Insulin Resistance and Hypertension: Seven-Year Follow-Up Study in Middle-Aged Japanese Men (the KEIO Study)

Relationships among the β3-adrenargic receptor gene Trp64Arg polymorphism, hypertension, and insulin resistance in a Japanese population

A polymorphism in the ADRB3 gene (Trp64Arg) has been associated with obesity, insulin resistance, and hypertension. This cross-sectional study investigated the relationships among this polymorphism, hypertension, and insulin resistance values (HOMA-IR) in 719 Japanese subjects aged 40 years and older. The genotype frequencies of Trp64Trp (homozygous, wild), Trp64Arg (heterozygous, variant), and Arg64Arg (homozygous, variant) were 466 (65%), 233 (32%), and 20 (3%), respectively. Insulin resistance was associated with an increased risk of hypertension in a Japanese population. This relationship was dependent on the presence or absence of the Trp64Arg polymorphism (odds ratio, 2.054; confidence interval, 1.191 to 3.541; P value, 0.010). Therefore, the Trp64Arg polymorphism of ADRB3 was associated with hypertension and insulin resistance in a healthy Japanese population. This relationship, which was dependent on the polymorphism, may predict the development of hypertension and diabetes.

Assessment of preferred methods to measure insulin resistance in Asian patients with hypertension

Insulin resistance (IR), a metabolic risk factor, is linked to the pathogenetic mechanism of primary hypertension. Detecting IR in the patients with hypertension will help to predict and stratify the added cardiovascular risk, institute appropriate IR management, and manage hypertension optimally. There are many methods for assessing IR, each with distinct advantages and disadvantages. The euglycemic insulin clamp and intravenous glucose tolerance test, gold standards for measuring IR, are used in research but not in clinical practice. Homeostatic model assessment (HOMA-IR), a method for assessing β-cell function and IR, is frequently applied presently, particularly in Asia. Besides, the triglyceride-glucose index (TyG) first published by South American authors showed a good correlation with the insulin clamp technique and HOMA-IR index. This simple, convenient, and low-cost TyG index is of research interest in many countries in Asia and can be used to screen for IR in the Asian hypertensive community.

Predicting factors related with uncured hypertension after retroperitoneal laparoscopic adrenalectomy for unilateral primary aldosteronism

Although unilateral primary aldosteronism (PA) is the most common surgically correctable cause of hypertension, the cure rate varies widely. The predicting factors related to uncured hypertension are not completely established. This study was designed to determine predicting factors associated with resolution of hypertension after adrenalectomy for PA.The records of unilateral PA patients who had undergone retroperitoneal laparoscopic adrenalectomy were retrospectively reviewed from January 2010 to December 2017 in a single center. Patient demographics and preoperative factors were analyzed, including age, sex, smoking history, family history of hypertension, the presence of diabetes, body mass index (BMI), systolic blood pressure, diastolic blood pressure, biochemical results and tumor characteristics. Univariate and multivariate Logistic regression analysis were used for statistical assessment.126 patients with unilateral PA were enrolled, and the mean age at the time of surgery was 54.2 years. Of these patients, 74 (58.7%) were women, and the mean BMI and duration of hypertension were 26 kg/m and 61 months, respectively. Hypertension was cured in 46% patients, of the patients with uncured hypertension, 91% had improved control of hypertension. In univariate analysis, age (P = .03), BMI (P = .01), duration of hypertension >5 years (P = .03), preoperative antihypertensive agents>2 (P = .02), contralateral abnormalities (P = .03) were the main factors related to uncured hypertension after adrenalectomy. In multivariate regression analysis, uncured hypertension was independently associated with obesity (25.00-29.99: odds ratio [OR], 2.97, P < .02; ≥30: OR, 6.42, P < .01), duration of hypertension >5 years (OR, 6.25, P < .01), preoperative antihypertensive agents >2 (OR, 5.30, P < .001), and contralateral adrenal abnormalities (OR, 8.38, P < .01).The hypertension cure rate of unilateral adrenalectomy in PA is not high. Obesity, duration of hypertension >5 years, preoperative antihypertensive agents >2 and contralateral adrenal abnormalities were independently associated with uncured hypertension.

Slightly increased BMI at young age is a risk factor for future hypertension in Japanese men

Background

Hypertension is developed easily in Asian adults with normal body mass index (BMI) (~23 kg/m²), compared with other ethnicities with similar BMI. This study tested the hypothesis that slightly increased BMI at young age is a risk factor for future hypertension in Japanese men by historical cohort study.

Methods

The study participants were 636 male alumni of the physical education school. They had available data on their physical examination at college age and follow-up investigation between 2007 and 2011. The participants were categorized into six categories: BMI at college age of <20.0 kg/m², 20.0–21.0kg/m², 21.0–22.0kg/m², 22.0–23.0kg/m², 23.0–24.0kg/m², and ≥24.0kg/m², and the incidence of hypertension was compared.

Results

This study covered 27-year follow-up period (interquartile range: IQR: 23–31) which included 17,059 person-years of observation. Subjects were 22 (22–22) years old at graduated college, and 49 (45–53) years old at first follow-up investigation. During the period, 120 men developed hypertension. The prevalence rates of hypertension for lowest to highest BMI categories were 9.4%, 14.6%, 16.1%, 17.5%, 30.3%, and 29.3%, respectively (p<0.001 for trend), and their hazard ratios were 1.00 (reference), 1.80 (95%CI: 0.65–4.94), 2.17 (0.83–5.64), 2.29 (0.89–5.92), 3.60 (1.37–9.47) and 4.72 (1.78–12.48), respectively (p<0.001 for trend). This trend was similar after adjustment for age, year of graduation, smoking, current exercise status and current dietary intake.

Conclusion

Slightly increased BMI at young age is a risk factor for future hypertension in Japanese men.

