The role of the body mass index and triglyceride levels in identifying insulin-sensitive and insulin-resistant variants in Japanese non-insulin-dependent diabetic patients

Body Roundness Index Is Better Correlated with Insulin Sensitivity than Body Shape Index in Young and Middle-Aged Japanese Persons

Aims: The present study aimed to clarify the relationships between novel and traditional anthropometric indices and insulin sensitivity (SI) in young and middle-aged Japanese persons with normal glucose tolerance (NGT), and middle-aged Japanese persons with NGT and glucose intolerance. Methods: Plasma glucose and insulin levels were measured in 1270 young (age <40 years) and 2153 middle-aged persons with NGT (n = 1531) and glucose intolerance (n = 622) during a 75-g oral glucose tolerance test. Height (Ht), weight, and waist circumference (WC) were measured. The body mass index (BMI), WC, and the WC/Ht ratio were used as traditional anthropometric indices. A body shape index (ABSI) and the body roundness index (BRI) were calculated as novel indices. Indices of SI (Matsuda index and 1/homeostasis model assessment of insulin resistance) were calculated and compared with anthropometric indices. Results: The ABSI showed a weak correlation with SI indices in all groups. The BRI showed almost the same correlation with SI indices as the BMI, WC, and WC/Ht in all groups. The inverse correlation between each of the anthropometric indices other than ABSI and SI indices was weak in young persons, at 0.16-0.27 (Spearman's ρ values), but strong in middle-aged persons, at 0.38-1.00. On receiver-operating characteristic (ROC) curve analysis for detection of insulin resistance, the ABSI had a lower area under the ROC curve (AUC) than the other anthropometric indices, and the BRI and the WC/Ht ratio showed similar AUCs. The AUCs for the BRI and WC/Ht ratio were the highest in middle-aged men with NGT and glucose intolerance. Conclusions: The BRI, not the ABSI, was better correlated with SI in young and middle-aged Japanese persons. The BRI and WC/Ht ratio were comparable in their correlations with SI and the detection of insulin resistance in the participants of the present study.

Factors that determine glucose variability, defined by the coefficient of variation in continuous glucose monitoring values, in a Chinese population with type 2 diabetes

AIMS

To elucidate the clinical determinants of the coefficient of variation (CV) of glucose by analysing the pancreatic β-cell function of subjects with type 2 diabetes mellitus (T2DM).

METHODS

A total of 716 Chinese subjects with T2DM were included. Continuous glucose monitoring (CGM) was used to assess blood glucose, and the CV was calculated. C-peptide concentration at 0, 0.5, 1, 2 and 3 hours (Cp0h, Cp0.5h, Cp1h, Cp2h and Cp3h, respectively) was measured after a standard 100-g steamed bun meal test to assess pancreatic β-cell function. The determinants of glucose variability defined by the CV of CGM values were explored from two perspectives: the CV of qualitative variables and the CV of quantitative variables.

RESULTS

Our data revealed that C-peptide concentration (Cp0h, Cp0.5h, Cp1h, Cp2h, Cp3h), area under the curve for C-peptide concentration at 0.5 and 3 hours (AUC-Cp0.5h and AUC-Cp3h) decreased with increasing CV quartile (P < 0.05). The CV was negatively correlated with homeostatic model assessment of β-cell function index, C-peptide concentration at all timepoints, and AUC-Cp0.5h and AUC-Cp3h (P < 0.001). Quantile regression analysis showed that AUC-Cp0.5h had an overall negative effect on the CV in the 0.05 to 0.95 quartiles, and AUC-Cp3h tended to have a negative effect on the CV in the 0.2 to 0.65 quartiles. After adjusting for confounders, multinomial logistic regression showed that each 1-unit increase in AUC-Cp0.5h was associated with a 31.7% reduction in the risk of unstable glucose homeostasis (CV > 36%; P = 0.036; odds ratio 0.683; 95% confidence interval 0.478-0.976). We also identified the AUC-Cp0.5h (0.735 ng/mL) and AUC-Cp3h (13.355 ng/mL) cut-off values for predicting unstable glucose homeostasis (CV >36%) in T2DM subjects.

CONCLUSION

Our study suggests that impaired pancreatic β-cell function may be a clinical determining factor of CV of glucose in people with T2DM.

Association of triglyceride-glucose index and stroke recurrence among nondiabetic patients with acute ischemic stroke

Backgroud and purpose

Triglyceride-glucose (TyG) index has been considered a surrogate marker of insulin resistance. We investigated the association between TyG index and stroke recurrence and compared the effectiveness of TyG index with homeostasis model assessment of insulin resistance (HOMA-IR) in predicting stroke recurrence and death in nondiabetic acute ischemic stroke patients.

Methods

Nondiabetic acute ischemic stroke patients from the ACROSS-China (Abnormal Glucose Regulation in Patients with Acute Stroke across China) registry were included. TyG index was performed and classified into four groups by quartiles. The outcomes were stroke recurrence and death within 1 year. The association between TyG index and the risk of stroke recurrence and death were analyzed by Cox regression models. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the prediction of TyG index and HOMA-IR for stroke recurrence and death. Delong test was used for comparing the differences between area under the curve (AUC) of TyG index and HOMA-IR.

Results

Among the 1226 patients included, the median (interquartile range) of TyG index was 5.8 (5.5–6.2). Both the third and fourth quartiles of TyG index were associated with an increased risk of stroke recurrence (adjusted hazard ratio 2.04, 95% confidence interval 1.26–3.31; adjusted hazard ratio 1.86, 95% confidence interval 1.13–3.06). Patients with fourth quartiles of TyG index were associated with a higher mortality risk (adjusted hazard ratio, 2.91; 95% confidence interval, 1.62–2.53). Regarding stroke recurrence within 1 year, the AUC (95% confidence interval) of the ROC curve for the TyG index was similar to that of the HOMA-IR[0.56 (0.52–0.61) vs 0.57 (0.52–0.61); P = 0.93]. Regarding death within 1 year, the AUCs (95% confidence interval) of the ROC curve for the TyG index and HOMA-IR were 0.55 (0.50–0.61) and 0.59 (0.53–0.64), respectively (P = 0.32).

Conclusions

Elevated TyG index was associated with an increased risk of stroke recurrence and death. However, neither of TyG nor HOMA-IR can be a qualified predictor of stroke recurrence and death in nondiabetic acute ischemic stroke patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02588-3.

Decoupled Glucose and Lipid Metabolic Recovery after Viral Clearance in Direct-Acting Antiviral-Treated HCV Patients: A 3-Year Prospective Cohort Study

BACKGROUND/AIM

The recovery pattern of hepatitis C virus (HCV)-associated metabolic alteration after sustained virological response (SVR) following direct-acting antivirals (DAAs) remains elusive.

METHODS

A prospective cohort study of chronic HCV-infected (CHC) patients (n = 415) receiving DAAs (n = 365) was conducted. Metabolic profiles were examined in SVR patients (n = 360) every 3-6 months after therapy and compared with those of sex- and age-matched controls (n = 470).

RESULTS

At baseline, of 415, 168 (40.5%) had insulin resistance (IR). The following were associated: levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs), HCV RNA, fibrosis-4 score, and interferon-λ3-rs12979860 genotype with total cholesterol (TC) levels; and TG levels and BMI with HOMA-IR. Over a 3-year follow-up, in SVR patients, BMI and TC levels and TG/HDL-C ratios increased from baseline, while HOMA-IR trended downward by 72 weeks after therapy and then increased. The increased HDL-C levels began to decrease after 72 weeks after therapy. TC and HOMA-IR were negatively associated with each other until 24 weeks after therapy. Earlier increases in BMI and decreases in HOMA-IR were noted in SVR patients with than in those without baseline IR. Compared with controls, in the subgroup without baseline IR, SVR patients had increased BMI and HOMA-IR levels. Metabolic profiles were similar between SVR patients and controls in the subgroup with baseline IR.

CONCLUSIONS

In SVR patients treated with DAAs, the recovery of altered lipid and glucose metabolism was not coupled until 72-week post-therapy, when HOMA-IR reached its nadir. SVR patients with baseline IR recovered from HCV-associated metabolic alterations earlier than those without baseline IR.

CURING HEPATITIS C WITH THE NEW DIRECT ACTING ANTIVIRALS DID NOT IMPROVE INSULIN RESISTANCE AFTER ONE YEAR

BACKGROUND

Chronic hepatitis C still figures as an important cause of morbidity among the Brazilian population, and is closely associated with metabolic disturbances, including insulin resistance (IR), which can be evaluated by the Homeostatic Model Assessment (HOMA-IR). IR may entail lower sustained virologic response (SVR) on certain therapeutic regimens and faster progression to advanced hepatic fibrosis. With the arrival of the direct acting agents (DAA) in hepatitis C treatment, there is an increased need in observing the impact in patients' IR profile while using such therapies.

