The association of the insulin resistance syndrome with impaired glucose tolerance and NIDDM in the Japanese general population: the Hisayama study

Hematocrit and the risk of cardiovascular disease in a Japanese community: The Hisayama Study

OBJECTIVES

The association between hematocrit levels and the risk of cardiovascular disease (CVD) has been reported inconsistently. We aimed to investigate the association of hematocrit levels with the development of stroke and coronary heart disease (CHD) in a general Japanese population.

METHODS

A total of 2585 community-dwelling Japanese individuals aged 40 years or older in 1988 were followed up for 19 years. These subjects were divided into four groups according to the sex-specific quartiles of hematocrit at baseline.

RESULTS

During the follow-up, 301 subjects developed stroke (210 ischemic and 91 hemorrhagic) and 187 developed CHD. The risk of ischemic stroke was higher in both the lowest (Q1: men, ≤44.7%; women, ≤39.3%) and the highest (Q4: men, ≥49.7%; women, ≥43.8%) quartiles than in the third quartile (Q3: men, 47.1%-49.6%; women, 41.7%-43.7%) used as a reference (multivariable-adjusted hazard ratios [95% confidence intervals]: Q1, 1.55 [0.99-2.43]; Q2, 1.44 [0.93-2.23]; Q3, 1.00; and Q4, 1.62 [1.06-2.50]; P = 0.86 for trend). In contrast, hematocrit levels and the risk of hemorrhagic stroke showed a linear inverse association (Q1, 1.91 [1.03-3.54]; Q2, 1.26 [0.68-2.34]; Q3, 1.00; and Q4, 0.81 [0.41-1.61]; P = 0.009 for trend). The risk of CHD increased significantly in Q4 (Q1, 1.13 [0.71-1.80]; Q2, 1.08 [0.69-1.71]; Q3, 1.00; and Q4, 1.60 [1.04-2.46]; P = 0.13 for trend).

CONCLUSIONS

Our findings suggest that both elevated and decreased hematocrit levels are associated with an increased risk of CVD, but the influence of hematocrit is different among subtypes of CVD.

Insulin resistance and the development of cardiovascular disease in a Japanese community: the Hisayama study

AIMS

Although several surrogate measures of insulin resistance have been proposed, their associations with cardiovascular disease (CVD) have not been evaluated sufficiently.

METHODS

A total of 2,356 community-dwelling Japanese individuals aged 40 to 79 years who underwent a 75 g oral glucose tolerance test were followed up for 14 years. The status of insulin resistance was estimated by using the Matsuda index or homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

During follow-up, 260 subjects developed CVD. The age- and sex-adjusted hazard ratios of CVD significantly decreased with an increasing Matsuda index and rose with increasing HOMA-IR levels (both p for trend <0.05). After adjustment for age, sex, serum total cholesterol, electrocardiogram abnormalities, proteinuria, smoking habits, alcohol intake, and regular exercise, the risk of CVD was significantly lower in the third to fifth quintiles of the Matsuda index and higher in the fifth quintile of HOMA-IR values compared with the first quintile of the corresponding index (Matsuda index Q3: hazard ratio (HR)= 0.59 [95% confidence interval 0.40-0.87]; Q4: HR= 0.66 [0.45-0.97]; and Q5: HR= 0.67 [0.47-0.97]; HOMA-IR Q5: HR= 1.55 [1.05-2.29]); however, these associations were attenuated after further adjustment for the metabolic syndrome status. In regard to CVD subtypes, the risks for stroke and coronary heart disease significantly decreased with an increasing Matsuda index, while elevated HOMA-IR levels were a significant risk factor for stroke, but not for coronary heart disease.

CONCLUSION

Our findings suggest that insulin resistance significantly increases the risk of incident CVD through metabolic syndrome in Japanese.

Impact of diabetes among revascularized patients in Japan and the U.S

OBJECTIVE

Approximately 25% of patients who undergo percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) have diabetes, and the diagnosis of diabetes roughly doubles the mortality risk associated with coronary artery disease. However, the impact of diabetes may differ according to ethnicity. Our objective was to examine the impact of diabetes on long-term survival among U.S. and Japanese patients who underwent PCI or CABG.