The Determinants of Leptin Levels in Diabetic and Nondiabetic Saudi Males

Objective. This study aimed to identify the main determinants of serum leptin levels. Methods. A sample of 113 Saudi adult males (55 diabetic and 58 nondiabetic) was selected according to the inclusion and exclusion criteria identified below. Blood samples were taken from participants after fasting for 12 hours. For diabetic patients, the insulin dose was given 12 hours before. In general, the study instrument consisted of blood biochemical tests. Metabolic parameters, glycosylated hemoglobin (HbA1c), low-density lipoprotein (LDL), high-density lipoprotein (HDL), cholesterol, and triglyceride (TG), and adipokines, leptin, adiponectin, visfatin, and resistin, were measured. Multivariate model was utilized to identify the relationship between leptin levels and the independent variables. Results. When adjusted for resistin in the diabetic group, the results demonstrated a significant relationship between visfatin, LDL and TG, and leptin levels (p < 0.05). However, when controlled for resistin, the effect of LDL and TG disappeared while that of visfatin stayed in the model. For the nondiabetic group, the results indicated a significant relationship between insulin, BMI, and leptin levels when adjusted for resistin (p < 0.05). However, the effect of insulin disappeared when the model was controlled for resistin. The study results found no relationship between leptin and adiponectin levels in either the diabetic or nondiabetic group and whether adjusted or controlled for resistin. Conclusion. This study provided better understanding of the metabolism of leptin and unveiled the major determinants of leptin levels in diabetic and nondiabetic males. In conclusion, these results show that the association between leptin and metabolic parameters decreases with the progress of disease.

Optimal Cut-Offs of Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) to Identify Dysglycemia and Type 2 Diabetes Mellitus: A 15-Year Prospective Study in Chinese

Background

The optimal reference range of homeostasis model assessment of insulin resistance (HOMA-IR) in normal Chinese population has not been clearly defined. Here we address this issue using the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS), a prospective population-based cohort study with long-term follow-up.

Material & Methods

In this study, normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) were defined according to the 1998 World Health Organization criteria. Dysglycemia referred to IFG, IGT or T2DM. This study comprised two parts. Part one was a cross-sectional study involving 2,649 Hong Kong Chinese subjects, aged 25–74 years, at baseline CRISPS-1 (1995–1996). The optimal HOMA-IR cut-offs for dysglycemia and T2DM were determined by the receiver-operating characteristic (ROC) curve. Part two was a prospective study involving 872 subjects who had persistent NGT at CRISPS-4 (2010–2012) after 15 years of follow-up.

Results

At baseline, the optimal HOMA-IR cut-offs to identify dysglyceia and T2DM were 1.37 (AUC = 0.735; 95% confidence interval [CI] = 0.713–0.758; Sensitivity [Se] = 65.6%, Specificity [Sp] = 71.3%] and 1.97 (AUC = 0.807; 95% CI = 0.777–0.886; Se = 65.5%, Sp = 82.9%) respectively. These cut-offs, derived from the cross-sectional study at baseline, corresponded closely to the 75^th (1.44) and 90^th (2.03) percentiles, respectively, of the HOMA-IR reference range derived from the prospective study of subjects with persistent NGT.

Conclusions

HOMA-IR cut-offs, of 1.4 and 2.0, which discriminated dysglycemia and T2DM respectively from NGT in Southern Chinese, can be usefully employed as references in clinical research involving the assessment of insulin resistance.

Associations of Different Adipose Tissue Depots with Insulin Resistance: A Systematic Review and Meta-analysis of Observational Studies

Fat distribution is strongly associated with insulin resistance, a risk factor for type 2 diabetes and cardiovascular diseases. However, associations of different adipose tissue depots or/and obesity indices with insulin resistance have not been systematically evaluated. In this study we examined associations of different adipose tissue depots/obesity indices with insulin resistance, as measured by homeostatic model assessment of insulin resistance (HOMA-IR) in observational studies. A total of 40 studies with 56 populations and 29 adipose tissue depots/obesity indices were included in the meta-analysis. There were strong correlation between HOMA-IR and visceral fat mass (r = 0.570, 95% confidence interval(CI): 0.424~0.687), total fat mass (r = 0.492, 95%CI: 0.407~0.570), body mass index (r = 0.482, 95%CI: 0.445~0.518) and waist circumference (r = 0.466, 95%CI: 0.432~0.500), except lower extremity fat (r = 0.088, 95%CI: -0.116~0.285). Sample size, diabetic status, gender, mean of body mass index, and race contributed to heterogeneity of these associations. This study showed a positive correlation between insulin resistance and most adipose tissue depots/obesity indices, and the strongest association is for visceral fat mass.

Euglycemic Clamp Insulin Sensitivity and Longitudinal Systolic Blood Pressure

Insulin resistance may be an independent risk factor for the development of hypertension, but change in blood pressure (BP) over time has not been adequately studied in healthy individuals fully characterized for insulin sensitivity. In the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) study, we measured insulin sensitivity (M/I) using the euglycemic clamp technique in 1073 healthy European adults (587 women, 486 men) aged 30 to 60 years followed up 3 years later. Systolic BP (SBP) at baseline was higher in insulin-resistant women (ie, those in the low sex-specific M/I tertile) compared with those in the intermediate ( P <0.001) or high tertiles ( P =0.06; mean±SD: 117±13, 111±12, 114±12 mm Hg, respectively). It did not differ across M/I tertiles in men. After adjustment for age, body mass index, baseline SBP, and other covariates, low insulin sensitivity (M/I) predicted a longitudinal rise in SBP in women but not in men; M/I was not associated with change in diastolic BP. SBP rose over time in both sexes and within all M/I tertiles ( P <0.05), except in women with high insulin sensitivity. Therefore, in women (but not in men), low insulin sensitivity was associated with higher SBP at 3 years, and high insulin sensitivity was associated with a lower rise in SBP over time.