OBJECTIVE

- 1) To compare the results of HOMA-IR in patients affected by chronic hepatitis C before treatment with DAA and 12 months after finishing it with SVR. 2) To evaluate the evolution of weight after curing chronic hepatitis C.

METHODS

We included patients older than 18 from two tertiary care in Curitiba - PR, of both sexes, with chronic hepatitis C, treated with DAA, from July 2015 to September 2017. We also evaluated the patients' levels of fasting insulin, fasting glucose and glycated hemoglobin before starting treatment and 12 months after finishing it. We also used epidemiologic data, such as age, sex, hepatic fibrosis degree, body mass index, abdominal circumference, viral genotype and the presence of diabetes mellitus before and after treatment. IR was assessed before and after treatment and calculated by the HOMA-IR score. Insulin resistance was defined by a HOMA-IR greater than 2.5. We excluded patients who lost follow-up, those who did not achieve SRV and those who did not have a laboratory profile. The results of quantitative variables were described by means, medians, and standard deviations. P values <0.05 indicated statistical significance.

RESULTS

We included 75 patients in this study, with a mean age of 55.2 years and 60% of males. Forty-three patients had advanced fibrosis. Twenty one (28%) had a previous diabetes mellitus diagnosis. We identified 31 (41.3%) patients with IR before antiviral treatment, and this number increased to 39 (52%) after 12 months of finishing treatment, according to HOMA-IR. There was no statistic difference between insulin, glucose and HOMA-IR measurements before and after curing hepatitis C. We observed a weight gain in patients shortly after curing hepatitis C, but this did not persist at the end of the study. We also had no significant difference in IR prevalence when viral genotype was concerned.

CONCLUSION

In this study, there was no statistically significant difference between HOMA-IR results in patients before and 12 months after treatment for hepatitis C. Even though patients gained weight after the cure, this was not statistically significant after a year (P=0.131).

Unique Metabolic Features of Adults Discordant for Indices of Insulin Resistance

PURPOSE

Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and Adipose Insulin Resistance index (ADIPO-IR) values are often concordant. In this study we evaluated whether there are groups discordant for HOMA-IR and ADIPOpalmitate-IR and, if so, what are their defining characteristics.

METHODS

The body composition, basal metabolic rate (BMR), fasting plasma lipids, insulin, glucose, and free fatty acid (FFA) palmitate concentrations data of 466 volunteers from previous research studies were abstracted and analyzed. The middle 2 population quartiles for HOMA-IR and Adipose Insulin Resistance index palmitate concentration (ADIPOpalmitate-IR) defined medium HOMA-IR and ADIPOpalmitate-IR (MH and MA), the top and bottom quartiles were defined as high/low HOMA (HH/LH), and high/low ADIPOpalmitate as HA/LA. Because ADIPOpalmitate-IR was significantly greater in women than in men, we established sex-specific quartiles for each index. We identified groups discordant for HOMA-IR and ADIPO-IR (HHMA, LHMA, MHHA, and MHLA).

RESULTS

Body fat and fasting triglycerides (TGs) were significantly greater with higher indices in the concordant groups (HHHA > MHMA > LHLA). MHHA differed from MHLA by visceral fat (P < .01) and fasting TGs (P < .05), whereas HHMA differed (P < .01) from LHMA by BMR. By multivariate regression, the group factor contributed to BMR (P < .01) and visceral fat (P < .05).

CONCLUSIONS

Adults discordant for HOMA-IR and ADIPO-IR have unique features including differences in visceral fat, TGs, and BMR. This suggests different forms of insulin resistance are present, which should be considered when studying insulin resistance in the future.

Fasting Blood Glucose Predicts Incidence of Hypertension Independent of HbA1c Levels and Insulin Resistance in Middle-Aged Japanese: The Saku Study

BACKGROUND

Relationships between blood glucose (BG) levels and insulin action, and incidence of hypertension have not been well known epidemiologically. This study aimed to investigate the association between indices of diabetes and the incidence of hypertension and compare the predictive powers of these indices in middle-aged Japanese.

METHODS

This 5-year cohort study included 2,210 Japanese aged 30-64 years without hypertension. Hazard ratios of high fasting blood glucose (FBG) levels, high post-loaded BG levels, high glycated hemoglobin (HbA1c) levels, insulin resistance (defined by homeostasis model assessment of insulin resistance [HOMA-IR]) and impaired insulin secretion at baseline for the incidence of hypertension were estimated using multivariable-adjusted Cox proportional hazard models. Hypertension was defined as blood pressure ≥ 140/90 mm Hg or receiving antihypertensive treatment.

RESULTS

During the follow-up, 456 participants developed hypertension. After adjustment for HbA1c and HOMA-IR, FBG was independently and significantly associated with hypertension. The hazard ratio of participants with FBG ≥ 7.0 mmol/l was 1.79 compared with those with FBG < 5.6 mmol/l. Even among those with HbA1c < 6.5%, HOMA-IR < 2.5, body mass index < 25 kg/m2, age < 55 years old, blood pressure < 130/80 mm Hg or non- and moderate drinking, the results were similar. High 120-minute BG level and impaired insulin secretion did not increase the risk for hypertension.

CONCLUSIONS

FBG was a predictable index for future incidence of hypertension in middle-aged Japanese men and women. This is the first study comparing predictive powers of indices of diabetes for the incidence of hypertension.

Association of insulin, C-peptide and blood lipid patterns in patients with impaired glucose regulation

BACKGROUND

To investigate any associations between blood glucose (BG) and lipid levels in patients with different glucose tolerance statuses, including type 2 diabetes (T2DM) and impaired glucose regulation (IGR) cases as well as normal glucose tolerance (NGT) individuals.

METHODS

A total of 354 participants were recruited to this study including 174 in the T2DM group, 112 in the IGR group and 68 in the NGT group. We compared BG, insulin and C-peptide (CP), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) serum levels during a 3 h oral glucose tolerance test (OGTT) in the 3 groups.

RESULTS

Basic overall HbA1c serum concentration percentages were 5.52, 6.33 and 9.76% for the NTG, IGR and T2DM cases. During the OGTT, insulin secretion in the IGR group was almost double that of the T2DM group. CP levels were highest in the IGR patients and OGTT related BG concentrations were highest in the T2DM group followed by IGR, but in the IGR group hyperglycemia was less pronounced than in T2DM patients (P <  0.001). Compared to the NGT group, TC, TG and LDL-C serum concentrations were significantly higher (P ≤ 0.001) and HDL-C concentrations were significantly lower (P ≤ 0.001) in IGR and T2DM cases compared to the NTG group.

CONCLUSIONS

IGR led to similar unfavorable blood lipid patterns compared with T2DM patients and an imbalance of insulin and CP serum concentrations during an OGTT.

Triglyceride Glucose Index Is Superior to the Homeostasis Model Assessment of Insulin Resistance for Predicting Nonalcoholic Fatty Liver Disease in Korean Adults

BACKGROUND

Recently, the triglyceride glucose (TyG) index has been considered a surrogate marker of insulin resistance which is a well-known pathogenic factor in nonalcoholic fatty liver disease (NAFLD). However, few studies have investigated the relationship between the TyG index and NAFLD. Thus, we investigated the relationship between the TyG index and NAFLD and the effectiveness of the TyG index compared with the homeostasis model assessment of insulin resistance (HOMA-IR) in identifying NAFLD in Korean adults.

METHODS

Participants of 4,986 who underwent ultrasonography in a health promotion center were enrolled. The TyG index was calculated as ln [fasting triglycerides (mg/dL)×fasting glucose (mg/dL)/2], and HOMA-IR was estimated. NAFLD was diagnosed by ultrasonography.

RESULTS

Significant differences were observed in metabolic parameters among the quartiles of the TyG index. The prevalence of NAFLD significantly increased with increment in the TyG index. After adjusting for multiple risk factors, a logistic regression analysis was performed. When the highest and lowest quartiles of the TyG index and HOMA-IR were compared, the odds ratios for the prevalence of NAFLD were 2.94 and 1.93 (95% confidence interval, 2.32 to 3.72 and 1.43 to 2.61; both P for trend <0.01), respectively. According to the receiver operating characteristic analysis, the TyG index was superior to HOMA-IR in predicting NAFLD.

CONCLUSION

The TyG index and prevalence of NAFLD were significantly related and the TyG index was superior to HOMA-IR in predicting NAFLD in Korean adults.