RESEARCH DESIGN AND METHODS

For the current analysis, we included 8,871 patients from a Japanese multicenter registry (Coronary Revascularization Demonstrating Outcome database in Kyoto; median follow-up 3.5 years; interquartile range [IQR] 2.6-4.3) and 7,229 patients from a U.S. multipractice registry (Texas Heart Institute Research Database; median follow-up 5.2 years; IQR 3.8-6.5).

RESULTS

Diabetes was more prevalent among Japanese than U.S. patients (39.2 vs. 31.0%; P < 0.001). However, after revascularization, long-term all-cause mortality was lower in diabetic Japanese patients than in diabetic U.S. patients (85.4 vs. 82.2%; log-rank test P = 0.009), whereas it was similar in nondiabetic Japanese and U.S. patients (89.1 vs. 89.5%; P = 0.50). The national difference in crude mortality was also significant among insulin-using patients with diabetes (80.8 vs. 74.9%; P = 0.023). When long-term mortality was adjusted for known predictors, U.S. location was associated with greater long-term mortality risk than Japanese location among nondiabetic patients (hazard ratio 1.58 [95% CI 1.32-1.88]; P < 0.001) and, especially, diabetic patients (1.88 [1.54-2.30]; P < 0.001).

CONCLUSIONS

Although diabetes was less prevalent in U.S. patients than in Japanese patients, U.S. patients had higher overall long-term mortality risk. This difference was more pronounced in diabetic patients.

Comparison of three-year clinical outcomes after sirolimus-eluting stent implantation among insulin-treated diabetic, non-insulin-treated diabetic, and non-diabetic patients from j-Cypher registry

The purpose of the present study was to evaluate the 3-year clinical outcomes after percutaneous coronary intervention with sirolimus-eluting stents in patients with insulin-treated diabetes mellitus (DM-insulin) and those with non-insulin-treated DM (DM-non-insulin) compared to patients without DM. Of 10,778 consecutive patients treated exclusively with sirolimus-eluting stents in the j-Cypher registry, we identified 996 patients with DM-insulin, 3,404 with DM-non-insulin, and 6,378 without DM. Compared to the non-DM group, the adjusted risk of a serious cardiovascular event (composite of all-cause death, myocardial infarction, and stroke) was significantly greater in the DM-insulin group (hazard ratio 1.12, 95% confidence interval [CI] 1.03 to 1.23; p = 0.01), but not in the DM-non-insulin group (hazard ratio 1.02, 95% CI 0.96 to 1.09; p = 0.47). The adjusted risk of target lesion revascularization was significantly greater in both the DM-insulin group (odds ratio 1.52, 95% CI 1.19 to 1.92; p = 0.0006) and the DM-non-insulin group (odds ratio 1.24, 95% CI 1.05 to 1.45; p = 0.009). In conclusion, a diabetes-associated excess risk of target lesion revascularization was found, regardless of insulin use in this large, real-world study of Japanese patients with sirolimus-eluting stent implantation. However, regarding serious cardiovascular events, an excess risk was seen only in the DM-insulin group. The risk of serious cardiovascular events was similar between the DM-non-insulin and non-DM groups.

Visceral fat is a strong predictor of insulin resistance regardless of cardiorespiratory fitness in non-diabetic people

Abdominal adiposity and low cardiorespiratory fitness are associated with insulin resistance in people with impaired glucose tolerance and type 2 diabetes. However, little is known about which factor precedes insulin resistance in people with impaired glucose tolerance and type 2 diabetes, and which is the stronger predictor of insulin resistance in non-diabetic people. The purpose of this study was to examine the relationship between insulin resistance and cardiorespiratory fitness, visceral fat, and subcutaneous fat in non-diabetic people. Subjects included 87 men and 77 women aged 30-72 y (mean+/-SD, 51.3+/-12.3 y). Cardiorespiratory fitness was assessed by measuring the maximal oxygen uptake (VO2max) in a progressive continuous test to exhaustion on a cycle ergometer. The visceral and subcutaneous fat areas were measured by magnetic resonance imaging. The homeostasis model assessment of insulin resistance (HOMA-R) was calculated from the fasting concentrations of glucose and insulin. Stepwise multiple linear regression analysis revealed that visceral and subcutaneous fat were significant correlates of HOMA-R, explaining 24% and 6% of the variance, respectively, whereas sex, age, and VO2max were not significant independent determinants. Abdominal fat deposition rather than cardiorespiratory fitness is a significant predictor of insulin resistance in non-diabetic people; visceral fat is the most important factor.