Prediction of metabolic syndrome using artificial neural network system based on clinical data including insulin resistance index and serum adiponectin

OBJECTIVE

This study aimed to predict the 6-year incidence of metabolic syndrome (MetS) using an artificial neural network (ANN) system and multiple logistic regression (MLR) analysis based on clinical factors, including the insulin resistance index calculated by homeostasis model assessment (HOMA-IR).

DESIGN

Subjects were recruited from participants in annual health check-ups in both 2000 and 2006. A total of 410 Japanese male teachers and other workers at Keio University, 30-59 years of age at baseline, participated in this retrospective cohort study.

MEASUREMENTS

Clinical parameters were randomly divided into a training dataset and a validation dataset, and the ANN system and MLR analysis were applied to predict individual incidences. The leave some out cross validation method was used for validation.

RESULTS

The sensitivity of the prediction was 0.27 for the MLR model and 0.93 for the ANN system, while specificities were 0.95 and 0.91, respectively. Sensitivity analysis employing the ANN system identified BMI, age, diastolic blood pressure, HDL-cholesterol, LDL-cholesterol and HOMA-IR as important predictors, suggesting these factors to be non-linearly related to the outcome.

CONCLUSION

We successfully predicted the 6-year incidence of MetS using an ANN system based on clinical data, including HOMA-IR and serum adiponectin, in Japanese male subjects.

Matsuda-DeFronzo insulin sensitivity index is a better predictor than HOMA-IR of hypertension in Japanese: the Tanno-Sobetsu study

Here we examined whether the Matsuda-DeFronzo insulin sensitivity index (ISI-M) is more efficient than the homeostasis model assessment of insulin resistance (HOMA-IR) for assessing risk of hypertension. Cross-sectional and longitudinal analyses were conducted using normotensive subjects who were selected among 1399 subjects in the Tanno-Sobetsu cohort. In the cross-sectional analysis (n=740), blood pressure (BP) level was correlated with HOMA-IR and with ISI-M, but correlation coefficients indicate a tighter correlation with ISI-M. Multiple linear regression analysis adjusted by age, sex, body mass index (BMI) and serum triglyceride level (TG) showed contribution of ISI-M and fasting plasma glucose, but not of HOMA-IR. In the longitudinal analysis (n=607), 241 subjects (39.7%) developed hypertension during a 10-year follow-up period, and multiple logistic regression indicated that age, TG, systolic BP and ISI-M, but not HOMA-IR, were associated with development of hypertension. In subjects <60 years old, odds ratio of new-onset hypertension was higher in the low ISI-M group (ISI-M, less than the median) than in the high ISI-M group for any tertile of BMI. In conclusion, ISI-M is a better predictor of hypertension than is HOMA-IR. Non-hepatic IR may be a determinant, which is independent of TG, BP level and BMI, of the development of hypertension.

Insulin resistance and risk of incident hypertension among men

J Clin Hypertens (Greenwich). 2009;11:483-490. (c) 2009 Wiley Periodicals, Inc.The independent association between insulin resistance and the development of hypertension remains in doubt because insulin resistance correlates with other metabolic factors also proposed to be associated with hypertension. The authors examined the association between the insulin sensitivity index and incident hypertension in a prospective nested case-control study among 1453 men (mean age, 61 years) who participated in the Health Professionals' Follow-up Study. The authors computed the insulin sensitivity index for each man in the study based on fasting insulin and triglyceride levels. Logistic regression was performed conditioned on age and adjusted for standard hypertension risk factors as well as renal function, cholesterol, and uric acid. The insulin sensitivity index was 6% lower in the cases compared with the controls (P<.001). The multivariable odds ratio for hypertension comparing the lowest with highest quartile of insulin sensitivity index was 1.09 (0.71-1.65) among the entire sample. However, the association between the insulin sensitivity index and incident hypertension differed significantly by age (P interaction <.001). Among men younger than 60 years, the multivariable odds ratio for the lowest compared with highest quartile was 1.93 (1.01-3.71) but was 0.67 (0.37-1.24) among older men. Insulin resistance is independently associated with incident hypertension among younger men.

Relationship of dysregulation of glucose metabolism with white-coat hypertension: the Ohasama study

Characteristics of glucose metabolism in subjects with white-coat hypertension (WCHT) have not been fully investigated. The purpose of this study was to determine the relationship between glucose metabolism and WCHT on the basis of blood pressure (BP) at home (HBP) in the general population. Participants were from Ohasama, a rural Japanese community, and included 466 residents (mean age, 61.0 years) who had no history of diabetes mellitus. HBP and oral glucose tolerance test values were measured. Participants were classified into four groups on the basis of their HBP and casual-screening BP (CBP) values: normotension (NT) (HBP<135/85 mm Hg, CBP<140/90 mm Hg); WCHT (HBP<135/85 mm Hg, CBP>/=140/90 mm Hg); masked hypertension (HBP>/=135/85 mm Hg, CBP<140/90 mm Hg); or sustained hypertension (SHT) (HBP>/=135/85 mm Hg, CBP>/=140/90 mm Hg). The relationships between glucose metabolism and BP among the four groups were examined using multivariate analysis adjusted for possible confounding factors. Factors in relation to glucose metabolism, such as fasting glucose level, 2-h postchallenge glucose level and homeostasis model assessment-insulin resistance index, were significantly higher in subjects with WCHT and SHT than in those with NT (all P<0.03). When men and women were analyzed separately, these relationships were more pronounced in women. Our results suggest that dysregulation of glucose metabolism in WCHT might contribute to the increase in the long-term cardiovascular risk among the general population.

