Trends in hyperinsulinemia among nondiabetic adults in the U.S

OBJECTIVE

Insulin resistance and compensatory hyperinsulinemia have been proposed as increasing risk for a variety of abnormalities and clinical syndromes, including type 2 diabetes and cardiovascular disease. Our aim was to assess the trends in the mean concentrations of fasting serum insulin and the prevalence of hyperinsulinemia among nondiabetic adults during the periods of 1988-1994 and 1999-2002 in the U.S.

RESEARCH DESIGN AND METHODS

We conducted analyses of data among men and nonpregnant women without diabetes aged >/=20 years from the Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994; n = 7,926) and NHANES 1999-2002 (n = 2,993). Both surveys were designed to represent the noninstitutionalized civilian U.S. population. We calculated age-adjusted mean concentrations of fasting insulin and the prevalence of hyperinsulinemia defined using the 75th percentile of fasting insulin among nondiabetic individuals as the cutoff value.

RESULTS

The geometric mean concentrations of fasting insulin increased by approximately 5% from 1988-1994 to 1999-2002 among nondiabetic adults aged >/=20 years in the U.S. Mexican-American men, men and women aged 20-39 years, and non-Hispanic white women had a greater relative increase in the mean concentrations of fasting insulin than their counterparts. The prevalence of hyperinsulinemia increased by 35.1% overall (38.3% among men and 32.1% among women).

CONCLUSIONS

In parallel with the obesity epidemic, concentrations of fasting insulin and prevalence of hyperinsulinemia have increased remarkably among nondiabetic U.S. adults.

Serum cholesteryl fatty acid composition and plasma glucose concentrations in Amerindian women

BACKGROUND

Diabetes mellitus has reached epidemic proportions in women of Amerindian origin. The risk of developing diabetes has been found to be related to the serum fatty acid composition in whites.

OBJECTIVE

We prospectively investigated the relation between the serum cholesteryl fatty acid composition and changes in fasting plasma glucose concentrations in Peruvian Indian women who are characterized by hyperinsulinemia in comparison to white women.

DESIGN

A 5-y follow-up study of 73 women with normal fasting plasma glucose values was undertaken by performing a survey in 1999 and a follow-up survey in 2004. The studied variables included anthropometric measurements, plasma insulin and leptin, dietary food consumption from 24-h recall, blood pressure, and serum fatty acid composition.

RESULTS

The participants developed significantly higher fasting plasma glucose concentrations in 2004 compared with 1999 (P < 0.0001) with unaltered plasma insulin values. Palmitoleic acid (16:1n-7) in 1999 was the only fatty acid that was significantly correlated to glucose concentration at follow-up. In a multiple regression analysis that included waist circumference, percentage of body fat, systolic blood pressure, and circulating triacylglycerol, insulin, leptin, and 16:1n-7 as independent determinants, 16:1n-7 and systolic blood pressure were the only significant determinants of plasma glucose concentration 5 y later.

CONCLUSIONS

A high proportion of 16:1n-7 in serum is an independent predictor of high plasma glucose concentrations in Amerindian women. The reason for this association remains to be elucidated.

Hyperinsulinemia, impaired glucose tolerance, and diabetes mellitus in survivors of childhood cancer: prevalence and risk factors

CONTEXT

Hyperinsulinism and its associated metabolic abnormalities, including diabetes mellitus (DM), have been reported in long-term survivors of childhood cancer, mainly after bone marrow transplant (BMT); however, the predisposing factors are unclear, and early markers have not been identified.

METHODS

The prevalence of overweight/obesity, abdominal adiposity and hyperinsulinemia (HI), impaired glucose tolerance (IGT), or DM was examined prospectively in 248 survivors of childhood cancer (36 prepubertal, 88 pubertal, and 124 adult subjects; 67 BMT) at a median of 12.9 yr (2.3-33.6) after diagnosis and compared with healthy controls. Potential risk factors for the development of HI, IGT, or DM were sought.

RESULTS

Overweight/obesity was not increased when comparing subjects with controls; however, the prevalence of abdominal adiposity in prepubertal and pubertal subjects was roughly doubled (P < or = 0.04). Fasting insulin concentrations were higher in prepubertal and pubertal subjects compared with their controls (P < 0.001) and were similar in adult and pubertal subjects. HI, IGT, or DM was detected in 39 of 212 (18%) pubertal or adult subjects (23 BMT). Ten of 88 (11%) pubertal and 14 of 124 (11%) adult subjects had IGT/DM (vs. 0 and 4.9% controls, respectively; P < 0.001). Total body irradiation, untreated hypogonadism, and abdominal adiposity emerged as independent risk factors for the development of HI, IGT, or DM in multivariate regression analysis.