Acanthosis nigricans in the knuckles: An early, accessible, straightforward, and sensitive clinical tool to predict insulin resistance

Any clinical/biochemical marker revealing obesity or diabetes before their appearance is valuable. Insulin resistance (IR) is present in both disorders many years before occurrence. Accordingly, we determined whether acanthosis nigricans (AN) in the knuckles is associated to higher insulin and homeostasis model assessment for estimated insulin resistance (HOMA-IR) index values, and assessed the influence of body-mass index (BMI) and the diagnostic performance of AN in the knuckles to detect IR. In this cross-sectional controlled study, we included men or women, 18 to 23 years old, with or without AN in the knuckles. In 149 cases with AN in the knuckles and 145 controls, fasting insulin was higher in cases (13.45 µU/mL ± 7.8 vs. 8.59 µU/mL ± 3.63, P < .001, respectively). Mean HOMA-IR index was also higher (2.86 ± 1.68 vs. 1.78 ± 0.77, P < .001). A significant increase in fasting insulin and HOMA-IR values between and within BMI groups from normal through obese category was identified in controls and cases. By multivariate regression analysis, cases with normal BMI were significantly associated to a HOMA-IR ≥2.5 (OR = 3.09, CI95% = 1.75-5.48, P = .001). A model of AN in the knuckles, normal BMI, and increased waist circumference allowed identifying 2 out of 3 cases with HOMA-IR index ≥2.5. AN in the knuckles could be addressed with two aims: as an easy, accessible, and costless diagnostic tool suggesting hyperinsulinemia secondary to IR, and, an early marker of IR even in the absence of overweight or obesity.

Triglyceride Glucose-Body Mass Index Is a Simple and Clinically Useful Surrogate Marker for Insulin Resistance in Nondiabetic Individuals

Background

Insulin resistance (IR) and the consequences of compensatory hyperinsulinemia are pathogenic factors for a set of metabolic abnormalities, which contribute to the development of diabetes mellitus and cardiovascular diseases. We compared traditional lipid levels and ratios and combined them with fasting plasma glucose (FPG) levels or adiposity status for determining their efficiency as independent risk factors for IR.

Methods

We enrolled 511 Taiwanese individuals for the analysis. The clinical usefulness of various parameters—such as traditional lipid levels and ratios; visceral adiposity indicators, visceral adiposity index (VAI), and lipid accumulation product (LAP); the product of triglyceride (TG) and FPG (the TyG index); TyG with adiposity status (TyG-body mass index [BMI]) and TyG-waist circumference index [WC]); and adipokine levels and ratios—was analyzed to identify IR.

Results

For all lipid ratios, the TG/high-density lipoprotein cholesterol (HDL-C) ratio had the highest additional percentage of variation in the homeostasis model assessment of insulin resistance (HOMA-IR; 7.0% in total); for all variables of interest, TyG-BMI and leptin-adiponectin ratio (LAR) were strongly associated with HOMA-IR, with 16.6% and 23.2% of variability, respectively. A logistic regression analysis revealed similar patterns. A receiver operating characteristic (ROC) curve analysis indicated that TG/HDL-C was a more efficient IR discriminator than other lipid variables or ratios. The area under the ROC curve (AUC) for VAI (0.734) and TyG (0.708) was larger than that for TG/HDL-C (0.707). TyG-BMI and LAR had the largest AUC (0.801 and 0.801, respectively).

Conclusion

TyG-BMI is a simple, powerful, and clinically useful surrogate marker for early identification of IR.

Myeloperoxidase is associated with insulin resistance and inflammation in overweight subjects with first-degree relatives with type 2 diabetes mellitus

BACKGROUND

Family history of type 2 diabetes mellitus (T2DM) is one of risk factors for that in future a subject can develop diabetes. Insulin resistance (IR) is important in the pathogenesis of T2DM. There is evidence that oxidative stress plays an important role in the etiology and/or progression of diabetes. Myeloperoxidase (MPO) participates in developing of inflammation. The objective was to investigate if MPO is associated with IR and inflammation in individuals with first-degree relatives of T2DM.

METHODS

Cross-sectional study in 84 overweight individuals with family history of T2DM divided in two groups according to IR, group with IR (homeostasis model assessment [HOMA] ≥2.5; n=43) and control group (CG; HOMA <2.5; n=41). Complete clinical history and a venous blood sample were collected for measuring glucose and lipids profile, insulin, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), MPO, glutathione reductase (GRd), glutathione peroxidase, and superoxide dismutase.

RESULTS

MPO, TNF-α, and IL-6 were higher in patients with IR than in CG (MPO: 308.35 [190.85 to 445.42] vs. 177.35 [104.50 to 279.85], P=0.0001; TNF-α: 13.46 [10.58 to 18.88] vs. 9.39 [7.53 to 11.25], P=0.0001; IL-6: 32.93 [24.93 to 38.27] vs. 15.60 [12.93 to 26.27]; P=0.0001, respectively). MPO was associated with IR (rho de Spearman=0.362, P=0.001). In the analysis of lineal regression, MPO predicts IR (β, 0.263; t, 2.520; P=0.014). In the univariate analysis, MPO had an odds ratio of 9.880 for risk of IR (95% confidence interval, 2.647 to 36.879).

CONCLUSION

MPO had relation with IR and inflammation parameters in overweight subjects with first-degree relatives of T2DM. We need studies on a casual relationship and molecular mechanisms among the increased serum MPO levels, inflammation markers, and IR.

Relationship and factors responsible for regulating fasting and post-challenge plasma glucose levels in the early stage development of type 2 diabetes mellitus

AIMS/INTRODUCTION

Elevation of 2-h plasma glucose (2-h PG) levels keeps step with fasting plasma glucose (FPG) levels elevation, but some individuals show dominant elevation of 2-h PG and others FPG. We analyzed dependent and independent relationships between 2-h PG and FPG, and investigated the factors regulating 2-h PG and FPG.

MATERIALS AND METHODS

In 1,657 Japanese participants who underwent a 75-g oral glucose tolerance test at the initial examination for a medical check-up, we carried out simple linear regression analysis between 2-h PG and FPG levels on the three patterns of independent variables. We divided the participants into two subgroups: the 2-h PG-side group and the FPG-side from the regression line, and examined the relationships between 2-h PG-FPG and factors responsible for elevation of plasma glucose levels.

RESULTS

There was a significant positive correlation between 2-h PG and FPG levels. The regression line of both 2-h PG and FPG as independent variables was in accordance with the regression line of 2-h PG as an independent variable and FPG as a dependent variable. In 2-h PG-side group, age was the independent factor affecting 2-h PG in addition to insulinogenic index and insulin sensitivity index (ISI composite). In the FPG-side group, triglyceride was the independent factor affecting FPG in addition to insulinogenic index and ISI composite.

CONCLUSIONS

Two-hour PG was an independent predictor of FPG. In addition to the importance of decreased insulin secretion and insulin sensitivity, age was the strong factor to elevate 2-h PG levels in the 2-h PG-side group and triglyceride was the strong factor to elevate FPG levels in the FPG-side group in the early stage of development of type 2 diabetes.

Regression models for log-normal data: comparing different methods for quantifying the association between abdominal adiposity and biomarkers of inflammation and insulin resistance

We compared six methods for regression on log-normal heteroscedastic data with respect to the estimated associations with explanatory factors (bias and standard error) and the estimated expected outcome (bias and confidence interval). Method comparisons were based on results from a simulation study, and also the estimation of the association between abdominal adiposity and two biomarkers; C-Reactive Protein (CRP) (inflammation marker,) and Insulin Resistance (HOMA-IR) (marker of insulin resistance). Five of the methods provide unbiased estimates of the associations and the expected outcome; two of them provide confidence intervals with correct coverage.

Improvement of glycated hemoglobin in Japanese subjects with type 2 diabetes by resolution of periodontal inflammation using adjunct topical antibiotics: results from the Hiroshima Study

AIMS

Periodontal treatment reduces glycated hemoglobin (HbA1) in subjects with type 2 diabetes, although effective strategy for different severities of periodontitis remains unclear. We hypothesized that resolution of periodontitis-induced inflammation by the therapy combined with antibiotics may have beneficial effects on the glycemic control of diabetes.

METHODS

A total of 523 subjects with type 2 diabetes were screened for periodontal disease. Of these, 160 subjects who visited dentists were divided into two groups according to high-sensitivity c-reactive protein (hsCRP) level: >500 ng/ml and <500 ng/ml. The group with hsCRP over 500 ng/ml was further sub-divided into two groups according to treatment strategy: topical application of antibiotics combined with conventional mechanical debridement (group A), and debridement alone (B). Subjects with hsCRP below 500 ng/ml were sub-divided similarly (C: combination therapy; D: debridement alone). hsCRP was measured after 1 month and changes of HbA1c after 3 months. These parameters were also measured in control subjects (N=118) who did not visit dentists (E: initial hsCRP>500 ng/ml; F: hsCRP<500 ng/ml).

RESULTS

A multiple comparison by ANOVA revealed that only group A showed a significant reduction in HbA1c over time (P<0.001). Multivariable analyses revealed elevated hsCRP and the combination treatment with antibiotics were two independent variables influencing the decrease of HbA1c over the study (P<0.01 and P<0.001, respectively).

CONCLUSIONS

In subjects with type 2 diabetes and periodontitis-induced mild inflammation (hsCRP>500 ng/ml), treatment to reduce hsCRP using antibiotics is recommended.