Relations between serum reactive oxygen metabolites (ROMs) and various inflammatory and metabolic parameters in a Japanese population

AIM

Both oxidative stress and inflammation are known to play roles in the pathogenesis of cardiovascular disease. We investigated the relations between reactive oxygen metabolites (ROMs) and various inflammatory and metabolic parameters in a Japanese population.

METHODS

We analyzed 48 male and 69 female subjects, aged 25 to 65 years, who underwent an annual health checkup in our university. Serum ROM level was assayed using a free radical elective evaluator. We also measured serum concentrations of high-sensitivity C-reactive protein (hsCRP), insulin, and high molecular weight (HMW) adiponectin.

RESULTS

Although the serum ROM level in females (347+/-83 Carr U) was slightly higher than in males (333+/-53 Carr U), this was not statistically significant. In the 48 male subjects, the ROM level negatively correlated with age (r=-0.344, p=0.0161), and positively correlated with the hsCRP level (r=0.306, p=0.0338). In the 69 female subjects, the ROM level negatively correlated with serum creatinine (r=-0.293, p=0.0141), and positively correlated with insulin (r=0.278, p=0.0202), the insulin resistance index (r=0.286, p=0.0170) and hsCRP levels (r=0.487, p<0.0001). Stepwise multiple regression analysis revealed that serum hsCRP, creatinine, and age were independently correlated with the serum ROMs level (R2=0.365; F value highest for hsCRP). When the study subjects were divided into tertiles according to the ROM level, serum hsCRP was significantly different among the three groups: its level was highest in the highest tertile of ROMs (p<0.001).

CONCLUSION

These results suggest that the serum ROM level is closely associated with serum hsCRP in Japanese adult subjects.

Inverse associations between muscle mass, strength, and the metabolic syndrome

The metabolic syndrome (MetS) is a clustering of individual cardiovascular disease risk factors, which doubles the risk of early mortality. The authors' aimed to determine the prevalence and population attributable risk (PAR%) of the MetS among men according to demographic, physical, and lifestyle risk factors. A cross-sectional study was conducted in 1195 men in the Florey Adelaide Male Ageing Study, a regionally representative cohort of Australian men aged 35 to 81 years conducted in 2002-2005 (response rate, 45.1%). Prevalent MetS was determined according to the Adult Treatment Panel III (ATPIII) and International Diabetes Federation (IDF) classifications; and an extensive list of demographic, physical (including muscle strength, body composition by dual-energy x-ray absorptiometry, sex hormones), and lifestyle factors was accounted for. Prevalence estimates were 37.7% and 41.8% for ATPIII and IDF classifications. Odds ratios for present MetS were determined using multiple-adjusted logistic regression. Odds for present ATPIII MetS decreased (in order of importance) for lower insulin and increased for lower muscle mass, lower strength, and 3+ medical conditions. Odds for present IDF MetS decreased for lower insulin and increased for lower muscle mass, strength, and sex hormone-binding globulin levels; older age; and being married. Significant PAR% due to lowest insulin, muscle mass, and strength quarters were -44%, 27%, and 17% for the ATPIII Met, and -48%, 31%, and 20% for the IDF MetS. A substantial proportion of MetS cases would have been theoretically prevented if prior exposure to low muscle mass and strength were eradicated (PAR% ranged from 14% to 24%). Findings indicate that insulin resistance is a central abnormality in the MetS and that muscle mass and strength are strong protective factors independent of insulin resistance and abdominal fat accumulation. If confirmed prospectively, increases in muscle mass and strength needed to prevent a substantial proportion of MetS cases would be achievable with a short-term strength training intervention.

High-molecular-weight adiponectin is a predictor of progression to metabolic syndrome: a population-based 6-year follow-up study in Japanese men

Adiponectin is an adipocyte-specific secretory protein, which possesses antidiabetic and antiatherosclerotic properties. Adiponectin exists as multimers in serum, and high-molecular-weight (HMW) adiponectin is particularly considered to be the active form of the protein. The objective of the present study was to examine whether decreased HMW adiponectin is a predictor of progression to metabolic syndrome during a 6-year follow-up period in Japanese men. The study subjects were 416 Japanese men without metabolic syndrome, aged 30 to 59 years at baseline, who had participated in annual health checkups in both 2000 and 2006. Low concentration of HMW adiponectin (< or =2.65 microg/mL) was associated with substantially higher hazard ratio of the progression to metabolic syndrome after adjustment for age and body mass index (hazard ratio, 1.561; 95% confidence interval, 1.051-2.292; P = .028). The number of subjects with the progression to metabolic syndrome in each tertile based on baseline HMW adiponectin concentration was significantly different among the 3 groups (HMW adiponectin: chi(2) = 7.473, P = .0238; total adiponectin: chi(2) = 4.477, P = .1066; HMW-total adiponectin ratio: chi(2) = 1.676, P = .4325). It was suggested that decreased HMW adiponectin is a predictor of the progression to metabolic syndrome in a 6-year follow-up study of Japanese men. Furthermore, it was suggested longitudinally that measuring HMW adiponectin is efficient to predict the progression to metabolic syndrome compared with measuring total adiponectin or HMW-total adiponectin ratio.