CONCLUSIONS

The risk factors identified suggest the need for reconsideration of BMT protocols and regular screening of survivors. The increased prevalence of abdominal adiposity among prepubertal subjects, none of whom had developed HI/IGT/DM, suggests that a waist to height ratio greater than 0.5 has potential as a clinical screening tool.

Hyperinsulinemia in healthy children and adolescents with a positive family history for type 2 diabetes

OBJECTIVE

Our goal was to determine the relationship between family history of type 2 diabetes and fasting hyperinsulinemia in healthy children and adolescents.

METHODS

A total of 317 children and adolescents, 10 to 14 years of age with Tanner stage 1 or 2, were randomly selected from elementary and middle schools in Durango, northern Mexico, to participate in a cross-sectional, community-based study. Family history was ascertained by a direct, detailed medical examination that included anthropometric and laboratory measurements from both parents. We determined the prevalence of family history of type 2 diabetes, high blood pressure, obesity, hyperinsulinemia, and the adjusted odds ratio that computes the relationship between hyperinsulinemia and family history of type 2 diabetes.

RESULTS

Family history of type 2 diabetes, high blood pressure, and obesity was recognized in 30 (9.2%), 61 (18.7%), and 74 (22.7%) children and adolescents, respectively. Children and adolescents with positive family history showed higher systolic and diastolic blood pressure, were more obese, and exhibited significantly higher fasting insulin and triglycerides levels, as well as a higher homeostasis model analysis insulin resistance index, than children with negative family history. A total of 48 (15.1%) children and adolescents exhibited hyperinsulinemia, 35 (72.9%) with and 13 (27.1%) without family history. The odds ratio adjusted by gender, fat mass (kilograms and percent), waist circumference, BMI, and Tanner stage showed that family history of diabetes, but not high blood pressure and obesity, was independently related with hyperinsulinemia.

CONCLUSIONS

Among children and adolescents, family history of diabetes, but not high blood pressure and obesity, is independently associated with hyperinsulinemia.

Hyperinsulinemia is an independent predictor for complex atherosclerotic lesion of thoracic aorta in non-diabetic patients

OBJECTIVE

Hyperinsulinemia is a well known risk factor for cardiovascular event. However, it is not known whether hyperinsulinemia facilitates atherosclerotic complex lesions of aorta in non-diabetic patients. We investigated whether hyperinsulinemia is an independent marker of severity of atherosclerosis in thoracic aorta of non-diabetic patients using multiplane transesophageal echocardiography (TEE).

RESEARCH DESIGN AND METHODS

Non-diabetic 90 patients with cardiovascular disease underwent TEE, and were analyzed for plasma insulin levels of oral glucose tolerance test, conventional atherosclerotic risk factors and coronary angiographic features.

RESULTS

Thoracic aortic plaques were detected in 84 patients (93%). The complex atherosclerotic lesions were observed in 35 (39%) patients, most frequently at the part of aortic arch (p<0.005), showing the greatest atheroma score in thoracic aorta (p<0.05). Univariate analysis showed age, male gender, smoking, coronary artery disease, HDL-cholesterol, insulin levels in glucose tolerance test and homeostasis model assessment insulin resistance index (HOMA index) were found to be significant predictors of complex atherosclerotic lesions. Multivariate regression analysis revealed that HOMA index was an independent predictor of complex atherosclerotic lesions (odds ratio 1.93, p=0.006). There was a significant positive correlation between HOMA index and the atheroma score of thoracic aorta (p<0.001).

CONCLUSIONS

Hyperinsulinemia is an independent predictor of complex atherosclerotic lesions detected by TEE in the thoracic aorta of non-diabetic patients.

Liver steatosis coexists with myocardial insulin resistance and coronary dysfunction in patients with type 2 diabetes