Impact of blood pressure levels on different types of stroke: the Hisayama study

OBJECTIVE

Clinical uncertainty remains whether the blood pressure classification and risk stratifications recommended by the Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2009) are useful in predicting the risks of stroke and its subtypes in the general Japanese population.

METHODS

A total of 1621 stroke-free residents of a Japanese community aged at least 40 years were followed up for 32 years. Outcomes were total and cause-specific stroke (lacunar infarction, atherothrombotic infarction, cardioembolic infarction, cerebral haemorrhage and subarachnoid haemorrhage). Incidence was calculated by the pooling of repeated observations method.

RESULTS

The age-adjusted incidence of total stroke rose progressively with higher blood pressure levels in both sexes (both P for trend <0.0001). A similar pattern was observed for lacunar infarction in both sexes and for cerebral haemorrhage in men: the differences were significant between optimal blood pressure and grades 1-3 hypertension (all P < 0.05). The age-adjusted incidence of atherothrombotic infarction in either sex and that of cardioembolic infarction and subarachnoid haemorrhage in women significantly increased in grade 3 hypertension (all P < 0.05). These associations remained substantially unchanged even after adjustment for other risk factors. In regard to risk stratification, the age-adjusted incidence of stroke significantly increased with the level of risk in both sexes.

CONCLUSION

Our findings suggest that the blood pressure classification and risk stratifications recommended by the JSH 2009 guidelines are useful in predicting the risk of stroke in a general Japanese population, but the magnitude and patterns of the impact of blood pressure categories are different among stroke subtypes.

The association of intensity and overall level of physical activity energy expenditure with a marker of insulin resistance

AIMS/HYPOTHESIS

Physical activity is important in preventing insulin resistance, but it is unclear which dimension of activity confers this benefit. We examined the association of overall level and intensity of physical activity with fasting insulin level, a marker of insulin resistance.

METHODS

This was a cross-sectional analysis of the Medical Research Council Ely population-based cohort study (2000--2002). Physical activity energy expenditure (PAEE) in kJ kg(-1) min(-1) was measured by heart rate monitoring with individual calibration over a period of 4 days. The percentage of time spent above 1.5, 1.75 and 2 times resting heart rate (RHR) represented all light-to-vigorous, moderate-to-vigorous and vigorous activity, respectively.

RESULTS

Data from a total of 643 non-diabetic individuals (319 men, 324 women) aged 50 to 75 years were analysed. In multivariate linear regression analyses, adjusting for age, sex and body fat percentage, PAEE was significantly associated with fasting insulin (pmol/l) (beta = -0.875, p = 0.006). Time (% of total) spent above 1.75 x RHR and also time spent above 2 x RHR were both significantly associated with fasting insulin (beta = -0.0109, p = 0.007 and beta = -0.0365, p = 0.001 respectively), after adjusting for PAEE, age, sex and body fat percentage. Time spent above 1.5 x RHR was not significantly associated with fasting insulin in a similar model (beta = -0.0026, p = 0.137).

CONCLUSIONS/INTERPRETATION

The association between PAEE and fasting insulin level, a marker of insulin resistance, may be attributable to the time spent in moderate-to-vigorous and vigorous activity, but not to time spent in light-intensity physical activity.

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 Influence of Current and Former Smoking on Gingival Bleeding: The Hisayama Study

BACKGROUND

Previous studies have shown that smoking is a risk factor for periodontitis and that it has a suppressive effect on gingival bleeding. This study examined the relationship between smoking, including past smoking, and periodontal conditions, mainly gingival bleeding, in a community-based health investigation.

METHODS

Smoking status was examined in 958 subjects, along with the quantity of tobacco currently or previously smoked (never, former light, former heavy, current light, and current heavy). We analyzed the influence of smoking on probing depth (PD), clinical attachment loss (CAL), and gingival bleeding on probing (BOP).

RESULTS

In multivariate logistic regression analyses, current heavy smokers were at a significantly greater risk for having a higher proportion of teeth with PD > or =4 mm and a higher proportion of teeth with CAL > or =5 mm; however, they had a lower risk for having a high BOP than did those who had never smoked. Moreover, both former light and former heavy smokers had significantly lower risks for high BOP. When the analysis was limited to subjects with PD > or =4 mm, former heavy and current heavy smokers showed a significant suppression of high BOP compared to never smokers.

