Elevated 1-h plasma glucose following 75-g oral glucose load is a predictor of arterial stiffness in subjects with normal glucose tolerance

One-Hour Post-Load Plasma Glucose Levels are Associated with Early Arterial Stiffness in Subjects with Different Glucose Tolerance

OBJECTIVE

The purpose of this study was to explore the relationship between one-hour post-load plasma glucose levels and early arterial stiffness in subjects with different glucose tolerance.

METHODS

This case-control study included 57 subjects with normal glucose tolerance, 38 subjects with pre-diabetes, and 30 subjects with type 2 diabetes. All subjects underwent an oral glucose tolerance test (OGTT) with 75 g of oral anhydrous glucose at 8:00 AM. The brachial-ankle pulse wave velocity (baPWV) was used as a surrogate marker of early arterial stiffness.

RESULTS

baPWV was significantly higher in the diabetes group than in the normal glucose tolerance group (diabetes group: 1501.8 ± 270.4 cm/s, pre-diabetes group: 1428.6 ± 173.1 cm/s vs normal glucose tolerance group: 1368.0 ± 242.8 cm/s) (p < 0.05). baPWV was positively correlated with age (r = 0.512, p < 0.001), systolic blood pressure (SBP) (r = 0.526, p < 0.001), diastolic blood pressure (DBP) (r = 0.298, p = 0.001), fasting plasma glucose (FPG) (r = 0.213, p = 0.017), 1-h plasma glucose levels from the OGTT (r = 0.407, p < 0.001) and 2-h plasma glucose levels from the OGTT (r = 0.202, p = 0.024). When baPWV was considered as the dependent variable in a multiple regression analysis, the 1-h plasma glucose level from the OGTT maintained an independent association with baPWV (β = 23.129, 95% CI: 8.142-38.115, p = 0.003, R² = 0.036).

CONCLUSION

The present study demonstrated the presence of early arterial stiffness in diabetes. Elevated 1-hour post-load plasma glucose level is closely related to the change of arterial elasticity in diabetes.

One-hour plasma glucose concentration can identify elderly Chinese male subjects at high risk for future type 2 diabetes mellitus: A 20-year retrospective and prospective study

AIM

There have been few reports regarding the association between 1 h-PG concentration and type 2 diabetes mellitus (T2DM) in the elderly. This study was performed to assess the efficacy of 1 h-PG and 2 h-PG values in predicting future risk of T2DM in elderly.

METHODS

The study population consisted of 928 male volunteers ≥ 55 years old without diabetes who were involved in a retrospective-prospective cohort study over 20 years with a baseline fasting plasma glucose (FPG) and OGTT that included measurement of 1 h-PG and 2 h-PG. The predictive capabilities of FPG and 1 h-PG, 2 h-PG values obtained during OGTT alone and added to a clinical prediction model consisting of traditional diabetes risk factors were assessed.

RESULTS

Overall, 577 of all the 928 study participants (62%) developed T2DM over the 20-year follow-up. 1 h-PG and 2 h-PG values predicted T2DM and remained independent predictors of T2DM after adjusting for various traditional risk factors [HR = 1.269 (95% CI = 1.214-1.327), P < 0.001; HR = 1.269 (95% CI = 1.179-1.366), P < 0.001, respectively]. C-statistics for 1-h PG (C-statistics 0.794 [95% CI 0.765-0.823]) was significantly greater than that for 2-h PG (C-statistic 0.747 [95% CI 0.716-0.779]) in models adjusting for various traditional risk factors. 1 h-PG had the greatest area under the ROC curve (AUC, 0.766), which was greater than that of 2 h-PG (0.719).

CONCLUSIONS

1 h-PG is useful as a predictor of future development of T2DM independently of traditional risk factors in an elderly Chinese male population.

Postloading insulinemia is independently associated with arterial stiffness in young Japanese persons

Associations of arterial stiffness with glucose, insulin, and proinsulin dynamics during the oral glucose tolerance test (OGTT) remain under debate. The aim of this study was to investigate whether plasma glucose (PG), insulin, and proinsulin (Pro) contribute to arterial stiffness, measured by pulse wave velocity (PWV), in young Japanese persons. PG, immunoreactive insulin (IRI), and Pro levels were determined in 1193 young Japanese subjects (<40 years of age) with normal glucose tolerance or nondiabetic hyperglycemia before and at 30, 60, and 120 min during a 75-g OGTT. Participants were divided into two groups according to the median PWV. Background factors, PG, IRI, and Pro levels during the OGTT, and insulin sensitivity (SI) indices in each group were compared. Several multiple regression analysis models were used to evaluate factors contributing to PWV. All IRI and Pro levels before and after glucose loading and the area under the curve (AUC) values for IRI and Pro increased with higher PWV. 1/HOMA-IR and ISI-Matsuda as measures of SI decreased with higher PWV. The IRI AUC and Pro level before glucose loading (Pro0) were independently associated with PWV, in addition to male sex, heart rate, and mean blood pressure. The IRI AUC had a stronger relationship with PWV than Pro0. The IRI AUC had an independent relationship with PWV, whereas both SI indices did not. Postloading insulinemia, but not reduced SI, was independently associated with arterial stiffness in young Japanese persons.