Nutrient intake, serum lipids and iron status of colligiate rugby players

Background

There are two main playing positions in rugby (backs and forwards), which demonstrate different exercise patterns, roles, and physical characteristics. The purpose of this study was: 1) to collect baseline data on nutrient intake in order to advise the athletes about nutrition practices that might enhance performance, and 2) to compare serum lipids, lipoproteins, apolipoproteins (apo), lecithin:cholesterol acyltransferase (LCAT) activity, and iron status of forwards and backs.

Methods

The sporting group was divided into 18 forwards and 16 backs and were compared with 26 sedentary controls. Dietary information was obtained with a food frequency questionnaire.

Results

There were significant differences among the three groups. The forwards had the highest body weight, body mass index, percentage of body fat (calculated by sum of four skinfold thicknesses), as well as the highest lean body mass, followed by the backs and the control group. The mean carbohydrate intake was marginal and protein intake was lower than the respective recommended targets in all three groups. The mean intakes of calcium, magnesium, and vitamins A, B₁, B₂, and C were lower than the respective Japanese recommended dietary allowances or adequate dietary intakes for the rugby players. The forwards had significantly lower high-density lipoprotein cholesterol (HDL-C) and HDL₂-C than the backs and had significantly higher apo B and LCAT activity than the controls. The backs showed significantly higher HDL-C, HDL₃-C, low-density lipoprotein cholesterol, and apo A-I, and LCAT activity than the controls. Four forwards (22%), five backs (31%), and three controls (12%) had hemolysis. None of the rugby players had anemia or iron depletion.

Conclusion

The findings of our study indicate that as the athletes increased their carbohydrate and protein intake, their performance and lean body mass increased. Further, to increase mineral and vitamin intakes, we recommended athletes increase their consumption of green and other vegetables, milk and dairy products, and fruits. The forwards showed more atherogenic lipid profiles than the backs, whereas the backs showed not only anti-atherogenic lipid profile, but also showed more atherogenic lipid profile relative to the control group. Additionally, our study showed none of the rugby players experienced anemia and/or iron depletion.

Physical activity and blood lipids and lipoproteins in dialysis patients

The relationship between physical activity and blood lipids and lipoproteins in dialysis patients is reviewed in the context of the potentially confounding factors such as nutritional intake, cigarette smoking, obesity, alcohol intake, and physical activity levels in the general population and additional confounding factors such as mode of dialysis and diabetes in dialysis patients. The known associations in the general population of physical activity with high-density-lipoprotein cholesterol subfractions and apolipoprotein A-I are more pronounced in hemodialysis patients than in peritoneal dialysis patients even after adjusting for these confounding factors. Examining studies on the effects of physical activity on blood lipids and lipoproteins, the most consistent observation is the noted decrease in triglycerides and increase in high-density-lipoprotein cholesterol and insulin sensitivity in hemodialysis patients. The changes in lipids and lipoproteins in hemodialysis patients could be caused by changes in activity levels of lipoprotein lipase, insulin sensitivity, and/or glucose metabolism. Future research investigating the relationship between physical activity and blood lipids and lipoproteins in dialysis patients should direct research towards the underlying mechanisms for changes in blood lipids and lipoproteins.

Atherosclerotic Risk Factors and Premature Atherosclerosis in Acromegaly Before and After 48 Months of Octreotide-LAR Treatment

We studied premature atherosclerosis with carotid Doppler ultrasonography in active acromegaly before and after treatment. Patients (n = 27) with active acromegaly and 12 age-, gender-, and body mass index-matched healthy individuals were included in the study. Carotid intima–media thickness was decreased significantly in the inactive group after treatment (median: 0.6 mm, interquartile range [IQR]: 0.55-0.80]) when compared with the active group (median: 0.9 mm [IQR: 0.75-1.15], P < .0001), but there was no significant difference between the inactive and control groups. There was a correlation between homeostasis model of assessment–insulin resistance ( P = .01, r = .41) and growth hormone (GH; P < .0001, r = .46). In conclusion, premature atherosclerosis was demonstrated in active acromegaly patients probably as a consequence of insulin resistance and direct vascular effects of GH and/or insulin-like growth factor 1.

Periodontal disease and hypertriglyceridemia in Japanese subjects: potential association with enhanced lipolysis

Although periodontal disease may be associated with increased risk for atherosclerosis, the mechanism by which the disease causes atherosclerosis is still unknown. The candidates contributing to atherosclerosis in periodontal disease include low-grade inflammation such as C-reactive protein (CRP) and insulin resistance. A previous study demonstrated that periodontal therapy leads to an improvement in CRP as well as insulin resistance, indicating the relationship between periodontal disease and low-grade inflammation or insulin resistance. On the other hand, we previously demonstrated that serum triglyceride (TG) per se is independently associated with CRP or insulin resistance in Japanese populations with a body mass index (BMI) of 21.5 to 27.0 (midrange BMI). To the best of our knowledge, however, the relationship between periodontal disease and serum TG is not fully clarified. The first aim of the present study is to investigate whether periodontal disease is associated with serum TG in Japanese subjects with midrange BMI. If so, another aim of the study is to determine which mechanism is responsible for the association between periodontal disease and serum TG in these subjects. We have performed a periodontal examination in the Ogaki metabolic syndrome medical examination. One hundred sixty-two participants from 40 to 74 years old (56 men and 106 women; mean age, 66.43 ± 6.25 years) were enrolled in the study. Besides medical examination, oral panoramic radiograph was taken for all participants. Average bone score was also calculated. Periodontal bone destruction increased according to the age of the participants (r = 0.227, P < .004, Spearman correlation coefficient). Periodontal bone destruction was also associated with serum TG levels (r = 0.299, P = .000). This association was more evident in subjects with midrange BMI (r = 0.332, P < .001). In subjects with midrange BMI, TG was not correlated with BMI or waste circumstances. Furthermore, TG was not associated with age itself in the midrange BMI group. We then investigated the lipolytic activity of endotoxin in cocultures of adipocytes and macrophages. Low-dose lipopolysaccharide dose-dependently increased lipolytic activity in cocultures, and this activity was neutralized by anti-tumor necrosis factor α neutralizing antibodies. These results suggest that periodontal infection, especially bacterial endotoxinemia, is associated with enhanced lipolysis and subsequent up-regulation of circulating TG in Japanese with midrange BMI.

A positive association between homeostasis model assessment of insulin resistance score and the Trp64Arg polymorphism of the β3-Adrenergic receptor gene in schizophrenia patients in Taiwan

OBJECTIVE

To investigate the possible association between the Trp64Arg polymorphism of the β3-adrenergic receptor gene and the homeostasis model assessment of insulin resistance (HOMA-IR) index in schizophrenia patients in Taiwan.

METHOD

A total of 203 inpatients who met DSM-IV diagnostic criteria for schizophrenia were recruited from a psychiatry center in Taiwan from September 2002 to August 2003. All patients had been treated with antipsychotics for at least 6 months. The genotyping of the Trp64Arg polymorphism of the β3-adrenergic receptor gene was done by the polymerase chain reaction-restriction fragment length polymorphism method with the restriction enzyme MvaI. The HOMA-IR index was used to indicate the degree of insulin resistance.

RESULTS

After adjusting for sex, age, and body mass index status, the association between the HOMA-IR index and the Trp64Arg polymorphism of the β3-adrenergic receptor gene was still positive (regression coefficient = -0.65, P = .033).

CONCLUSIONS

The polymorphism of the β3-adrenergic receptor gene may be related to the development of insulin resistance in chronic schizophrenia patients in Taiwan.

Analysis of factors influencing pancreatic beta-cell function in Japanese patients with type 2 diabetes: association with body mass index and duration of diabetic exposure

AIMS

To elucidate the clinical factors affecting beta-cell function, serum C-peptide immunoreactivity (CPR) levels of patients with type 2 diabetes were analyzed.

METHODS

Seven hundred Japanese patients with type 2 diabetes were enrolled. beta-Cell function was evaluated by fasting CPR (FCPR), 6 min after intravenous injection of 1mg glucagon (CPR-6 min), and the increment of CPR (DeltaCPR). Simple regression analysis between FCPR, CPR-6 min, and DeltaCPR and measures of variables and stepwise multiple regression analysis were carried out.

RESULTS

Years from diagnosis and BMI were the major independent variables predicting beta-cell function. Years from diagnosis was negatively correlated with CPR-6 min (P<0.0001, r=-0.271), and decrease in CPR-6 min was 0.050 ng/(ml year). BMI was positively correlated with CPR-6 min (P<0.0001, r=0.369). When subjects were divided according to BMI, the decrease in CPR-6 min per year in the high-BMI group (0.068 ng/(ml year)) was greater than that in the low-BMI group (0.035 ng/(ml year)).

CONCLUSION

A linear decline in endogenous insulin secretion over more than several decades of diabetes was confirmed by this cross-sectional study. The duration of diabetes exposure and BMI are thus major factors in beta-cell function in Japanese patients with type 2 diabetes.