Nonalcoholic fatty liver (NAFL) is a common comorbidity in patients with type 2 diabetes and links to the risk of coronary syndromes. The aim was to determine the manifestations of metabolic syndrome in different organs in patients with liver steatosis. We studied 55 type 2 diabetic patients with coronary artery disease using positron emission tomography. Myocardial perfusion was measured with [15O]H2O and myocardial and skeletal muscle glucose uptake with 2-deoxy-2-[18F]fluoro-D-glucose during hyperinsulinemic euglycemia. Liver fat content was determined by magnetic resonance proton spectroscopy. Patients were divided on the basis of their median (8%) into two groups with low (4.6 +/- 2.0%) and high (17.4 +/- 8.0%) liver fat content. The groups were well matched for age, BMI, and fasting plasma glucose. In addition to insulin resistance at the whole body level (P = 0.012) and muscle (P = 0.002), the high liver fat group had lower insulin-stimulated myocardial glucose uptake (P = 0.040) and glucose extraction rate (P = 0.0006) compared with the low liver fat group. In multiple regression analysis, liver fat content was the most significant explanatory variable for myocardial insulin resistance. In addition, the high liver fat group had increased concentrations of high sensitivity C-reactive protein, soluble forms of E-selectin, vascular adhesion protein-1, and intercellular adhesion molecule-1 (P < 0.05) and lower coronary flow reserve (P = 0.02) compared with the low liver fat group. In conclusion, in patients with type 2 diabetes and coronary artery disease, liver fat content is a novel independent indicator of myocardial insulin resistance and reduced coronary functional capacity. Further studies will reveal the effect of hepatic fat reduction on myocardial metabolism and coronary function.

[Epidemiological feature of metabolic syndrome in Shanghai residents aged 15 - 74 years]

OBJECTIVE

To assess the prevalence of the metabolic syndrome in Shanghai residents.

METHODS

A cross-sectional study was conducted in Shanghai with a representative sample of 14,327 Chinese adults from 15 to 74 years of age. The sample was randomly selected using stratified cluster sampling. The criteria of International Diabetes Federation (IDF), the US National Cholesterol Education Program Adult Treatment Panel III (ATP III) guidelines and the China Diabetes Society (CDS), respectively, were applied for diagnosis.

RESULTS

Diagnosed by using the IDF criterion, the crude prevalence of metabolic syndrome was 17.51%, and the age and gender-adjusted prevalence was 12.81% (95% CI: 12.26 - 13.36). The prevalence of the metabolic syndrome was higher in females than in males (14.79% and 10.93%, respectively), and higher in urban residents than in rural ones (13.71% and 10.72%, respectively). The age-specific prevalence of the metabolic syndrome increased in both male and female residents and the prevalence of metabolic syndrome in females 45 years of age or elder was significantly increased. The prevalence of having at least 3 parameters of metabolic syndrome was 22.28%. According to the ATP III guideline, the crude and age-adjusted prevalence of metabolic syndrome was 12.03% and 8.62%, respectively. Based on the criterion of CDS, they were 13.98% and 10.41%.

CONCLUSION

There is a high prevalence of metabolic syndrome in Shanghai residents. Metabolic syndrome has become a noteworthy public health problem. It suggests that community-integrated control of metabolic syndrome should have its priority.

Clinical Outcomes in Metabolic Syndrome

Metabolic syndrome is a clustering of cardiovascular risk factors. Its definition is the presence of any 3 of the following: obesity, hypertriglyceridemia, low high-density lipoprotein, hypertension, and impaired fasting glucose. The development of coronary artery disease is the most dreaded complication of this disease. In the United States, Mexican Americans and African American women are the most affected. Management of this syndrome includes physical exercise, weight loss, and effective drug treatment of dyslipidemia, high blood pressure, and impaired fasting blood glucose. Because of the increasing prevalence of obesity and diabetes, there is a rise in fatal and nonfatal cardiovascular events. With the development of effective antiplatelet medication and newer drug-eluting stents, percutaneous coronary intervention has become an effective revascularization strategy for those with coronary artery disease. Rates of stent restenosis and target-lesion revascularization have been reduced. Oral hypoglycemic drugs like thiazolidinediones improve insulin resistance and may have a favorable effect in those with metabolic syndrome. Diagnosis and appropriate management of metabolic syndrome are challenges as the presence of risk factors predates the coronary event.

Failure of the homeostatic model assessment calculation score for detecting metabolic deterioration in young patients with polycystic ovary syndrome

OBJECTIVE

To verify whether the homeostatic model assessment (HOMA) test is a suitable method for the identification of metabolic deterioration in normal-weight patients affected by polycystic ovary syndrome (PCOS).

DESIGN

Prospective clinical study.

SETTING

Academic clinic and research environment in Cagliari, Italy.

PATIENT(S)

Forty-nine PCOS normal-weight adolescent subjects, and 50 eumenorrheic, normal-weight, nonhirsute controls matched for age and body mass index (BMI).

INTERVENTION(S)

History and physical examination, oral glucose tolerance test (OGTT) and blood sampling, ultrasound.

MAIN OUTCOME MEASURE(S)

The HOMA score and integrated secretory area under the curve of insulin values (I-AUC) during the OGTT were calculated.