CONCLUSION

This study suggests that smoking is significantly associated with PD and CAL and that current and past smoking has a suppressive effect on BOP.

Insulin secretion and insulin sensitivity in Japanese subjects with impaired fasting glucose and isolated fasting hyperglycemia

Impaired fasting glucose (IFG) is a subgroup of impaired glucose regulation exhibiting an elevated fasting glucose levels without elevated 2-h glucose levels on oral glucose tolerance test (OGTT). Diabetes mellitus with isolated fasting hyperglycemia (DM/IFH) is a similar subgroup of diabetes having higher fasting glucose levels with 2-h glucose levels within the non-diabetic range. The aim of this study is to profile the characteristics of these subgroups to estimate the factors involved in the development from normal glucose tolerance (NGT) via IFG to DM/IFH. Five hundred and sixty seven Japanese males were classified on the basis of 75 g OGTT into four groups, NGT, IFG, DM/IFH, and isolated impaired glucose tolerance (isolated IGT). Insulin secretion was evaluated by insulinogenic index, insulin sensitivity was evaluated by ISI composite, and insulin secretory patterns were compared additionally. IFG and DM/IFH subjects exhibited both lower insulin secretion and lower insulin sensitivity than NGT subjects. There was an insulin peak in NGT, IFG, and DM/IFH at 60 min, which did not occur in isolated IGT. Impaired early-phase and basal insulin secretion and decreased insulin sensitivity both are estimated as factors in progression from NGT via IFG to DM/IFH in these subjects. IFG and DM/IFH subjects have definite fasting hyperglycemia in contrast to isolated IGT subjects, 2-h glucose levels being maintained within the non-diabetic range partly by the insulin peak at 60 min.

Comparison of diagnostic methods for diabetes mellitus based on prevalence of retinopathy in a Japanese population: the Hisayama Study

AIMS/HYPOTHESIS

The aims of this study were to compare the ability of tests measuring fasting plasma glucose, 2-h plasma glucose and HbA1c levels in predicting specific diabetic retinopathy, and to determine the cut-off level of each measurement for diagnosing diabetes in a Japanese population.

METHODS

In a total of 1637 subjects, fasting plasma glucose, 2-h plasma glucose and HbA1c levels were measured in a 75-g oral glucose tolerance test, and diabetic retinopathy was assessed by ophthalmic examination. We calculated receiver operating characteristic (ROC) curves as well as the prevalence of diabetic retinopathy by deciles of the distribution of these glycaemic measurements.

RESULTS

Of the subjects, 37 (2.3%) had diabetic retinopathy. The prevalence of retinopathy dramatically increased in the tenth decile of each variable. Analysis with ROC curves showed that the optimal cut-off levels for diagnosis of diabetes were 6.4 mmol/l for fasting plasma glucose, 11.1 mmol/l for 2-h plasma glucose, and 5.7% for HbA1c. The sensitivities for the cut-off point of the three measurements were identical (86.5%), and the specificities were similar (fasting plasma glucose 87.3%; 2-h plasma glucose 89.6%; HbA1c 90.1%). The area under the ROC curve for 2-h plasma glucose (96.1%) was slightly but not significantly larger than that for fasting plasma glucose (90.0%) and that for HbA1c (94.5%).

CONCLUSIONS/INTERPRETATION

. Our findings suggest that measuring fasting plasma glucose or HbA1c is just as useful as measuring 2-h plasma glucose for the diagnosis of diabetes, and that the cut-off point for diagnostic fasting plasma glucose level is lower than that of the current diagnostic criteria.

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.

Factors responsible for development from normal glucose tolerance to isolated postchallenge hyperglycemia

OBJECTIVE

Isolated postchallenge hyperglycemia (IPH), defined as fasting plasma glucose (FPG) level <7.0 mmol/l and 2-h plasma glucose (PG) level >/=11.1 mmol/l, is a subtype of early-stage diabetes. This study evaluates the metabolic profiles of insulin secretion and insulin sensitivity in IPH to clarify the factors responsible for development of this form of type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted cross-sectional analysis of 231 Japanese men aged 20-70 years. The subjects were classified into the following three groups, based on the results of a 75-g oral glucose tolerance test (OGTT): 1) normal glucose tolerance (NGT), defined as FPG level <6.1 mmol/l and 2-h PG level <7.8 mmol/l (n = 89); 2) impaired glucose tolerance (IGT), defined as FPG level <7.0 mmol/l and 2-h PG level of 7.8-11.1 mmol/l (n = 94); and 3) IPH (n = 48). We compared the three groups for insulin secretion (insulinogenic index) and insulin sensitivity (index of insulin resistance using homeostasis model assessment [HOMA-IR]).

