years who had visited Huh's Diabetes Center in Seoul, Republic of Korea for CIMT measurement. Traditional fasting lipid profiles, ApoB and ApoA-I levels were examined. CIMT was measured at three points on the far wall of 1 cm long section of the common carotid artery in the proximity of the carotid bulb. The mean value of six measurements from right and left carotid arteries were used as the mean CIMT. In this study, carotid atherosclerosis was defined as having a focal plaque or diffuse thickening of the carotid wall (mean CIMT ≥ 1.0 mm).

RESULTS

The prevalence of carotid atherosclerosis increased with ApoB/ApoA-I ratio. The ApoB/ApoA-I ratio, expressed as both quartiles (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.21 to 3.79; p for trend = 0.014) and continuous values (OR, 10.05; 95% CI, 3.26 to 30.97; p < 0.001), was significantly associated with a higher risk for carotid atherosclerosis, regardless of conventional cardiovascular disease risk factors. The optimal ApoB/ApoA-I ratio cutoff value for detecting carotid atherosclerosis was 0.57, based on receiver operating characteristic curve analysis with a sensitivity of 58.0% and a specificity of 55.1%.

CONCLUSIONS

A high ApoB/ApoA-I ratio was significantly associated with carotid atherosclerosis in T2DM patients with LDL-C levels less than 100 mg/dL.

Optimal Waist Circumference Cutoff Value Based on Insulin Resistance and Visceral Obesity in Koreans with Type 2 Diabetes

BACKGROUND

Visceral obesity is the most powerful contributor to the development of metabolic syndrome (MetS) and cardiovascular diseases. In light of visceral obesity, however, there is a paucity of data on the appropriate cutoff point of waist circumference (WC) in subjects with type 2 diabetes. The aim of this study was to investigate the optimal cutoff value for WC that signals insulin resistance (IR) and visceral obesity in Koreans with type 2 diabetes.

METHODS

We evaluated 4,252 patients with type 2 diabetes (male 2,220, female 2,032, mean age 57.24 years) who visited our clinic between January 2003 and June 2009. WC was measured at the midpoint between the lower rib and the iliac crest, and insulin sensitivity was assessed by the rate constant of plasma glucose disappearance (Kitt %/min) using an insulin tolerance test. Visceral fat thickness was measured using ultrasonography. Statistical analysis was performed using receiver operating characteristic curve.

RESULTS

The optimal cutoff points for WC for identifying the presence of IR and visceral obesity, as well as two or more metabolic components, were 87 cm for men and 81 cm for women. Moreover, these cutoff points had the highest predictive powers for the presence of visceral obesity. The MetS defined by new criteria correlated with the increased carotid intima-media thickness in female subjects.

CONCLUSION

Our results suggest that the optimal cutoff values for WC in Koreans with type 2 diabetes should be reestablished based on IR and visceral obesity.

The association of insulin resistance and carotid atherosclerosis with thigh and calf circumference in patients with type 2 diabetes

Background

The relationship between body composition parameters such as thigh and calf circumference and insulin resistance or atherosclerosis in type 2 diabetes is poorly understood. The aim of this study was to investigate the relationship between insulin resistance, atherosclerosis, and thigh and calf circumference in patients with type 2 diabetes.

Methods

A total of 4,427 subjects with type 2 diabetes were enrolled in this study. Insulin sensitivity was assessed according the rate constant for plasma glucose disappearance (Kitt) determined via the short insulin tolerance test. Biochemical and anthropometric profiles were measured according to a standardized protocol. Visceral fat thickness and carotid intima media thickness (IMT) were measured by ultrasonography.

Results

Insulin sensitivity index (Kitt) was significantly correlated with weight adjusted thigh and calf circumference. Thigh circumference was inversely associated with IMT in men and women and calf circumference was negatively correlated with IMT in women. Multiple stepwise regression analysis revealed that thigh circumference was independently correlated with insulin sensitivity index (Kitt) and IMT. Furthermore, in multivariate logistic regression analysis, thigh circumference was an independent determinant factor for carotid atherosclerosis in patients with type 2 diabetes even after adjusting for other cardiovascular risk factors.

Conclusions

Thigh and calf circumference were correlated with insulin resistance and carotid atherosclerosis, and thigh circumference was independently associated with insulin resistance and carotid atherosclerosis in patients with type 2 diabetes.

The thermic response to food is related to sensitivity to adrenaline in a group at risk for the development of type II diabetes

OBJECTIVES

To analyze whether a decreased sensitivity to adrenaline in women with earlier gestational diabetes (GDM) explains the impairment in the thermogenic response to food (=post-prandial thermogenesis (PPT)) that is observed in these women at future risk of obesity and type II diabetes.

SUBJECTS/METHODS

Ten normal-weight women with previous GDM and 10 controls matched for body weight, all with normal glucose tolerance, had insulin sensitivity, PPT and the thermogenic response to an adrenaline infusion measured.

RESULTS

Insulin sensitivity was similar in the previous GDM compared with control groups: (mean+/-s.e.m.) 29.1+/-3.2 vs 30.9+/-1.6 mg/l/min. The early (0-30 min) PPT response was diminished and delayed in women with previous GDM compared with controls: (10+/-2 vs 15+/-1 kJ, P=0.04); time constant for PPT (median (interquartile range)) (57 (47-79) vs 29 (25-49) min, P=0.01). The overall PPT response and the thermogenic response to adrenaline were not significantly different between the groups. The 30 min and 2 h PPT response correlated positively and significantly with the increment in energy expenditure as a result of the adrenaline infusion (rho=+0.65; P=0.04 and rho=+0.71; P=0.02, respectively) in women with previous GDM only. There was no correlation between adrenaline and insulin sensitivity.

CONCLUSIONS

There is no evidence of diminished adrenaline sensitivity but a positive relationship exists between PPT and sensitivity to adrenaline in women with previous GDM. The mechanism is not mediated through insulin resistance. This relationship may predispose these normal-weight at-risk women to future weight gain.