HOMA-estimated insulin resistance is associated with hypertension in Iranian diabetic and non-diabetic subjects

The relationship between insulin resistance (IR) and essential hypertension (HTN) is controversial. The aim of this study was to determine the association of IR estimated by homeostasis model assessment of insulin resistance (HOMA-IR) and HTN in a large sample of Iranian diabetic and non-diabetic population. A total of 2047 diabetic and non-diabetic individuals with or without HTN, aged 30-75 yrs, who were referred to a university general hospital between November 2004 and April 2007 were included in this study. Demographic data and anthropometric characteristics of participants were recorded. Fasting blood samples were collected, and fasting plasma glucose (FPG), serum creatinine, lipids, insulin, C-peptide and HbA1c were measured. HOMA-IR and HOMA derived Beta-cell function (HOMA-B) were also calculated. Age, sex and waist girth adjusted HOMA-IR values were compared between hypertensive and normotensive subjects. Hypertensive patients had significantly higher HOMA-IR than age-, sex-, and waist girth-adjusted normotensive individuals in both non-diabetic (2.163 +/- 0.08 and 1.75 +/- 0.03, p < 0.001) and diabetic (3.40 +/- 0.10 and 3.07 +/- 0.09, p < 0.05) groups. Multivariate logistic regression analysis showed that after adjustment for age, sex, waist girth, BMI, triglyceride, total cholesterol, FPG, and C-peptide, HOMA-IR was a significant independent predictor of HTN in all subjects (odds ratio = 1.117, CI 95% = 1.026-1.216, p < 0.05) and in diabetic and non-diabetic subjects separately (odds ratio = 1.102, CI 95% = 1.009-1.203, p < 0.05 and odds ratio = 1.328, CI 95% = 1.116-1.580, p < 0.01, respectively). In conclusion, this study showed that IR is associated with HTN in Iranian diabetic and non-diabetic subjects.

Endothelial nitric oxide synthase Glu298Asp gene polymorphism is associated with hypertensive response to exercise in well-controlled hypertensive patients

PURPOSE

Hypertensive response to exercise (HRE) is known to be an adverse prognostic factor for future cardiovascular events and may be associated to endothelial dysfunction. Previous studies regarding endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism focused upon its relation to hypertension. In this study, we hypothesize that the polymorphism may be associated with inherent difference in endothelial response to exercise.

PATIENTS AND METHODS

Two hundred sixty nine patients who underwent treadmill test were enrolled in this study; 77 patients (mean age 55.8 +/- 9.4 years) had hypertensive response (peak systolic BP of > or = 210 mmHg in men and > or = 190 mmHg in women). Pulse wave velocity (PWV) was measured on 153 patients of them. The Glu298Asp exchange in exon 7 was determined by the methods of single base extension with amplifying primers and probes for TaqMan.

RESULTS

The percentages of the GG, GT and TT genotypes were 81.0, 18.6 and 0.4 %, respectively. The presence of GT or TT genotype was independently associated with prevention of HRE when controlled for age, sex, baseline systolic BP and homeostatic model assessment (HOMA) index (OR=0.35, p=0.016). Subgroup analysis showed that preventive effect for HRE of T allele was significant in females (p < 0.001) and patients without insulin resistance (p=0.009).

CONCLUSION

In our study, eNOS Glu298Asp polymorphism was significantly associated with HRE. This result suggests that the presence of T allele of the Glu298Asp polymorphism may be a favorable factor to in preventing HRE, especially in female and patients without insulin resistance.

Fluid mechanical and physicochemical modeling interprets hypertension to be capable of inducing secondary complications

The relationship of hypertensives and many pathological syndromes still remains unclear. A mathematical model in terms of the fluid mechanics and physicochemical analyses is established to correlate the plasma viscosity, the shear stress and the rate of shear in blood stream with the ligand-receptor dissociation constant. This model has arrived at the conclusive results that high viscosity, high rate of shear created in the blood streams, and the peripheral resistance may act as important preceding factors to induce a serial subsequent pathological clinical manifestations. High viscosity may interfere with the ligand-receptor combination, in contrast, high rate of shear may knock the ligand (s) off the existing ligand-receptor complex, while elevation of peripheral resistance may slow down the blood flow rate, resulting in a diminished dissociation of ligand-receptor complex. This model has successfully interpreted the possible cause of some post-hypertensive abnormal outcome manifestations involving obstructive and degenerative stenosis (such as renal artery stenosis), growth retardation, blood vessel detriment, coarctation of aorta, coronary thrombotics, atherosclerosis, hyperinsulinemia, diabetes, obesity, hypothyroidism, infertility, and at the worst, carcinoma, etc.

Normal and high-normal blood pressures, but not body mass index, are risk factors for the subsequent occurrence of both preeclampsia and gestational hypertension: a retrospective cohort study

Blood pressure (BP) levels and body mass index (BMI) are known as risk factors for preeclampsia and gestational hypertension. However, there have been few investigations regarding the effects of BP and BMI levels on preeclampsia and gestational hypertension in the same cohort. In the present study, we conducted a retrospective cohort study using multiple logistic regression analysis. The cohort included 1,518 patients without nephritis. The unadjusted odds ratios (ORs) of preeclampsia and gestational hypertension were increased in pregnant women with normal BP (120-129 mmHg systolic or 80-84 mmHg diastolic), high-normal BP and hypertension in the second trimester compared to those with optimal BP. The unadjusted ORs of preeclampsia and gestational hypertension were also increased in obese women in the pre-pregnancy period compared to women with normal range BMI. When adjustment was made for both the BP levels and pre-pregnancy BMI levels, the ORs (95% confidence intervals) of normal BP, high-normal BP, hypertension and obesity for the subsequent occurrence of preeclampsia were 5.1 (2.2-12), 8.3 (3.1-22), 16 (5.0-50) and 2.0 (0.67-5.9), and those for the subsequent occurrence of gestational hypertension were 7.0 (2.6-19), 7.4 (2.1-25), 22 (6.1-83) and 1.3 (0.33-4.8), respectively. For the subsequent occurrence of preeclampsia or gestational hypertension, normal BP, high-normal BP and hypertension in the second trimester may be independent risk factors. Obesity in the pre-pregnancy period, however, may not be an independent risk factor.