High dose flaxseed oil supplementation may affect fasting blood serum glucose management in human type 2 diabetics

Type 2 diabetes is characterized partially by elevated fasting blood serum glucose and insulin concentrations and the percentage of hemoglobin as HbA1c. It was hypothesized that each of blood glucose and its co-factors insulin and HbA1c and would show a more favorable profile as the result of flaxseed oil supplementation. Patients were recruited at random from a population pool responding to a recruitment advertisement in the local newspaper and 2 area physicians. Completing the trial were 10 flaxseed oil males, 8 flaxseed oil females, 8 safflower (placebo) oil males and 6 safflower oil females. Patients visited on two pre-treatment occasions each three months apart (visits 1 and 2). At visit 2 subjects were randomly assigned in double blind fashion and in equal gender numbers to take flaxseed oil or safflower oil for three further months until visit 3. Oil consumption in both groups was approximately 10 g/d. ALA intake in the intervention group was approximately 5.5 g/d. Power was 0.80 to see a difference of 1 mmol of glucose /L using 12 subjects per group with a p < 0.05. Flaxseed oil had no impact on fasting blood serum glucose, insulin or HbA1c levels. It is concluded that high doses of flaxseed oil have no effect on glycemic control in type 2 diabetics.

Insulin-resistance (IR) in older age

A study pool of 1549 normoglycemic elderly in the age range of 65-84 years, taken from the epidemiological Italian Longitudinal Study on Aging (ILSA), was constructed. The values of IR, %B and %S were analyzed using the homeostasis assessment model-2 (HOMA-2). In the subjects displaying normal values of several studied parameters such as the arterial blood pressure, total cholesterol (T-CH), high-density lipoproteins (HDL), and triglycerides (TG), the values of IR, %B and %S remained in the normal ranges (in average 1.66+/-1.11, 133.64+/-63.56 and 91.12+/-79.75, respectively). These latter values increase in the subjects who had altered values of the studied basic parameters listed above, and the increases were higher with the higher frequency of the altered parameters. The results seem to confirm the possibility that the normoglycemic elderly subjects having a compensatory insulin hypersecretion against the IR, may develop a type 2 diabetes or a metabolic syndrome.

Factors responsible for age-related elevation in fasting plasma glucose: a cross-sectional study in Japanese men

To evaluate the factors associated with age-related increase in fasting plasma glucose (FPG) in Japanese men with normal fasting glucose, we measured FPG, fasting immunoreactive insulin, glycated hemoglobin, total cholesterol, triglyceride, and high-density lipoprotein cholesterol levels in health check examinees. Subjects with FPG less than 6.1 mmol/L together with glycated hemoglobin less than 5.6% were enrolled in the study. The homeostasis model assessment of insulin resistance (HOMA-IR) and HOMA-beta were used as the indices of insulin sensitivity and insulin secretion, respectively. Fasting plasma glucose increased significantly with age (r = 0.30, P < .0001), and HOMA-beta decreased significantly with age (r = 0.24, P < .0001). The HOMA-IR had no significant relation with age (r = 0.06, not significant), whereas body mass index and serum triglyceride were associated with HOMA-IR (r = 0.49, P < .0001 and r = 0.33, P < .0001, respectively). Thus, in Japanese male subjects with normal fasting glucose, it is suggested that the FPG increment with age is associated with decreased beta-cell function rather than with insulin resistance. Further analyses were performed by comparing 3 groups: low FPG (FPG <5.0 mmol/L), high FPG (5.0 < or = FPG < 5.6 mmol/L), and mild impairment of fasting glycemia (mild IFG) (5.6 < or = FPG < 6.1 mmol/L). The insulin levels in mild IFG and high FPG were significantly higher than in low FPG (P < .001), but those in mild IFG were similar to those in high FPG. Analysis of the 3 subgroups revealed that, whereas insulin sensitivity was impaired more in high FPG, there was little compensatory increase in insulin in mild IFG, suggesting that beta-cell function is already deteriorated when the FPG level is greater than 5.6 mmol/L.

The lean patient with type 2 diabetes: characteristics and therapy challenge

Although obesity is a key component of type 2 diabetes, particularly in the Western world, many patients are not overweight by traditional criteria. However, evolving definitions of overweight and obesity and an appreciation of the factors influencing obesity in type 2 diabetes are redefining the concept of the non-overweight (lean) patient. Several factors need to be considered, including body mass index, waist circumference and ethnicity when considering whether a patient is lean, and appropriate obesity threshold values need to be used. Lean patients are more likely to be older at diagnosis, possibly have an immune component and may have a tendency towards certain pathophysiological characteristics, notably less insulin resistance and poorer insulin secretory capacity. However, pathophysiological heterogeneity may also be greater among lean patients and this imparts a particular challenge to therapy. An early focus on multiple metabolic defects may provide an optimal approach to treating the lean patient with type 2 diabetes in clinical practice, and combination therapy that addresses both insulin secretory dysfunction and insulin resistance would seem a rational approach.

Factors responsible for the evolution of insulin resistance in Japanese type 2 diabetic patients: association with atherosclerosis

Type 2 diabetes is a heterogeneous syndrome characterized by defective insulin secretion and/or insulin resistance. In distinct from Caucasian populations, Japanese type 2 diabetic patients are divided into two categories: one with insulin resistance and the other with normal insulin sensitivity. This unique feature allows us to explore the factors responsible for the evolution of insulin resistance in Japanese type 2 diabetic patients. In this article, we describe the factors responsible for insulin resistance in Japanese type 2 diabetic patients and discuss the relationships between these factors and atherosclerosis. Japanese type 2 diabetic patients with insulin resistance had significantly higher concentrations of triglyceride, remnant-like particle cholesterol, subcutaneous and visceral abdominal fat areas, leptin, high sensitive C-reactive protein (hs-CRP), and soluble E-selectin and lower concentration of adiponectin when compared to those with normal insulin sensitivity. There were, however, no significant difference in tumor necrosis factor (TNF)-alpha and soluble TNF receptors between the two groups. Serum triglyceride was positively correlated to visceral abdominal fat area, while serum leptin was positively correlated with subcutaneous abdominal fat area. In contrast, serum adiponectin was negatively correlated to visceral abdominal fat area. High sensitive CRP was positively correlated to BMI, triglyceride, and leptin, but was negatively correlated to adiponectin. Tumor necrosis factor-alpha and soluble TNF receptors, however, were not associated with any of these factors. Thus, it may be hypothesized that Japanese type 2 diabetic patients are divided into two categories: one with normal insulin sensitivity and the other with insulin resistance. The former group has a low cardiovascular risk factor, whereas the latter one has a markedly increased cardiovascular disease risk factor. Furthermore, abdominal fat related insulin resistance seems to be associated with insulin resistance in Japanese type 2 diabetic patients. In this section, we would like to focus on the factors contributing to insulin resistance and discuss the association of these factors with atherosclerosis in Japanese type 2 diabetic patients.

Plasma triglycerides are not related to tissue lipids and insulin sensitivity in elderly following PPAR-alpha agonist treatment

Increases in plasma lipids, tissue triglycerides and decreases in mitochondrial function have been linked to insulin resistance and aging. In animals, peroxisome proliferator-activated receptor-alpha (PPAR-alpha) agonists decrease plasma lipids, intramyocellular fat (IMCL) and liver fat (LFAT) and improve mitochondrial beta-oxidative function and insulin sensitivity, but the effects in elderly were not known. Insulin sensitivity was assessed with a 2-h oral glucose tolerance test, magnetic resonance spectroscopy was used to asses IMCL, LFAT and plasma lipids were measured before and after 6, 11 and 61 days of PPAR-alpha agonist (fenofibrate) administration in 19 elderly (age 70+/-1 years) volunteers. Volunteers were stratified into healthy (N=7) and insulin resistant (N=12) groups. The baseline insulin sensitivity index (8.1+/-1.2 vs. 3.8+/-0.5, healthy vs. insulin resistant; P<0.001) was significantly higher in the healthy group. Fenofibrate treatment induced significant reductions in plasma triglycerides (P<0.001) and total cholesterol (P<0.001) in both groups. Nonetheless, neither fasted free fatty acids, glucose, insulin, nor insulin sensitivity improved in either group (day 1 vs. day 61, 8.1+/-1.2 vs. 8.1+/-0.9, healthy; and 3.8+/-0.5 vs. 4.2+/-0.05, insulin resistant). Furthermore, there was no change in IMCL or LFAT. These results indicate that whereas fenofibrate significantly lowers plasma lipids it neither affects insulin sensitivity nor intracellular lipids in elderly.