RESULT(S)

Normal insulin sensitivity was defined as upper control 95th percentile by HOMA values <65.6, I-AUC at 180 minutes <16,921, and I-AUC at 120 minutes <11,817. When applying the calculated I-AUC cutoff, 27 PCOS patients were classified as normoinsulinemic and 22 as hyperinsulinemic, whereas using the calculated HOMA cutoff, only 9 PCOS patients could be classified as insulin resistant (IR). Thirteen of the 40 non-IR PCOS patients presented with hyperinsulinemia; fasting glucose and insulin levels and HOMA scores were not sufficient to identify these subjects. Thus, the HOMA test displayed a low sensitivity (41%) and specificity (100%) in the diagnosis of the metabolic disorder disclosed by I-AUC. Moreover, analysis of I-AUC after 120 and 180 minutes revealed how the shorter evaluation period did not suffice for identification of all hyperinsulinemic subjects, implying an unrecognized condition in 11 of 22 subjects.

CONCLUSION(S)

In young, normal-weight patients with PCOS, the prevalence of hyperinsulinemia is not detectable by HOMA studies. The prevalence of IR was 18% according to HOMA evaluation, whereas hyperinsulinemia was found in 44% of subjects examined by I-AUC. Normal-weight, young PCOS patients should undergo a 3-hour OGTT to detect early metabolic abnormalities.

Obesity and Insulin Resistance As Risk Factors for Chronic Kidney Disease

The cardiometabolic syndrome is a state of metabolic and vascular dysregulation. The cardiometabolic syndrome is clinically composed of a cluster of metabolic abnormalities including insulin resistance/hyperinsulinemia, central/visceral obesity, dyslipidemia, hypertension, microalbuminuria, fibrinolytic and inflammatory abnormalities, endothelial dysfunction, oxidative stress, and hypercoagulability, which collectively lead to an increased risk of cardiovascular and renal outcomes. The development of microalbuminuria is now accepted as a marker of systemic endothelial dysfunction and, if it progresses to macroalbuminuria (i.e., >200 mg/d albuminuria), then kidney disease is evident. Collectively, visceral obesity, insulin resistance/hyperinsulinemia, and other components of the cardiometabolic syndrome lead to an increased risk of microalbuminuria and progressive loss of renal function. Hence, aggressive management of risk factors for the metabolic syndrome, nonpharmacologic and pharmacologic, is essential to prevent or delay the progressive loss of renal function and chronic kidney disease.

[Insulin sensitivity and beta cell function in different glucose tolerance status]

The objective of this work was to investigate the insulin sensitivity (SI) and the beta cell function (BCF) in different glucose tolerance statuses in a comparative cross-sectional study. Eighty-four patients with different glucose tolerance statues were classified as normoglicemic-control group (NC) patients without family history of type 2 diabetes (DM2) or hypertension (HTN); normoglicemic-patients with familiar history of DM2 or HTN (FPDM2); patients with glucose intolerance (IGT group) and patients with diagnostic of DM2 <10 years (DM2 group). In each patient was obtained a clinical history and an oral glucose tolerance test (75 g) was performed. Glucose (GOD-PAP) and insulin (RIA) were quantified. Insulin Sensitivity (IS) (Whole Body Insulin Sensitivity Index), Insulin resistance (IR) (HOMA) and BCF (insulinogenic index) were evaluated. The statistical analysis was realized in SPSS v. 10.0. It was found that glucose was similar among NC, FPDM2 and IGT groups. Insulin was higher in the FPDM2 (26.71 +/- 22.25 microU/mL), and IGT (34.10 +/- 34.98 microU/mL) in comparison with NC (22.83 +/- 21.26 microU/mL) (p < 0.01). IS was different among NC and IGT group (0.74 +/- 0.43 to 0.29 +/- 0.18, p < 0.05) and among IGT and DM2 (0.29 +/- 0.18 to 0.86 +/- 0.55, p < 0.001). BCF was different among the DM2 and NC (0.051 +/- 0.05 to 1.28 +/- 1.99 microU.mL/mg.dL, p < 0.05), DM2 and FPDM2 group (0.051 +/- 0.05 to 1.23 +/- 1.51 microU.mL/mg.dL, p < 0.01), DM2 and IGT (0.051 +/- 0.05 to 2.64 +/- 2.22 microU.mL/mg.dL, p < 0.001). SI was inversely related to corporal weight and IMC (r = -0.38, p = 0.001 and r = -0.33, p = 0.004, respectively). BCF was related to age (r = -0.27, p = 0.016), the area under curve of glucose (r = -0.30, p = 0.010) and body weight (r = 0.34, p = 0.002). In conclusion, the decrease of glucose tolerance was associated with the lowering of Insulin Sensitivity (IS). The beta cell function (FCB) was lower in the diabetic patients group in comparison with the TGA and FPDM2 groups. These measurements need to be included in patients with high risk for early identification and changes in life style to protect the normal functioning of beta cell and to prevent the onset of IGT or DM2.