Differential impact of family history on age-associated increase in the prevalence of hypertension and diabetes in male Japanese workers

Family history and aging are independent risk factors for the development of hypertension as well as for the development of diabetes. However, it is unclear how the family histories influence the rate of age-associated increase in these diseases. Moreover, despite the fact that hypertension and diabetes often occur concomitantly, it is not known whether family history of hypertension increases the risk of diabetes or vice versa. To gain an insight into these questions, we investigated the cross-sectional prevalence and family history of hypertension and diabetes in 1,123 male subjects (mean age, 42.1 +/- 12 years; range, 20-60 years) who participated in annual medical check-ups. The data were analyzed by 10-year age groups (20s, 30s, 40s and 50s). The prevalence of hypertension increased with age group either in the absence (12% in the 20s and 39% in the 50s) or in the presence (21% in the 20s and 59% in the 50s) of family history of hypertension, and thus the increasing rate of prevalence with age was not affected by family history. The prevalence of diabetes in the absence of family history of diabetes was low until the 40s (< 1.2%) but it jumped in the 50s (4.3%). On the other hand, in the presence of family history, the prevalence was 4% in the 20s and progressively increased to 20% in the 50s. The impact of family history on the risk of diabetes was strong and appeared to increase with age. Family history of hypertension did not increase the risk of diabetes, and family history of diabetes did not increase the risk of hypertension. These results suggest that family history of hypertension has an additive impact on the age-associated increase in the risk of hypertension, whereas family history of diabetes has an exponential impact on aging-associated increase in the risk of diabetes.

Insulin resistance is associated with hypertensive response to exercise in non-diabetic hypertensive patients

AIM

Insulin resistance is associated with increased sympathetic activity and elevated angiotensin II which may contribute to the excessive increase in arterial blood pressure during exercise. In this study, we hypothesized that increased insulin resistance will be significantly associated with hypertensive response to exercise (HRE) in non-diabetic hypertensive patients.

METHOD

Two hundred seventy-five hypertensive patients were included in this study. HOMA-IR index using serum fasting glucose and insulin was calculated for insulin resistance. There were 79 patients with hypertensive response (age 56.1+/-9.4 years) and 196 patients without hypertensive response (age 53.9+/-8.9 years).

RESULTS

Insulin resistance, assessed by HOMA index, was significantly higher in hypertensive response group as compared to control (HOMA=2.60+/-1.54 versus 1.76+/-0.86, P<0.001). HOMA was an independent predictor of HRE when controlled for age, sex, BMI and baseline SBP (odds ratio=2.008, P<0.001). Also, HOMA was significantly correlated with the magnitude of SBP elevation controlled for age, sex, BMI and baseline SBP as well (beta=0.293, P<0.001). In conclusion, this study shows that insulin resistance is a significant determinant of hypertensive response to exercise. Further studies to determine the prognostic significance of this finding is warranted.

Insulin resistance is associated with arterial stiffness in nondiabetic hypertensives independent of metabolic status

We sought to determine whether insulin resistance (IR) is related to arterial stiffness in nondiabetic hypertensive patients, independent of metabolic status and gender. IR has been associated with increased arterial stiffness in patients with diabetes. In nondiabetic hypertensive patients, the correlation between IR and arterial stiffness has yet to be investigated. We enrolled 284 nondiabetic patients who were being treated for hypertension. At the time of enrollment, the patients underwent a baseline laboratory assessment including homeostatic model assessment (HOMA) IR index and pulse wave velocity (PWV). The HOMA IR index is used as a marker of IR, and brachial to ankle PWV (baPWV) was used as a marker of arterial stiffness. Of the 284 study subjects, 121 were classified as having metabolic syndrome. The patients with metabolic syndrome were older than the non-metabolic syndrome patients (55.4+/-10.7 vs. 52.1+/-11.6 years, p=0.013), but there was no gender difference between the two groups. The average baPWV was significantly higher in the patients with metabolic syndrome (1,506+/-235 vs. 1,435+/-211 cm/s, p=0.009). The HOMA index was independently associated with an increase in arterial stiffness (r=0.548, p<0.001) after controlling for age, systolic blood pressure (SBP), heart rate, medication and gender. The independent association of HOMA with arterial stiffness was demonstrated in subgroup analysis, regardless of the metabolic status and gender. In conclusion, increased IR was associated with arterial stiffness, independent of age, baseline SBP, gender and heart rate. This independent association of IR was demonstrated regardless of gender and metabolic status.

Relations of Insulin Sensitivity to Longitudinal Blood Pressure Tracking

Background— The relations of insulin sensitivity (IS) to hypertension incidence may vary according to baseline age, body mass index (BMI), and blood pressure (BP).

Methods and Results— We investigated the relations of IS (insulin sensitivity index, ISI 0,120 ) to 4-year incidence of hypertension and BP progression in 1933 nonhypertensive Framingham Study participants (median age, 51 years; 56% women). Analyses were stratified by age (less than versus greater than or equal to median), BMI (<25 [normal], 25 to <30 [overweight], ≥30 kg/m 2 [obese]), and BP category (systolic BP≥130 or diastolic BP≥85, “high normal” per the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High BP [JNC-VI] versus BP<130/85 mm Hg). On follow-up, 41% of participants had BP progression (≥1 BP stage increase) and 18% had development of hypertension (systolic BP≥140 or diastolic BP≥90 mm Hg or antihypertensive medication use). In younger (<51 years) people with normal BMI and baseline BP<130/85 mm Hg, the second-to-fourth ISI 0,120 quartiles were associated with lower multivariable-adjusted odds for hypertension incidence (0.27; 95% CI, 0.09 to 0.83; P <0.05) and BP progression (0.37; 95% CI, 0.18 to 0.77; P <0.01) relative to the lowest (most insulin resistant) quartile. IS was not related to BP progression or hypertension incidence in older individuals, in obese participants, or in people with BP≥130/85 mm Hg.