Metabolic syndrome, insulin resistance, and atherosclerosis in Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationships between metabolic syndrome and atherosclerosis in 57 Japanese type 2 diabetic patients. Metabolic syndrome was diagnosed based on the criteria raised by the Japan Internal Medicine Society. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment. Ultrasonographically measured carotid atherosclerosis, brachial-ankle pulse wave velocity (ba-PWV), and ankle brachial index (ABI) were used to assess the degree of atherosclerosis. Of 57 patients, 25 were diagnosed as having metabolic syndrome. The patients with metabolic syndrome had significantly higher levels of waist circumference, insulin, insulin resistance index of homeostasis model assessment, systolic and diastolic blood pressures, and serum triglycerides, and lower concentrations of adiponectin. However, there was no significant difference in age, sex, glycosylated hemoglobin (hemoglobin A1c), fasting glucose, leptin, and tumor necrosis factor system activities including tumor necrosis factor alpha between the 2 groups. Furthermore, no significant difference was observed in the degree of carotid atherosclerosis (intimal-medial thickness in plaque-free segments: 0.72+/-0.03 vs 0.72+/-0.02 mm, P=.435; carotid stenosis in plaque segments: 6.6%+/-3.0% vs 6.6%+/-1.7%, P=.497), ba-PWV (1676+/-56 vs 1654+/-44, P=.380), and ABI (1.16+/-0.01 vs 1.15+/-0.01, P=.245) between the 2 groups. From these results, it can be suggested that metabolic syndrome, an insulin-resistant state, is not associated with carotid atherosclerosis, ba-PWV, or ABI in Japanese type 2 diabetic patients.

Soluble tumor necrosis factor receptor 2 is independently associated with pulse wave velocity in nonobese Japanese patients with type 2 diabetes mellitus

The aim of the present study was to investigate the factors contributing to pulse wave velocity (PWV) in patients with type 2 diabetes mellitus. We focused on tumor necrosis factor (TNF) including soluble TNF receptors (sTNF-R1, sTNF-R2) in this study because TNF seems to be associated with the progression of atherosclerosis and because the relationships between PWV and TNF were not yet examined in type 2 diabetic patients. Univariate regression analyses showed that PWV was positively correlated with age (r=0.492, P<.001), diabetes duration (r=0.251, P=.021), systolic (r=.595, P<.001) and diastolic (r=0.248, P=.022) blood pressure, antihypertensive medication (r=0.268, P=.013), and the concentrations of sTNF-R1 (r=0.354, P=.001) and sTNF-R2 (r=0.415, P<.001). Although there was a positive correlation between TNF-alpha and sTNF-R1 (r=0.382, P<.001) or sTNF-R2 (r=0.394, P<.001), TNF-alpha was not associated with PWV. Other variables including gender were not associated with PWV. Multiple regression analyses showed that PWV was independently predicted by the level of age (F=15.1), systolic blood pressure (F=31.6), and sTNF-R2 (F=5.2), which explained 49.2% of the variability of PWV. From these results, it can be concluded that serum soluble TNF receptor is an important independent factor associated with aortic PWV in type 2 diabetic patients.

Interleukin 6, adiponectin, leptin, and insulin resistance in nonobese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationships between interleukin 6 (IL-6) and insulin resistance, serum leptin, serum adiponectin, or serum lipids including triglycerides in 98 nonobese Japanese type 2 diabetic patients. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Serum IL-6 concentration was negatively correlated to high-density lipoprotein cholesterol (r = -0.295, P = .004), but was not associated with HOMA-IR (r = 0.016, P = .871), body mass index (BMI) (r = 0.090, P = .375), systolic (r = 0.169, P = .116) and diastolic (r = -0.061, P = .570) blood pressures, leptin (r = 0.062, P = .544), and adiponectin (r = -0.020, P = .841) in these patients. In contrast, serum leptin level was positively correlated to HOMA-IR (r = 0.291, P = .004), BMI (r = 0.338, P < .001), and systolic blood pressure (r = 0.241, P = .025). Serum adiponectin level was negatively correlated to HOMA-IR (r = -0.288, P = .005), BMI (r = -0.308, P = .002), diastolic blood pressure (r = -0.269, P = .012), and triglycerides (r = -0.338, P < .001), and positively correlated to high-density lipoprotein cholesterol (r = 0.300, P = .003) in our patients. From these results, it can be suggested that fasting serum IL-6 is not a major factor responsible for the evolution of insulin resistance in nonobese Japanese type 2 diabetic patients.

Three measures of tumor necrosis factor alpha activity and insulin resistance in nonobese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationship between insulin resistance and tumor necrosis factor alpha (TNF-alpha) as well as soluble TNF receptors (sTNF-R), body mass index (BMI), leptin, adiponectin, and serum lipid profile including triglycerides in nonobese Japanese patients with type 2 diabetes. A total of 88 nonobese Japanese type 2 diabetic patients were studied. The duration of diabetes was 11.0 +/- 0.8 years. In conjunction with BMI, glycosylated hemoglobin (HbA1c), fasting concentrations of plasma glucose, serum lipids (triglycerides, high-density lipoprotein cholesterol, and total cholesterol), serum leptin, serum adiponectin, serum TNF-alpha, and soluble TNF receptors (sTNF-R1 and sTNF-R2) were also measured. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment. Insulin resistance was positively correlated with BMI, triglycerides, leptin, and total cholesterol and negatively correlated with adiponectin and high-density lipoprotein cholesterol. In contrast, insulin resistance was not associated with TNF-alpha, nor sTNF-R (sTNF-R1 and sTNF-R2) in our diabetic patients. There was no significant relationship between the 3 measures of TNF-alpha system (TNF-alpha, sTNF-R1, and sTNF-R2) and BMI, serum triglycerides, leptin, or adiponectin in these patients. From these results, it can be concluded that peripheral levels of TNF-alpha system activity are not a major factor responsible for insulin resistance in nonobese Japanese type 2 diabetic patients.

Effects of Nurse-coordinated Intervention on Patients With Type 2 Diabetes in Korea

This study investigated the effects of a nurse-coordinated intervention on patients with type 2 diabetes in Korea. Fifteen patients were randomly assigned to an intervention group and 10 to a control group. The intervention was implemented for 12 weeks by telephone. Patients in the intervention group had a mean decrease of 1.2% in glycosylated hemoglobin (HbA(1C)) levels and those in the control group had a mean increase of 0.5%. Patients' satisfaction with care was higher in the intervention group than in the control group after the intervention. These findings indicated that the nurse-coordinated intervention could improve HbA(1C) levels and satisfaction with care in patients with type 2 diabetes in Korea.

Soluble E-selectin, leptin, triglycerides, and insulin resistance in nonobese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationships between insulin resistance and soluble E-selectin, body mass index (BMI), leptin, and serum lipid profile including triglycerides in nonobese Japanese type 2 diabetic patients. A total of 97 nonobese Japanese type 2 diabetic patients aged 43 to 84 years were examined. The duration of diabetes was 11.2 +/- 0.8 years. In conjunction with BMI and fasting concentrations of plasma glucose, serum lipids (triglycerides, total cholesterol, and high-density lipoprotein cholesterol) and serum insulin, soluble E-selectin, and leptin were also measured. The low-density lipoprotein (LDL) cholesterol level was calculated using the Friedewald formula. Insulin resistance was estimated by the homeostasis model assessment. The subjects were divided into 2 groups according to the value of insulin resistance estimated by the homeostasis model assessment. Values greater than 2.5 were indicative of the insulin-resistant state, and values less than 2.5 were indicative of the insulin-sensitive state. The insulin-resistant group had significantly higher levels of E-selectin, leptin, triglycerides, total and LDL cholesterol, and diastolic blood pressure as compared with the insulin-sensitive group. There was, however, no significant difference in age, sex, diabetes duration, BMI, systolic blood pressure, HbA1c, and high-density lipoprotein cholesterol between the 2 groups. Univariate regression analysis showed that insulin resistance was positively correlated to E-selectin (r = 0.305, P = .003), BMI (r = 0.283, P = .006), leptin (r = 0.296, P = .004), HbA1c (r = 0.241, P = .018), serum triglycerides (r = 0.385, P < .001), serum total (r = 0.240, P = .019) and LDL cholesterol (r = 0.254, P = .013) levels, and systolic (r = 0.247, P = .024) and diastolic (r = 0.305, P = .006) blood pressure. Multiple regression analyses showed that insulin resistance was independently predicted by serum E-selectin (F = 18.4), serum leptin (F = 14.0) and serum triglycerides (F = 20.0) levels, which explained 45.0% of the variability of insulin resistance. From these results, it can be concluded that in conjunction with serum triglycerides and serum leptin, serum E-selectin is another important independent factor associated with insulin resistance in nonobese Japanese type 2 diabetic patients.

Insulin resistance increases circulating malondialdehyde-modified LDL and impairs endothelial function in healthy young men

BACKGROUND

Endothelial dysfunction is regarded as an early feature of atherosclerosis. Both LDL oxidation and insulin resistance play important roles in the pathogenesis of atherosclerosis. Recent studies have demonstrated a significant association between oxidized LDL and insulin resistance.