Hyperinsulinemia in cord blood in mothers with type 2 diabetes and gestational diabetes mellitus in New Zealand

OBJECTIVE

In genetically diabetes-prone populations, maternal diabetes during pregnancy increases the risk of their children developing diabetes and obesity (the vicious cycle of type 2 diabetes). Fetal hyperinsulinemia at birth acts as a marker of this risk. We therefore examined whether cord insulin and leptin concentrations are increased in offspring of Maori and Pacific Island mothers with type 2 and gestational diabetes mellitus (GDM) and varying degrees of glycemic control (HbA(1c)).

RESEARCH DESIGNS AND METHODS

Maori and Pacific Island mothers were prospectively recruited at Middlemore Hospital, South Auckland. Cord blood was taken from umbilical vein at birth from singleton babies born after 32 weeks of gestation to 138 mothers with GDM, 39 mothers with type 2 diabetes, and 95 control mothers.

RESULTS

Babies born to mothers with both type 2 diabetes and GDM had higher birth weight and skinfold thickness and markedly higher concentrations of insulin (median [interquartile range] type 2 diabetes 77 pmol/l [42-143], GDM 67 pmol/l [42-235], and control subjects 33 pmol/l [18-62]; P < 0.001) and leptin (type 2 diabetes 39 ng/ml [18-75], GDM 31 ng/ml [17-58], and control subjects 13 ng/ml [8-22]; P < 0.001) in cord blood. Cord insulin concentrations >120 pmol/l were found in 29% of offspring of mothers with GDM and 31% of mothers with type 2 diabetes. Many mothers with GDM had abnormalities of glucose tolerance postpartum (20% type 2 diabetes, 34% impaired glucose tolerance or impaired fasting glucose). Higher cord insulin (57 pmol/l [40-94]) and leptin (26 ng/ml [17-39]) concentrations were found even in offspring of GDM mothers with normal glucose tolerance postpartum.

CONCLUSIONS

Raised cord insulin and leptin concentrations are a common finding in offspring of mothers with type 2 diabetes and GDM in this population.

The PPARG Pro12Ala polymorphism is associated with a decreased risk of developing hyperglycemia over 6 years and combines with the effect of the APM1 G-11391A single nucleotide polymorphism: the Data From an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) study

Although cross-sectional studies have associated the Pro12Ala polymorphism of PPARG with type 2 diabetes, prospective studies offer more opportunities to investigate genetic variants. Associations between PPARG polymorphisms with insulin resistance parameters and with the 6-year incidence of impaired fasting glucose or type 2 diabetes were tested in 3,914 French Caucasians from the DESIR (Data From an Epidemiological Study on the Insulin Resistance Syndrome) cohort. In subjects normoglycemic at baseline (n = 3,498), the 6-year risk of hyperglycemia was lower in PPARG Ala carriers (odds ratio [OR] vs. ProPro = 0.66 [95% CI 0.44-0.99], P = 0.046 adjusted for sex, age, and BMI). Similar results were found with the PPARG C1431T single nucleotide polymorphism (SNP; adjusted OR = 0.65 [0.44-0.96], P = 0.036). Both alleles are in strong linkage disequilibrium (D' = 0.669, P < 0.001). The baseline mean fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were lower in Ala carriers compared with ProPro homozygotes (P = 0.001 for both), with smaller increases in mean insulin and HOMA-IR during follow-up (P = 0.007 and 0.018, respectively). No association with insulin levels or HOMA-IR was found with C1431T. In this cohort, the APM1 G-11391A SNP is associated with the development of hyperglycemia. The combined effects of PPARG Pro12Ala and APM1 G-11391A SNPs showed no interaction on the risk of 6-year hyperglycemia. The PPARG Ala allele showed a relatively high protective effect in developing hyperglycemia and hyperinsulinemia during a 6-year period. Cumulative rather than synergistic effects of PPARG Pro12Ala and APM1 SNPs on diabetes risk are suggested.