RESULTS

The insulinogenic index in IPH was the lowest of the three groups (P < 0.001 versus NGT). The HOMA-IR in the IGT and IPH groups were significantly higher than in the NGT group (P < 0.001), but both were similar. By linear regression analysis, the insulinogenic index rather than fasting insulin or HOMA-IR was the more significant factor in the 2-h PG level in IGT and IPH.

CONCLUSIONS

Subjects with IPH exhibited distinctly impaired early-phase insulin secretion and only mild insulin resistance, indicating that reduced insulin secretion is the primary determinant of deterioration from NGT to IGT and IPH in development of type 2 diabetes in these subjects.

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.

Incidence and risk factors for subtypes of cerebral infarction in a general population: the Hisayama study

BACKGROUND AND PURPOSE

We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan.

METHODS

Stroke-free subjects (n=1621) aged >/=40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings.

RESULTS

The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0. 7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox's proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depression on ECG, glucose intolerance, and smoking in men and left ventricular hypertrophy on ECG and body mass index in women remained significant risk factors for lacunar infarction. ST depression was also significantly related to events of atherothrombotic infarction in women. The risk of atrial fibrillation for cardioembolic infarction was outstandingly high in both sexes, and left ventricular hypertrophy and lower total cholesterol were additional risk factors for cardioembolic infarction in women.

CONCLUSIONS

In this Japanese population, lacunar infarction was the most common subtype of cerebral infarction and had a greater variety of risk factors, including not only hypertension but also ECG abnormalities, diabetes, obesity, and smoking, than did atherothrombotic infarction or cardioembolic infarction.

Waist to hip ratio, body mass index, and glucose intolerance from Funagata population-based diabetes survey in Japan

To examine the association of body mass index (BMI) and waist-to-hip ratio (WHR) with glucose intolerance among adults age 45 and over, we conducted a population-based study using an oral glucose tolerance test as a primary examination in two areas of Funagata, Japan, in 1990 and 1992. The number of eligible subjects was 1673. The participation rate was 84% (1408/1673). Glucose tolerance was assessed by the 1985 World Health Organization criteria as having diabetes (DM), impaired glucose tolerance (IGT), or normal glucose tolerance (NGT). Analyses by the generalized linear model revealed that both BMI and WHR were higher in the subjects with DM and IGT than those with NGT in both men and women after controlling for age. Analyses employing multiple logistic regression indicated that BMI and WHR were independently associated with IGT and DM in both men and women, except for BMI with IGT for men. The odds ratios for IGT associated with BMI were 1.06 (p=0.19) for men and 1.11 (p<0.01) for women. Those associated with WHR were 2.14 (p<0.01) for men and 1.35 (p<0.01) for women. These results imply that WHR plays an important role for developing DM independent of BMI.

Epidemiology of non-insulin-dependent diabetes mellitus and its macrovascular complications. A basis for the development of cost-effective programs

Non-insulin-dependent diabetes mellitus is a major health problem in developed countries. The descriptive epidemiology of this disease and its cardiovascular complications are reviewed, and insulin resistance is identified as a common risk factor for both of them. The requirements for cost-effective programs to modify insulin resistance to prevent this disorder and its cardiovascular complications are discussed.

Association between hyperinsulinemia and intima-media thickness of the carotid artery in normotensive men

OBJECTIVES

To determine whether hyperinsulinemia is associated with early atherosclerosis in normotensive men of a work site population.