Comparison of serum amylase level between dipeptidyl peptidase-4 inhibitor and GLP-1 analog administration in patients with type 2 diabetes mellitus

We monitored serum amylase level in patients with type 2 diabetes mellitus (T2DM) prescribed either dipeptidyl peptidase-4 inhibitor or GLP-1 analog (GLP-1 group) as monotherapy. Patients were treated for a 36-month period. All subjects were non-smoker and did not take any alcoholic beverages. Forty-nine patients were prescribed DPP4is (DPP4i group), and 9 patients were prescribed GLP-1 analogs (GLP-1 group). The median of serum amylase levels in DPP4is group was 73 U/mL and the median of serum amylase levels in GLP-1 analog group was 76. Thus, there was no statistical significance between the two groups. However, the increased serum amylase levels in the three patients were observed only in the DPP4is group. One strength of the current study is that the serum amylase level was consistently measured in all subjects, and those subjects had been treated with either DPP4is or GLP-1 analogs as monotherapy. The incidence of elevated serum pancreatic amylase levels beyond normal range was calculated as 6.12% in the DPP4is group although the frequency was 0% in the GLP-1 analog group. Measurement of serum amylase consistently might have clinical meaning to catch the onset of pancreatitis and minimize the side effects due to DPP4is and GLP-1 analogs.

Synergistic Effects of 1 h Post-Load Plasma Glucose and Smoking on Arterial Stiffness in Apparently Healthy Men: A Cross-sectional Study

Aim: One-hour post-load plasma glucose (1h-PG) during an oral glucose tolerance test and smoking are associated with arterial stiffness. However, it remains unknown whether there are synergistic effects of these two factors on arterial stiffness. This study aimed to investigate the interaction between 1h-PG and smoking in relation to brachial–ankle pulse wave velocity (baPWV) in young men with normal glucose tolerance (NGT).

Methods: The study included 25-, 30-, 35-, 40-, and 45-year-old non-industrial male workers (n = 2189) who underwent a detailed health check-up. Normotensive participants with NGT and taking no medication were included.

Results: A univariate linear regression analysis showed that 1h-PG correlated with baPWV (r = 0.13, p < 0.001), but the correlation was not significant in the multivariate analysis (β = 0.02, p = 0.24). However, we found a significant interaction between 1h-PG levels and smoking status in relation to baPWV (p = 0.048). Therefore, further analyses were conducted in nonsmokers and smokers. A multivariate linear regression analysis revealed that 1h-PG significantly correlated with baPWV in smokers (β = 0.11, p = 0.02), but not in nonsmokers (β = 0.01, p = 0.79). The correlation remained significant even after adjustment for the number of cigarettes smoked per day (β = 0.096, p = 0.048) or the Brinkman index (β = 0.097, p = 0.043).

Conclusion: A significant interaction between 1h-PG and smoking in relation to baPWV was found in apparently healthy men younger than 50 years old.

Association between 1-h post-load plasma glucose levels and arterial stiffness in normotensive subjects with normal glucose tolerance

OBJECTIVE

To investigate the relationship between 1-h post-load plasma glucose, measured during an oral glucose tolerance test, and arterial stiffness, determined by brachial-ankle pulse-wave velocity, in normotensive subjects with normal glucose tolerance.

METHODS

Study subjects were non-industrial workers aged 25-55 years ( n = 8381) who underwent a regular health check-up every 5 years. We included only normotensive subjects with normal glucose tolerance based on the American Diabetes Association criteria. Subjects taking medication and having an abnormal ankle-brachial index (⩽1.0 or ⩾1.3) were excluded. The final sample comprised 4970 participants (mean age: 38.8 ± 9.4 years; women: n = 2048).

RESULTS

1-h post-load plasma glucose correlated with brachial-ankle pulse-wave velocity in men ( β = 0.04, p = 0.01), but not women ( β = -0.03, p = 0.13) in multivariate linear regression analysis. We found a significant interaction between 1-h post-load plasma glucose and age in men ( p = 0.04); therefore, a subgroup analysis was performed in each 5-year age group. The correlation between 1-h post-load plasma glucose and brachial-ankle pulse-wave velocity was significant in the 55-year-old age group ( β = 0.12, p = 0.01) and neared significant in 45-year-old ( β = 0.08, p = 0.07) and 50-year-old ( β = 0.09, p = 0.07) age groups.