Conclusions— In our large community-based sample, reduced IS predicted BP tracking principally in younger people with normal BMI and BP<130/85 mm Hg. Effect modification by age, BMI, and baseline BP may explain variation in the results of prior clinical investigations relating IS to hypertension incidence.

Effects of leptin receptor gene 3'-untranslated region polymorphism on metabolic profiles in young Japanese men

We investigated the effects of leptin receptor gene 3'-untranslated region (3'-UTR) polymorphism on clinical and metabolic parameters in 221 young Japanese men aged 21 to 28 years. The polymerase chain reaction-restriction fragment length polymorphism method was used to identify a pentanucleotide (CTTTA) insertion in 3'-UTR of the leptin receptor gene. Body mass index, blood pressure, plasma glucose, insulin, leptin, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, free fatty acids, uric acid, apolipoprotein A-I (apoA-I), and cholesteryl-ester transfer protein levels were measured. There was only 1 homozygote and 38 heterozygotes for the 3'-UTR insertion allele among the 221 subjects. The insertion allele frequency was 0.090. Plasma HDL-cholesterol and apoA-I levels were significantly lower (p = 0.015 and p = 0.032 by Mann-Whitney U test, respectively) in homozygous or heterozygous carriers of the insertion allele than in subjects homozygous for the normal allele. There were no differences in other parameters measured. Furthermore, when the subjects were divided into three groups according to HDL-cholesterol level, the percentage of insertion allele-positive subjects was significantly lower in the highest HDL-cholesterol group (chi(2) = 8.42, p = 0.015). These findings suggest that serum HDL-cholesterol and apoA-I levels are influenced by the leptin receptor gene 3'-UTR polymorphism in young Japanese men.

Development and Progression of Atherosclerotic Disease in Relation to Insulin Resistance and Hyperinsulinemia

It is unclear whether the role of insulin resistance in the development of atherosclerotic cardiovascular disease is similar in populations in which the incidence of atherosclerotic diseases significantly differs from that in Western countries. The aim of this study was to determine the relationship between insulin resistance and the development of cardiovascular disease in the Japanese population. We conducted 75 g-oral glucose tolerance tests (OGTTs) on 1,928 inhabitants of two towns in Hokkaido, Japan. Subjects using antihypertensive agents and known diabetic patients were excluded from the study. Data from the remaining 1,227 subjects (540 males and 687 females; mean age 56.0 +/- 10.8 years) were used for the analysis, and 1,051 subjects were seen in a follow-up care setting for a period of 8 years. The presence of insulin resistance was defined according to the guidelines reported our previous study: insulin levels of 64.0 mU/l or higher 2 h after the 75 g-OGTT. The insulin-resistant (IR) group had several risk factors such as hypertension, diabetes, treated or untreated hypercholesterolemia, hypertriglyceridemia, low high-density-lipoprotein (HDL) cholesterol levels, and obesity. During the follow-up period of 8 years, the incidence of coronary artery disease, which was adjusted for age, body mass index, sex, systolic blood pressure, fasting plasma glucose, total cholesterol, triglyceride, and HDL cholesterol was significantly (3.2 times) higher in the IR group than in the insulin non-resistant group. The results suggested that insulin resistance is an independent risk factor for coronary artery disease in Japanese subjects, as has also been demonstrated in the case of individuals in Europe and USA.

Lower Birth Weight and Visceral Fat Accumulation Are Related to Hyperinsulinemia and Insulin Resistance in Obese Japanese Children

This study aimed to reveal the relation of birth weight (or the birth weight standard deviation score [BWSDS]) and visceral fat accumulation to hyperinsulinemia and insulin resistance. We examined obese Japanese children (650 boys and 317 girls) with a mean age of 10.3 years (range, 6-15 years). The mean percentage of overweight to the standard body weight of Japanese children was 52.1% in boys and 51.4% in girls. Abdominal fat thickness (maximum preperitoneal fat thickness; Pmax) was measured using ultrasonography. The fasting serum insulin and plasma glucose levels were measured, and the homeostasis model assessment-insulin resistance (HOMA-R) and quantitative insulin sensitivity check index (QUICKI) were calculated. We divided the subjects into four groups according to their birth weight or BWSDS, and compared anthropometric measurements, Pmax, blood pressure, serum insulin levels, HOMA-R and QUICKI among the quartiles. The relationships of both birth weight (or BWSDS) and Pmax to serum insulin levels (or HOMA-R, QUICKI) were examined with multiple regression analyses. The fasting serum insulin level and HOMA-R were highest in the quartile with the lowest birth weight or BWSDS. The birth weight and BWSDS were inversely related to the serum insulin levels and HOMA-R, positively related to QUICKI, and independent of Pmax. Our findings suggest that both lower birth weight and visceral fat accumulation may be independently related to hyperinsulinemia and insulin resistance in obese Japanese children.

Metabolic Syndrome and Cardiac Disease in Japanese Men: Applicability of the Concept of Metabolic Syndrome Defined by the National Cholesterol Education Program-Adult Treatment Panel III to Japanese Men-The Tanno and Sobetsu Study

Results of a 6-year follow-up study were used to determine whether the concept of and the criteria for metabolic syndrome as defined by the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) can be applied to Japanese men for prediction of the occurrence of cardiac disease. The subjects were 808 men who underwent mass health check-ups in 1993 and who were not on medication for hypertension, diabetes or hyperlipidemia. Individuals who had hypertriglyceridemia, hypo-high density lipoprotein (HDL) cholesterolemia, high blood pressure, and/or high fasting plasma glucose levels were identified on the basis of the NCEP-ATP III criteria. Not in conformity with the NCEP-ATP Ill, however, a cut-off value of 85 cm was used for waist girth as an indicator of abdominal obesity. The subjects who had 3 or more risk factors were judged as having metabolic syndrome. The proportion of subjects having metabolic syndrome was 25.3%. In the 6-year follow-up study, cardiac disease occurred in 11.7% of the subjects in the metabolic syndrome group and in 6.7% of the subjects in the non-metabolic syndrome group. Results of regression analysis using Cox's proportional hazards model showed that subjects in the metabolic syndrome group had a 2.2-times greater risk of developing cardiac disease than did subjects in the non-metabolic syndrome group. The concept of metabolic syndrome as defined in the NCEP-ATP III was therefore considered to be useful for predicting the occurrence of cardiac disease in Japanese men.