METHODS

We investigated relationships between insulin resistance, circulating malondialdehyde-modified (MDA)-LDL, and endothelial function in 36 healthy young men. Insulin sensitivity was estimated according to homeostasis model assessment of insulin resistance (HOMA-IR); we defined subjects with values of at least 2.5 as an insulin resistant (n=12) and those with values below 2.5 as insulin sensitive (n=24). We evaluated endothelial function by flow-mediated vasodilation (FMD) of brachial artery during reactive hyperemia, using high-resolution ultrasound. We also measured serum MDA-LDL by a sandwich enzyme-linked immunosorbent assay.

RESULTS

MDA-LDL was significantly higher (146+/-46 vs. 101+/-32 IU/l, P=0.002) and FMD was significantly lower (3.94+/-1.53 vs. 5.59+/-1.62 %, P=0.002) in the insulin-resistant group than in the insulin-sensitive group. The resistant group showed a significant inverse correlation between MDA-LDL and FMD (r=-0.675, P=0.016), while the sensitive group did not (r=0.163, NS). By multivariate regression analysis, MDA-LDL and age were determinants of FMD (R2=0.766) in the insulin-resistant group, while no variable determined FMD in the sensitive group. Nitroglycerin-induced endotheliumindependent dilation was similar in both groups.

CONCLUSIONS

These results suggest that the production of circulating MDA-LDL may be accelerated by insulin resistance, thus impairing endothelial function even in healthy young men.

Insulin secretion and insulin sensitivity at different stages of glucose tolerance: a cross-sectional study of Japanese type 2 diabetes

To evaluate the factors causing glucose intolerance in type 2 diabetes in Japan, insulin secretion and insulin sensitivity were compared across the range of glucose tolerance. Subjects were divided into 3 groups: normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes (DM) according to the criteria of the World Health Organization (WHO). We examined insulin secretion and insulin sensitivity using fasting blood glucose and insulin levels and 75 g oral glucose tolerance test (OGTT). We used homeostasis model assessment (HOMA) beta-cell and insulinogenic index (30 minutes) to estimate insulin secretion and HOMA-insulin resistance (IR) and insulin sensitivity index (ISI) composite for insulin sensitivity. Although insulin resistance plays an important role in the development of diabetes in many ethnic populations, the differences in insulin sensitivity between NGT and IGT and between IGT and DM are small in Japanese patients. On the other hand, as glucose intolerance increases, insulin secretion decreases most remarkably both between NGT and IGT and between IGT and DM in Japanese patients. Decreasing insulin secretion and decreasing insulin sensitivity both occur in developing type 2 diabetes in Japanese patients, but decreased basal and early-phase insulin secretion had more pronounced contribution to glucose tolerance than the indices of insulin sensitivity. Japanese type 2 diabetic patients are characterized by a larger decrease in insulin secretion and show less attribution of insulin resistance.

Diabetes in African Americans: unique pathophysiologic features

Type 2 diabetes is an increasing public health problem among African Americans, especially children. Several features make type 2 diabetes among African Americans unique. First, African-American adults with type 2 diabetes, or Flatbush diabetes, present with diabetic ketoacidosis. Patients are insulin resistant with acute, severe defects in insulin secretion and no islet cell autoantibodies. Following treatment, some insulin secretory capacity is recovered and ketoacidosis generally does not recur. The second is remission in African Americans with type 2 diabetes. Recovery of glucose homeostasis, accompanied by recovery of beta-cell function, follows intensive glycemic regulation. Finally, among African Americans with diabetes who are not obese, normal insulin sensitivity is not uncommon. Such individuals do not have the increased cardiovascular risk of insulin-resistant individuals. Differences in visceral, not subcutaneous, adipose tissue volume appear to determine insulin sensitivity. Understanding the unique physiologic and clinical features of African Americans is critical in designing appropriate treatment strategies.

Body mass index is the most important determining factor for the degree of insulin resistance in non-obese type 2 diabetic patients in Korea

With obesity, increased insulin secretion is needed to compensate for the additional demands and to maintain euglycemia. In contrast to Caucasians, the majority of type 2 diabetic patients belong to the non-obese category in Korea. There appears to be an ethnic difference underlying the pathogenesis in type 2 diabetes mellitus. However, there is only limited data on these subjects. The degree of insulin resistance in 267 Korean non-obese (body mass index [BMI] < 25 kg/m(2)) >/= patients with type 2 diabetes mellitus was analyzed, and the factors responsible for the insulin resistance were examined. The mean age and BMI of the patients were 50.8 +/- 10.6 years and 22.6 +/- 1.8 kg/m(2). Homeostasis model assessment-insulin resistance (HOMA-IR) >/= 2.5 was defined as being insulin resistant according to our data (mean +/- 1.5 SD of 1,917 normal subjects). There was no significant difference according to age, the duration of disease, and the glycosylated hemoglobin (HbA(lc)) levels between the subjects with or without insulin resistance. The HOMA-IR values in the patients with insulin resistance and normal insulin sensitivity were 4.2 +/- 1.4 and 1.5 +/- 0.6, respectively. In the insulin-resistant group, the log-transformed triglyceride (TG) levels were higher and the high-density lipoprotein-cholesterol (HDL-C) levels were lower than those of the insulin-sensitive group (log-transformed TG: 5.2 +/-.6 v 4.9 +/-.7 and HDL-C: 1.13 +/- 0.3 v 1.25 +/- 0.3mmol/L). These differences were still observed after adjusting for BMI. The HOMA-IR value was independently predicted by BMI and HDL-C levels, which explained 7% and 3% in the variability of insulin resistance, respectively. However, the TG levels were not independently associated with the HOMA-IR. Logistic regression analysis showed that the significant factor associated with HOMA-IR was only BMI. These results suggest that the BMI is the most important determinant of insulin resistance, while TG and HDL-C levels might be good markers of insulin resistance in non-obese patients with type 2 diabetes mellitus in Korea.

Platelet count is independently associated with insulin resistance in non-obese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationship between platelet count and insulin resistance in non-obese Japanese type 2 diabetic patients. A total of 163 non-obese Japanese type 2 diabetic patients (112 men and 51 women, aged 36 to 84 years, body mass index [BMI] 16.2 to 26.9 kg/m(2)) were studied. In conjunction with BMI, glycosylated hemoglobin (HbA(1c)), fasting concentrations of plasma glucose and serum lipids (triglycerides, low-density lipoprotein [LDL] cholesterol, high-density lipoprotein [HDL] cholesterol, and total cholesterol), and hematological parameters (platelets, white blood cell count, red blood cell count, hematocrit, hemoglobin) were measured. LDL cholesterol was calculated using the Friedewald formula. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Univariate regression analysis showed that HOMA-IR was positively correlated to BMI (r = 0.465, P <.0001), HbA(1c) (r = 0.423, P <.0001), platelet count (r = 0.310, P <.0001), triglycerides (r = 0.277, P <.0005), white blood cell count (r =.222, P =.005), red blood cell count (r = 0.210, P =.008), hematocrit (r = 0.156, P =.047), total cholesterol (r = 0.178, P =.023), and systolic (r = 0.216, P =.011) and diastolic (r = 0.263, P =.002) blood pressure, and inversely correlated to HDL cholesterol (r = -0.312, P <.0001) level in our diabetic patients. Multiple regression analysis showed that HOMA-IR was independently predicted by BMI (P <.0001, F = 22.45), HbA(1c) (P <.0001, F = 16.15), platelet count (P <.0001, F = 10.75), and serum triglycerides (P <.0001, F = 10.47) levels, which explained 34% of the variability of HOMA-IR in non-obese Japanese type 2 diabetic patients. These results indicate that not only BMI, HbA(1c), and triglycerides levels but also platelet counts are independent predictor of insulin resistance in non-obese Japanese type 2 diabetic patients.

Hypoadiponectinemia is associated with visceral fat accumulation and insulin resistance in Japanese men with type 2 diabetes mellitus

The aim of the present study was to investigate the association of serum adiponectin concentration with regional adiposity and insulin resistance in subjects with type 2 diabetes mellitus. A total of 73 Japanese men with type 2 diabetes (aged 59 +/- 11 years and body mass index [BMI] 23.8 +/- 3.0 kg/m(2), mean +/- SD) were studied. Fasting serum adiponectin and leptin concentrations were determined by radioimmunoassay. Regional adiposity was measured by abdominal computed tomography (CT) at the umbilical level, and insulin resistance was estimated by homeostasis model assessment (HOMA-R). Univariate regression analysis showed that serum adiponectin levels were negatively correlated with subcutaneous and visceral fat areas. With multivariate regression analysis, visceral fat area was a predominant determinant of serum adiponectin levels. In contrast, subcutaneous fat area was strongly associated with serum leptin concentrations. Among subcutaneous and visceral fat areas, BMI, and serum leptin levels, both subcutaneous and visceral fat areas were independently associated with HOMA-R. In another model incorporating serum adiponectin levels, serum adiponectin levels were selected as an independent determinant of HOMA-R instead of visceral fat area. In conclusion, hypoadiponectinemia was associated with visceral fat accumulation rather than subcutaneous fat depot in Japanese men with type 2 diabetes mellitus. Both subcutaneous and visceral fat accumulation contribute to insulin resistance in these subjects, and the contribution of visceral fat may be mediated, in part, by hypoadiponectinemia.