CONCLUSION

Elevated 1-h post-load plasma glucose levels were associated with arterial stiffness in normotensive, middle-aged men with normal glucose tolerance.

Continuous or Transient High Level of Glucose Exposure Differentially Increases Coronary Artery Endothelial Cell Proliferation and Human Colon Cancer Cell Proliferation

We studied effect of high glucose levels on coronary artery endothelial cell proliferation and human colon cancer cell proliferation. To examine the long-term effect of glucose exposure on cell growth, cells were cultured for 14 days in the absence or presence of 183 mg/dL D-glucose addition in the culture medium. Short effect of elevated glucose levels was examined by addition of 183 mg/dL D-glucose addition in the culture medium for just one hour per day followed by changing the culture to standard medium (5.5 mM D-glucose) during the next 23-hours period. Cell proliferation was estimated by 2,3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) assay and phosphor-Erk western blot analysis. We found that coronary artery endothelial cell proliferation was significantly increased in the culture medium with the acute one-hour addition of 183 mg/dL D-glucose compared to the absence or chronic presence of 183 mg/dL D-glucose addition in the culture medium. In contrast, colon cancer cell proliferation was significantly increased in the continuous presence of 183 mg/dL D-glucose addition in the culture medium compared to the acute one-hour addition of glucose. The extent of Erk2 phosphorylation paralleled with the relative changes in cellular proliferation in both cell types. Taken together, these results suggested that continuous or transient high level of glucose exposure differentially effects coronary artery endothelial and human colon cancer cell proliferation.

Subcutaneous abdominal adipose tissue is associated with an index of insulin sensitivity/resistance

To assess whether there is any clinical significance for determining the normal range of subcutaneous abdominal fat area, we compared fat area with insulin sensitivity. Visceral and subcutaneous abdominal fat area the L4-L5 thoracic level was determined by computed tomography (CT). Plasma glucose and insulin levels were determined after an overnight fast and calculated by the homeostatic model assessment of insulin resistance (HOMA-IR). We analyzed 350 (180 male and 170 female) subjects whose BMI was 18.5≤BMI<25. The subcutaneous abdominal fat area of the female subjects was 124.7 ± 46.13 cm² and that of male subjects was 77.53 ± 37.53 cm² (mean ± SD). We compared HOMA-IR between subjects whose visceral abdominal fat area was above 100 cm² and subcutaneous abdominal fat area below the mean + 2SD (15 subjects, 6 male and 9 female) with subjects whose visceral abdominal fat area was also above 100 cm² but whose subcutaneous abdominal fat area was above the mean + 2SD (20 subjects, 7 male and 13 female). The HOMA-IR of the former subjects group was 8.17+/-6.22 and that of the latter subjects group was 3.37+/-2.07 (p = 0.0486). Subjects with increased subcutaneous abdominal fat area displayed lower HOMA-IR values, demonstrating a protective effect of subcutaneous fat for individuals with visceral fat area above 100² cm.

Diabetes Mellitus, Arterial Wall, and Cardiovascular Risk Assessment

Diabetes mellitus is an independent risk factor for atherothrombotic cardiovascular disease. Adults with diabetes are two to four times more likely to develop heart disease or stroke than adults without diabetes. The two major features of diabetes, i.e., hyperglycemia and insulin-resistance, trigger arterial stiffening and increase the susceptibility of the arterial wall to atherosclerosis at any given age. These pathological changes in the arterial wall may provide a functional and structural background for cardiovascular events. The present paper provides a critical overview of the clinical evidence linking diabetes-related metabolic abnormalities to cardiovascular risk, debates the pathophysiologic mechanisms through which insulin resistance and hyperglycemia may affect the arterial wall, and discusses the associations between vascular biomarkers, metabolic abnormalities and cardiovascular events.

β-Cell Function and Insulin Sensitivity in Normal Glucose-Tolerant Subjects Stratified by 1-Hour Plasma Glucose Values

AIM

This study was designed to assess β-cell function and insulin sensitivity indices among normal glucose tolerance (NGT) subjects stratified by 1-h plasma glucose (1hPG) values during an oral glucose tolerance test (OGTT).

MATERIALS AND METHODS

One hundred sixty-six NGT subjects underwent a five-point OGTT, and glucose and insulin levels were estimated. We calculated the following indices: (a) β-cell function (homeostasis assessment model-β-cell function [HOMA-β] and Insulinogenic Index [IGI]) and (b) insulin sensitivity (homeostasis assessment model-insulin resistance [HOMA-IR], Matsuda Index, and Insulin Sensitivity Index [ISI]).