The relation between birth weight and insulin resistance in Korean adolescents

Low birth weight is associated with insulin resistance and type 2 diabetes in adults. The fetal programming hypothesis has shown that insulin resistance and its associated metabolic disturbances result from a poor gestational environment, for which low birth weight is a surrogate. An at-home questionnaire survey was performed on 660 middle school students (12-15 years) in Seoul, Korea, and 152 cases were randomly selected based on their birth weight. Subjects were divided into three groups according to birth weight. We recorded their birth weight and measured their current anthropometric data, blood pressure, lipid profile, HOMA-IR, and HOMA-beta, and compared these parameters among the groups. The relation of birth weight to physiological characteristics in adolescence was examined. Systolic blood pressure, lipid profiles, and fasting plasma glucose, HOMA-beta were not significantly different among the groups, but diastolic blood pressure was lower in the third tertile. Insulin, C-peptide, and HOMA-IR were higher in the lower birth weight tertile. After adjustment for confounding factors, birth weight was inversely related to diastolic blood pressure, insulin, C-peptide, and HOMA-IR. We conclude that low birth weight may predict the risk of the insulin resistance and its progression over age, and that adequate gestational nutrition is therefore necessary to prevent low birth weight.

Obesity and extreme obesity, manifest by ages 20-24 years, continuing through 32-41 years in women, should alert physicians to the diagnostic likelihood of polycystic ovary syndrome as a reversible underlying endocrinopathy

OBJECTIVES

Document obesity-extreme obesity in most 20-24, 25-29, and 32-41 years old women with PCOS as a stimulus for physicians to consider the diagnosis of PCOS, an underlying reversible endocrinopathy.

STUDY DESIGN

In matched age groups 20-24, 25-29, and 32-41 years, we compared BMI in 84, 129, and 188 Caucasian women with PCOS versus 956, 815, and 815 women in NHANES I (general population), and 25, 36, and 45 non-pregnant women (community obstetrics practice).

RESULTS

At ages 20-24, 25-29, and 32-41 years, mean+/-S.D. BMIs in women with PCOS (35.3+/-7.7, 36.0+/-9.4, 36.7+/-8.2) were much greater than NHANES I (22.8+/-4.6, 23.3+/-5.0, 24.5+/-5.6; p < .0001), and community (26.1+/-6.8, 26.9+/-6.6, 25.2+/-5.2; p < .0001). Classifying BMI <25 (normal), > or =25-30 (overweight), > or =30-40 (obese), > or =40 (extremely obese), at ages 20-24, 25-29, and 32-41 years: 76, 73, and 78% of PCOS women were obese-extremely obese, versus 7, 11, and 14% of NHANES I, and 20, 28, and 15% of community women. At ages 20-24, 25-29, and 32-41 years, only 10, 12, and 7% PCOS women had BMIs <25, versus 78, 74, and 66% NHANES I, and 48, 47, and 58% of community women.

CONCLUSIONS

Obesity-extreme obesity in women, manifest by ages 20-24 years, continuing through 32-41 years, should alert physicians to the likelihood of PCOS, an underlying, heritable, potentially reversible, insulin resistant endocrinopathy that promotes obesity.

Genetic variance of SGK-1 is associated with blood pressure, blood pressure change over time and strength of the insulin-diastolic blood pressure relationship

BACKGROUND

Insulin stimulation of the serum- and glucocorticoid-regulated kinase 1 (SGK-1) prolongs the half-life of the epithelial sodium channel, a protein which is essential for blood pressure regulation. The aim of this study was to investigate if variation in the SGK-1 gene is associated with increased blood pressure and strength of the insulin-blood pressure relationship.

METHODS

A promoter C/T, an intron 6 C/T and an exon 8 C/T polymorphism in the SGK-1 gene were genotyped in 4830 subjects from the Malmö Diet and Cancer (MDC) material of whom 4001 were free from antihypertensive medication. Of these, 2171 subjects had also been investigated 11.2 +/- 4.4 years earlier in the Malmö Preventive Project (MPP).

RESULTS

In untreated MDC subjects, intron 6 CC genotype carriers had higher diastolic blood pressure than carriers of the T allele (P = 0.02) and exon 8 C allele carriers had higher systolic blood pressure than TT genotype carriers (P = 0.05). Subjects simultaneously carrying the intron 6 CC genotype and the exon 8 CC or CT genotype (SGK-1 risk) had higher systolic blood pressure (P = 0.03) and higher diastolic blood pressure (P = 0.009) than noncarriers. From MPP to MDC, the percent change in blood pressure per year was higher for systolic blood pressure (P = 0.002) and diastolic blood pressure (P = 0.001) in SGK-1 risk carriers than noncarriers. The correlation between fasting plasma insulin concentration and diastolic blood pressure was stronger in SGK-1 risk carriers than in non-carriers (P = 0.04).

CONCLUSION

Our data suggest that SGK-1 risk carriers are at increased risk of hypertension and are more sensitive to the blood pressure elevating effects associated with hyperinsulinemia.

Cross-sectional correlates of fasting hyperinsulinaemia in post-menopausal women of different ethnic origin

AIMS

In a large ethnically diverse nationwide sample of post-menopausal women we explored the relationship between fasting insulin levels, ethnicity, and a wide range of anthropometric, socio-economic, and lifestyle factors.