Relationship of regional adiposity to serum leptin level in nonobese Japanese type 2 diabetic male patients

BACKGROUND

The aim of the present study was to investigate the relationships between serum leptin levels and regional adipose fat area, BMI, and the measures of variables including serum insulin in nonobese Japanese type 2 diabetic patients.

METHODS

A total of 121 nonobese Japanese type 2 diabetic patients [aged 35 to 83 years, body mass index (BMI) (15.4 to 26.8 kg/m(2))] were studied. They all were male patients. In conjunction with serum leptin level, BMI, glycosylated hemoglobin (HbA(1c)), and fasting concentrations of plasma glucose and serum insulin and lipids (triglycerides, total and HDL cholesterol) were measured.

RESULTS

Univariate regression analysis showed that serum leptin levels were positively correlated to subcutaneous (r=0.566, P<0.0001) and visceral (r=0.481, P<0.001) fat area in our diabetic patients. Furthermore, serum leptin levels were positively correlated to serum insulin (r=0.517, P<0.0001), BMI (r=0.428, P<0.0001), serum triglycerides (r=0.279, P<0.005), and age (r=0.225, P<0.05). There was, however, no relationship between serum leptin levels and measures of other variables including total and HDL cholesterol. Multiple regression analyses showed that serum leptin levels were predicted by subcutaneous fat area (F=5.92, P<0.0001) and serum insulin level (F=5.60, P<0.0001), which explained 29.0% of the variability of serum leptin concentrations in our nonobese Japanese type 2 diabetic male patients. Visceral fat area, BMI, serum triglycerides, and age, however, were not independently associated with serum leptin levels in our patients.

CONCLUSIONS

These results indicate that serum leptin levels are reflective of subcutaneous fat area in nonobese Japanese type 2 diabetic male patients.

Postprandial lipemia in hypertension

OBJECTIVE

Many studies have shown that patients with coronary artery disease have an exaggerated rise and a delayed fall of plasma triglyceride (TG) concentration postprandially. We examined whether patients with essential hypertension have the same response to a fatty meal.

METHODS

A fatty meal (350g per 2 m(2) body surface with 83.5% fat) was given to 25 patients with essential hypertension (H) and to 25 normotensives (N). The two groups were matched for age, body mass index, lipid profile, basal glucose and insulin concentrations, and an index of homeostasis model of insulin resistance (HOMA-IR). A quantitative insulin sensitivity check index (QUICKI) was calculated. Blood samples were taken at 0, 4, 6, and 8 hours after the fatty meal. Lipid variables were measured in all samples. Blood glucose and insulin levels were measured in the fasting state.

RESULTS

Total and high density lipoprotein cholesterol, apolipoprotein A1 and B, lipoprotein (a), HOMA-IR and QUICKI did not differ significantly over time between the groups. The plasma TG concentration (mg/dL) increased significantly after fat loading in H (from 118 +/- 31 to 284 +/- 137 at 4 hours, 327 +/- 93 at 6 hours and 285 +/- 71 at 8 hours) compared to N group (from 105 +/- 29 to 150 +/- 38 at 4 hours, 148 +/- 40 at 6 hours and 115 +/- 34 at 8 hours), p = 0.001, p < 0.001 and p < 0.001, respectively.

CONCLUSION

This study suggests that patients with hypertension have an exaggerated response and delayed clearance of plasma TG concentration after fat loading.

Porphyromonas gingivalis infection is associated with carotid atherosclerosis in non-obese Japanese type 2 diabetic patients

The aim of the present study was to investigate whether non-obese Japanese type 2 diabetic patients with porphyromonas gingivalis infection have atherosclerotic vascular diseases. A total of 134 non-obese Japanese type 2 diabetic patients (96 men and 38 women, aged 36 to 84 years, body mass index [BMI] 20.1 to 26.9 kg/m(2)) were studied. In conjunction with BMI, glycosylated hemoglobin (HbA(1c)), fasting glucose, and serum lipids (triglycerides, total cholesterol, high-density lipoprotein [HDL] cholesterol, low-density lipoprotein [LDL] cholesterol) were measured. LDL cholesterol was calculated using the Friedewald formula. Using high-resolution B-mode ultrasound scan, we measured intimal medial thickness (IMT) in plaque-free segments of bilateral common carotid arteries, and the mean of IMT in 2 vessels was used for the analysis. Furthermore, we calculated the degree of stenosis in plaque segments of bilateral common carotid arteries. The degree of carotid atherosclerosis was expressed as a percentage ratio between the area of plaque and that of the lumen using the formula (Lumen Area Residual - Lumen Area)/Lumem Area x 100. Both the areas were automatically measured by the system on a frozen transverse scanning plane at the site of maximal narrowing. When 2 or more plaques were present in the vessel, only that causing the greatest degree of stenosis was considered for analysis. Values represent mean+/-SEM unless otherwise stated. Immunoglobulin G (IgG) titer against porphyromonas gingivalis was 245 +/- 65 (mean +/- 2 SD) in nondiabetic healthy subjects. In contrast, there was a wide variation in IgG titer against porphyromonas gingivalis in type 2 diabetic patients studied (range, 16 to 26,800). Thus, we classified our type 2 diabetic patients into 2 subpopulations according to the value of mean +/- 2 SD (= 310) of nondiabetic healthy subjects: one with high IgG titer against porphyromonas gingivalis (>310) (1,422 +/- 408) and the other with normal IgG titer against porphyromonas gingivalis (<310) (152 +/- 10, P =.002). The populations did not differ with respect to age, sex, BMI, fasting glucose, HbA(1c), serum triglycerides, total, HDL, and LDL cholesterol levels. Although the mean IMT in plaque-free segments was not different between the 2 groups (0.73 +/-0.03 v 0.68 +/- 0.02 mm, P =.098), the degree of stenosis in plaque segments was significantly higher in the high IgG titer group (12.0% +/- 2.2%) than in normal one (5.5% +/- 1.4%, P =.009). From these results, it can be concluded that porphyromonas gingivalis infection, although still a subclinical infection, is associated with atherosclerotic vascular disease in non-obese Japanese type 2 diabetic patients.

Impaired beta-cell function and insulin sensitivity in Japanese subjects with normal glucose tolerance

The development of type 2 diabetes mellitus is characterized by both impaired beta-cell function and increasing insulin resistance. To clarify the roles of them in developing type 2 diabetes, we evaluated insulin resistance by HOMA-IR and insulin secretion by HOMA beta-cell in 453 Japanese subjects whose fasting plasma glucose (FPG) and HbA(1c) levels were within normal range. HOMA beta-cell was found to decrease in the over 30 years groups, while HOMA-IR increased with body mass index (BMI). To analyze the reserve capacity of insulin secretion and insulin sensitivity, the 67 of them, who underwent a standard oral glucose tolerance test and were diagnosed with normal glucose tolerance (NGT), were divided into four degrees of BMI age-adjusted to 50 years. They were compared for insulinogenic index and ISI composite proposed by Matsuda and DeFronzo across the range of BMI. ISI composite was significantly less in the highest BMI group, while insulin secretion did not increase in the higher BMI groups. The subjects with higher BMI had remarkably lower insulinogenic indices than those with lower BMI. These data suggest that insulin secretory reserve is insufficient to compensate for increased insulin resistance in Japanese people with NGT at about 50 years of age.

Plasma leptin concentrations are independently associated with insulin sensitivity in lean and overweight cats

This study investigated relationships between plasma leptin, insulin concentrations, insulin sensitivity and glucose tolerance in lean and overweight cats. Leptin concentrations were measured in 16 cats during glucose tolerance tests before and after gaining weight, and after feeding a test meal in overweight cats. An important finding of this study is that in both lean (r=-0.79) and overweight (r=-0.89) cats, the higher the leptin concentrations, the more insulin resistant the cat, independent of the degree of adiposity. Leptin concentrations at baseline and after consuming a meal tended to be higher in overweight cats with glucose intolerance, compared to overweight cats with normal glucose tolerance, although the difference was not significant. After feeding the test meal to overweight cats in the early morning, plasma leptin concentrations initially decreased before subsequently rising to peak 15 h later, which coincided with late evening. The leptin peak occurred 9 h after the insulin peak following ingestion of the test meal. Importantly, this study suggests that increased leptin concentrations may contribute to the diminished insulin sensitivity seen in overweight cats. Alternatively, the compensatory hyperinsulinaemia found with insulin resistance in overweight cats could stimulate leptin production.