DESIGN AND METHODS

Six hundred and seventeen subjects were screened from 8678 male transport workers for the further examination of cardiovascular disease and diabetes. Subjects aged less than 40 years, those with hypertension or diabetes, or both, and those being administered medications for hyperlipidemia were excluded. Finally, 164 normotensive, nondiabetic subjects were enrolled. The intima-media thickness (IMT) was measured by B-mode ultrasonography with a 7.5 MHz probe. Electrocardiography, a 75 g oral glucose-tolerance test (OGTT) and blood chemistry measurements were also performed. The sum of insulin values (sigmaIRI) and the ratio of the sum of insulin values to blood glucose levels (sigmaIRI/sigmaBG) in the 75 g OGTT were used as markers of hyperinsulinemia.

RESULTS

The mean age of the subjects was 52 +/- 5 years (mean +/- SD). In a univariate analysis, IMT was associated with age, systolic blood pressure, body mass index, sigmaIRI, and sigmaIRI/sigmaBG. Multivariate analysis showed that age, total cholesterol, and sigmaIRI (or sigmaIRI/sigmaBG) were independent risk factors for IMT.

CONCLUSIONS

These results suggest that, in addition to age and total cholesterol, hyperinsulinemia as assessed by an OGTT is associated with early atherosclerosis in normotensive, nondiabetic men of a work site population.

Distribution and correlates of insulin in elderly men. The Honolulu Heart Program

The role of insulin in cardiovascular disease is uncertain, and studies in elderly or minority populations are infrequent. Fasting and 2-hour insulin concentrations and their cross-sectional associations with cardiovascular risk factors were examined in 3562 elderly (aged 71 to 93 years) Japanese American men from the Honolulu Heart Program who were reexamined between 1991 and 1993. Insulin distributions were skewed (mean and median: 16.8 and 12 microU/mL for fasting; 117.2 and 93 microU/mL for 2-hour); fasting but not 2-hour insulin levels declined significantly with age (P < .0001 and P = .54, respectively). Factors most strongly correlated with insulin included measures of obesity, fat distribution, and levels of triglyceride, glucose (r = .38 to r = .50 fasting, r = .21 to r = .27 2-hour), and HDL cholesterol (r = -.41 and r = -.22, respectively). Other correlates included fibrinogen, hematocrit, heart rate, blood pressure, cigarettes per day (all positive), alcohol, physical activity, and forced vital capacity (negative). Associations were also evident across risk factor quintiles. Insulin levels were significantly elevated in men with hypertension and diabetes. In multiple linear regression analyses, log10 fasting insulin was positively and independently associated with body mass index, triglycerides, glucose, fibrinogen, hematocrit, heart rate, diabetes, and hypertension and negatively associated with HDL cholesterol, physical activity, and forced vital capacity. In general, results were similar for log10 2-hour insulin and when subjects who fasted < 12 hours or had diabetes were excluded. Substitution of medication use and blood pressure for hypertension indicated independent associations of medication use but not blood pressure with insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

The NSY mouse: a new animal model of spontaneous NIDDM with moderate obesity

The NSY (Nagoya-Shibata-Yasuda) mouse was established as an inbred strain of mouse with spontaneous development of diabetes mellitus, by selective breeding for glucose intolerance from outbred Jcl:ICR mice. NSY mice spontaneously develop diabetes mellitus in an age-dependent manner. The cumulative incidence of diabetes is 98% in males and 31% in females at 48 weeks of age. Neither severe obesity nor extreme hyperinsulinaemia is observed at any age in these mice. Glucose-stimulated insulin secretion was markedly impaired in NSY mice after 24 weeks of age. In contrast, fasting plasma insulin level was higher in male NSY mice than that in male C3H/He mice (545 +/- 73 vs 350 +/- 40 pmol/l, p < 0.05, at 36 weeks of age). Pancreatic insulin content was higher in male NSY mice than that in male C3H/He mice (76 +/- 8 vs 52 +/- 5 ng/mg wet weight, p < 0.05, at 36 weeks of age). Morphologically, no abnormal findings, such as hypertrophy or inflammatory changes in the pancreatic islets, were observed in NSY mice at any age. These data suggest that functional changes of insulin secretion in response to glucose from pancreatic beta cells may contribute to the development of non-insulin-dependent diabetes mellitus (NIDDM) in the NSY mouse. Although insulin sensitivity was not measured, fasting hyperinsulinaemia in NSY mice suggests that insulin resistance may also contribute to the pathogenesis of NIDDM. Since these findings are similar to the pathophysiologic features of human NIDDM patients, the NSY mouse is considered to be useful for investigating the pathogenesis and genetic predisposition to NIDDM.