METHODS

Subjects were post-menopausal women aged 50-79 years without diagnosed diabetes mellitus comprising a subsample (n = 3500) of the Women's Health Initiative (WHI) Clinical Trial and Observational Study. In a cross-sectional survey at baseline, we analysed the association between ethnicity and fasting insulin using analysis of covariance procedures and identified independent correlates of hyperinsulinaemia, defined by the 75th percentile cut point for each ethnic group.

RESULTS

Fasting insulin levels were higher among African-American and Hispanic women than among non-Hispanic White or Asian women. These differences persisted after adjustment for age, educational attainment, total and central body obesity, adult weight change, family history of diabetes, smoking status, alcohol consumption, use of menopausal hormone therapy and physical activity. Higher levels of body mass index, waist-hip ratio, adult weight gain, and lower levels of total and moderate or strenuous recreational activity were independent correlates of fasting hyperinsulinaemia. Habitual walking was also inversely associated with fasting insulin.

CONCLUSIONS

In this cross-sectional analysis, fasting insulin levels were higher among African-American and Hispanic post-menopausal women as compared with non-Hispanic White and Asian women. In addition, obesity, adult weight gain, and low levels of moderate or strenuous physical activity were independently associated with hyperinsulinaemia.

Hyperinsulinemia, insulin resistance, and circulating oxidized low density lipoprotein in women with systemic lupus erythematosus

OBJECTIVE

Women with systemic lupus erythematosus (SLE) have increased risk of coronary heart disease (CHD) that is not fully explained by the classic CHD risk factors. Insulin resistance is an established risk factor for CHD in the general population. We compared insulin secretion and sensitivity in patients with SLE and healthy controls, and assessed the prevalence of the metabolic syndrome in women with SLE and its relation to circulating oxidized low density lipoprotein (ox-LDL).

METHODS

Fasting insulin, glucose, and lipid profiles were measured in nondiabetic women with SLE (>or= 4 revised 1997 criteria) not undergoing antimalarial therapy (n = 44), and in age matched controls recruited from the hospital staff and the local community (n = 45). Using the Homeostatic Model Assessment equations, insulin sensitivity (HOMA-S) and pancreatic beta cell function (HOMA-B) were calculated from fasting insulin and glucose. The metabolic syndrome, defined according to the Adult Treatment Panel (ATP III) criteria, was determined in a consecutive series of 61 women with SLE.

RESULTS

Patients with SLE had significantly higher fasting insulin [median (range) 10 (2.8-38) vs 6.6 (3.1-26) mU/l; p < 0.01], higher pancreatic beta cell function (HOMA-B) [165 (54-1567) vs 111 (28-653); p < 0.01], and lower insulin sensitivity (HOMA-S) [0.46 (0.09-1.9) vs 0.73 (0.16-1.3); p < 0.01]. SLE patients also had significantly higher triglycerides (p < 0.01) and lower high density lipoprotein cholesterol (p < 0.01) than controls. HOMA-S did not correlate with disease activity or steroid therapy, but was associated with components of the insulin resistance syndrome. HOMA-S showed a significant negative correlation with levels of ox-LDL in patients, but not in controls. Eleven (18%) patients had the metabolic syndrome. Again, this was not related to current steroid therapy. SLE patients with the metabolic syndrome had no difference in LDL, but had significantly higher levels of ox-LDL.

CONCLUSION

Nondiabetic patients with SLE have evidence of significant decrease in sensitivity to insulin, and overall this population has a high prevalence of the metabolic syndrome (18%). Insulin resistance in the context of SLE was not strongly related to current or recent steroid therapy; it was, however, associated with higher levels of ox-LDL. Insulin resistance may therefore represent an additional CHD risk factor in patients with SLE.

[Hyperinsulinemia and insulin-resistance in climacteric women with metabolic syndrome]

The purpose of the study was to evaluate the peculiarities of carbohydrate and lipid dysmetabolism in climacteric women with metabolic syndrome (MS). The subjects of this case-control study were 124 women. The main group consisted of 62 women with MS according to A TP III classification; the control group included 62 women without MS. Anthropometric parameters, blood levels of glucose and immunoreactive insulin, and lipid exchange indices were measured. Thirty-three patients in the main group were obese, and 12 had an excessive body weight; in the control group these conditions were found in 6 and 23 patients, respectively. Patients in the main group developed insulin resistance (IR) significantly more often than the controls did (33 and 15 cases, respectively); the frequency of arterial hypertension, differed significantly between the groups, too. High incidence of IR and carbohydrate dysmetabolism in climacteric women suffering from MS is associated with lipid exchange disturbances, the latter being an independent risk factor of coronary heart disease.