RESULTS

NGT subgroups with elevated 1hPG values (i.e., 1hPG ≥143 to <155 mg/dL and 1hPG ≥155 mg/dL) did not differ from those with 1hPG <143 mg/dL by HOMA-β (P = 0.236) but had significantly lower IGIs (367 ± 239 vs. 257 ± 243 vs. 246 ± 239; P = 0.019). With respect to ISIs, HOMA-IR was not significantly different among the groups (P = 0.103). However, the Matsuda Index (11.2 ± 5.0 vs. 7.4 ± 4.8 vs. 5.5 ± 4.9; P < 0.001) and ISI (0.015 ± 0.010 vs. 0.012 ± 0.006 vs. 0.011 ± 0.011; P = 0.028) were significantly lower in subjects with elevated 1hPG values.

CONCLUSIONS

NGT subjects with elevated 1hPG levels have alterations in β-cell function and insulin sensitivity compared with those with normal 1hPG levels.

Normal Glucose Tolerance with a High 1-Hour Postload Plasma Glucose Level Exhibits Decreased β-Cell Function Similar to Impaired Glucose Tolerance

BACKGROUND

Subjects with normal glucose tolerance (NGT) who have a high 1-hour postload plasma glucose level (≥155 mg/dL; NGT 1 hour-high) have been shown to be at higher risk for type 2 diabetes than subjects with NGT 1 hour-low postload plasma glucose level (<155 mg/dL). We compared β-cell function in subjects with NGT 1 hour-high, NGT 1 hour-low, and impaired glucose tolerance (IGT).

METHODS

We classified subjects into NGT 1 hour-low (n=149), NGT 1 hour-high (n=43), and IGT (n=52). The β-cell function was assessed based on insulinogenic index (IGI), oral disposition index (DI), and insulin secretion-sensitivity index-2 (ISSI-2).

RESULTS

Insulin sensitivity was comparable between the subjects with NGT 1 hour-high and NGT 1 hour-low. The β-cell function with/without adjusting insulin sensitivity was significantly different among the three groups. The IGI (pmol/mmol) was 116.8±107.3 vs. 64.8±47.8 vs. 65.8±80.6 (P=0.141), oral DI was 3.5±4.2 vs. 1.8±1.4 vs. 1.8±3.1 (P<0.001), and ISSI-2 was 301.2±113.7 vs. 213.2±67.3 vs. 172.5±87.5 (P<0.001) in NGT 1 hour-low, NGT 1 hour-high, and IGT, respectively. Post hoc analyses revealed that oral DI and ISSI-2 were significantly different between NGT 1 hour-low and NGT 1 hour-high but comparable between NGT 1 hour-high and IGT.

CONCLUSION

Among Korean subjects with NGT, those who have a higher 1-hour postload glucose level have a compromised insulin-sensitivity adjusted β-cell function to a similar degree as IGT subjects.

Insulin resistance correlates with the arterial stiffness before glucose intolerance

OBJECTIVE

The elevated plasma glucose level and/or insulin resistance in diabetes or impaired glucose tolerance play important roles in the pathogenesis of arterial stiffness. The present study investigated whether insulin resistance correlated with arterial stiffness before the development of glucose intolerance.

METHODS

We conducted a cross-sectional analysis in 872 young to middle-age individuals with normal glucose tolerance (aged 36.2±8.5 years, BMI 24.6±3.1 kg/m2 [mean±SD]). The homeostasis model assessment (HOMA) index was used as a quantitative assessment of the fasting insulin resistance (FIR), and the plasma insulin level after glucose loading was adopted as an index of the post-challenge insulin resistance (PIR). The Matsuda index [ISI (composite)] was used as a measurement of the insulin sensitivity. The arterial stiffness assessed by the brachial-ankle pulse wave velocity (baPWV) was adopted to quantify its independent associations with insulin resistance.

RESULTS

The univariate linear regression analysis indicated that the fasting plasma glucose level (FPG, β = 68.2; 95% CI 40.9, 95.6; p<0.001), post-challenge plasma glucose level (PPG, β = 25.3; 95% CI 15.6, 35.0; p<0.001), FIR (β = 24.5; 95% CI 14.1, 35.0; p<0.001), PIR (β=1.30; 95% CI 0.87, 1.73; p<0.001) and ISI (composite) (β = -3.55; 95% CI -5.02, -2.07; p<0.001) were all significantly correlated with the baPWV. After adjustment for sex, age, BMI, heart rate, smoking, systolic blood pressure, total cholesterol, LDL-cholesterol and family history of diabetes, the multivariate linear regression analysis demonstrated that the PIR (model 1, β = 0.39, p=0.038; model 2, β = 0.39, p=0.035; model 3, β = 0.39, p=0.035) was an independent contributor to the baPWV, while the FIR, FPG, PPG and ISI (composite) failed to show any significant contribution.

CONCLUSION

The insulin resistance correlated with the arterial stiffness before glucose intolerance.