Thiazolidinedione Effects on Blood Pressure in Diabetic Patients with Metabolic Syndrome Treated with Glimepiride

The aim of our study was to compare the long-term effect of pioglitazone and rosiglitazone on blood pressure control of diabetic patients with metabolic syndrome treated with glimepiride. We evaluated 91 type 2 diabetic patients with metabolic syndrome. All were required to have been diagnosed as diabetic for at least 6 months, and to have failed to achieve glycemic control by dietary changes and the maximum tolerated dose of the oral hypoglycemic agents sulfonylureas or metformin. All patients took a fixed dose of 4 mg/day glimepiride. We administered pioglitazone (15 mg/day) or rosiglitazone (4 mg/day) for 12 months in a randomized, double-blind fashion, and evaluated body mass index (BMI), glycemic control, blood pressure and heart rate (HR) throughout the treatment period. A total of 87 patients completed the study and were randomized to receive double-blind treatment with pioglitazone or rosiglitazone. An increase in BMI was observed after 12 months (p < 0.05) in both groups. After 9 and 12 months, there were significant decreases in glycated hemoglobin (HbA(1c)), mean fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), and postprandial plasma insulin (PPI) in both treatment groups (p < 0.05 at 9 months and p < 0.01 at 12 months for all parameters). Furthermore, homeostasis model assessment index (HOMA index) improvement was obtained at 9 and 12 months (p < 0.05 and p < 0.01, respectively) in both groups. Significant systolic blood pressure (SBP) and diastolic blood pressure (DBP) improvement (p < 0.05, respectively) was observed in both groups after 12 months. There were no significant changes in transaminases at any point during the study. We can conclude that the association of a thiazolinedione to the glimepiride treatment of type 2 diabetic subjects with metabolic syndrome is associated to a significant improvement in the long-term blood pressure control, related to a reduction in insulin-resistance.

Usefulness of Serum Adiponectin Level as a Diagnostic Marker of Metabolic Syndrome in Obese Japanese Children

This study aimed 1) to investigate the relationship between serum adiponectin levels and metabolic disorders and 2) to clarify the usefulness of serum adiponectin level as a diagnostic marker of metabolic syndrome in obese Japanese children. One hundred obese boys aged 8 to 13 years were examined. Serum adiponectin levels were measured by radioimmunoassay using a commercial kit. Abdominal fat thickness (maximum preperitoneal fat thickness: P(max); minimum subcutaneous fat thickness: S(min)) was measured by ultrasonography. The relationships between adiponectin and clinical characteristics were analyzed by simple regression. The relationships between anthropometric measurements and metabolic disorders were analyzed among three groups divided according to adiponectin percentile. The prevalence of metabolic syndrome was also analyzed, with metabolic syndrome defined as the presence of three or more complications of obesity. The criteria for metabolic syndrome by adiponectin were subjected to a receiver operating characteristic (ROC) analysis. Body weight, waist circumference, P(max), alanine aminotransferase and fasting serum insulin were all inversely correlated with adiponectin. There were significant differences in the prevalence of severe obesity, the accumulation of visceral adipose tissue, hyperinsulinemia, high serum low density lipoprotein-cholesterol, the number of complications of obesity and the prevalence of metabolic syndrome among the three groups. The area under the ROC curve for adiponectin was 0.672 +/- 0.055 and the cut-off value was 6.65 microg/ml. Hypoadiponectinemia was associated with visceral fat accumulation and metabolic syndrome in obese Japanese boys. Evaluation of adiponectin might contribute to an early intervention for obese children with metabolic syndrome.

Fructose, glycemic load, and quantity and quality of carbohydrate in relation to plasma C-peptide concentrations in US women

BACKGROUND

Circulating C-peptide concentrations are associated with insulin resistance and the development of type 2 diabetes. However, associations between fructose and the quantity and quality of total carbohydrate intake in relation to C-peptide concentrations have not been adequately examined.

OBJECTIVE

We assessed the association of dietary fructose, glycemic load, and carbohydrate intake with fasting C-peptide concentrations.

DESIGN

Plasma C-peptide concentrations were measured in a cross-sectional setting in 1999 healthy women from the Nurses' Health Study I and II. Dietary fructose, glycemic load, and carbohydrate intake were assessed with the use of semiquantitative food-frequency questionnaires.

RESULTS

After multivariate adjustment, subjects in the highest quintile of energy-adjusted fructose intake had 13.9% higher C-peptide concentrations (P for trend = 0.01) than did subjects in the lowest quintile. Similarly, in the multivariate model, subjects in the highest quintile of glycemic load had 14.1% (P for trend = 0.09) and 16.1% (P for trend = 0.04) higher C-peptide concentrations than did subjects in the lowest quintile after further adjustment for total fat or carbohydrate intake, respectively. In contrast, subjects with high intakes of cereal fiber had 15.6% lower (P for trend = 0.03) C-peptide concentrations after control for other covariates.

CONCLUSIONS

Our results suggest that high intakes of fructose and high glycemic foods are associated with higher C-peptide concentrations, whereas consumption of carbohydrates high in fiber, such as whole-grain foods, is associated with lower C-peptide concentrations. Furthermore, our study suggests that these nutrients play divergent roles in the development of insulin resistance and type 2 diabetes.