Insulin resistance in critically ill patients with acute renal failure

Mortality in critically ill patients with acute renal failure (ARF) remains high. Hyperglycemia associated with insulin resistance has been associated with adverse outcomes in critically ill intensive care unit (ICU) patients but has not been examined specifically in patients with ARF. We used data from a subcohort ( n = 90) of the Program to Improve Care in Acute Renal Disease (PICARD), an observational study of 618 adult ICU patients with ARF in whom nephrology service consultation was obtained. We obtained simultaneous measurements of serum glucose, insulin, insulin-like growth factor (IGF)-I, and IGF-1 binding proteins (IGFBP) in 90 patients. Daily glucose determinations were obtained from a larger fraction of the PICARD cohort ( n = 509). Among the 90 patients with intensive metabolic monitoring, glucose concentrations in survivors were significantly lower than in nonsurvivors throughout the 5-wk period ( P = 0.008, adjusted P = 0.013). In the larger PICARD cohort ( n = 509), hyperglycemia was also significantly associated with in-hospital mortality. Mean insulin concentrations were significantly higher (431 ± 508 vs. 234 ± 189 pmol/l, P = 0.03), mean homeostasis model of insulin resistance levels were significantly higher (24.1 ± 30.0 vs. 11.7 ± 12.5, P = 0.04), and IGFBP-3 concentrations were significantly lower (1,190 ± 498 vs. 1,470 ± 581 μg/l, P = 0.02) among nonsurvivors compared with survivors. Insulin resistance as defined by hyperglycemia in the setting of higher insulin concentrations may be associated with mortality in critically ill patients with ARF. The IGF-IGFBP axis may play an important role in this process.

Polycystic ovary syndrome. Revised diagnostic criteria and long-term health consequences

The diagnostic criteria for polycystic ovary syndrome (PCOS) have recently been revised. The polycystic ovarian morphology has been introduced as part of the criteria and an international consensus has been achieved providing the basis for future research and collaboration. It is now accepted that polycystic ovary syndrome has important long-term health implications, including metabolic disorders and increased risk factors for cardiovascular disease. The overall risk of developing type 2 diabetes among women with PCOS was found to be increased 3-7 times. Women with PCOS have increased levels of cardiovascular risk factors: insulin resistance, obesity, dyslipidaemia, hypertension and markers of abnormal vascular function. However, the level of risk for cardiovascular disease remains uncertain. The limited epidemiological data available to date have shown no increase in cardiovascular events although the incidence of cerebrovascular events was increased. The evidence for an increased risk for endometrial carcinoma among women with PCOS is limited. Long-term epidemiological studies of women with well defined PCOS are needed in order to assess the risk of long-term health consequences, to identify the subgroups among PCOS women who need to be targeted and to determine the timing and nature of measures for intervention and prevention.

Prevalence of obesity, acanthosis nigricans and hyperinsulinemia in an adolescent clinic

A descriptive chart analyses was conducted of 100 consecutive patients at an adolescent medicine clinic at West Virginia University School of Medicine between April and May 2002 to determine the prevalence of overweight and obesity, acanthosis nigricans and hyperinsulinemia. Height, weight, body mass index (BMI), blood pressure, and screening for acanthosis nigricans (AN) were recorded. For patients with AN, fasting lipid, glucose, and insulin levels were also recorded. A total of 37% (37/100) of adolescents were found to be significantly overweight or obese, with BMIs greater than the 85th percentile for gender and age, 28% (28/100) had a BMI greater than the 95th percentile for gender and age, and 17% (17/100) were observed to have AN. In this cohort, 94% (16/17) had a BMI greater than the 95th percentile. Patients with AN were found to have higher mean BMI (39.7 vs. 29.7), systolic (132 vs. 122), and diastolic (73 vs. 65) blood pressures that the patients who were obese and did not have AN. In addition, 16 of the 17 adolescents with AN were found to have elevated fasting insulin levels (mean 33.6). A fasting insulin level was not obtained on a 12-year-old girl with AN already receiving treatment with rosiglitazone (Avandia) for type 2 diabetes mellitus. The prevalence of overweight and obesity in patients at the adolescent clinic is over twice the national average. The prevalence of acanthosis nigricans in this mostly non-minority population is over three times the highest previously reported rate for Caucasians.

Cardiovascular risk factors in youth with implications for aging: the Bogalusa Heart Study

Evidence that cardiovascular (C-V) risk factors are identifiable in childhood and are predictive of future C-V risk is now irrefutable. That levels of C-V risk factors track or persist over time is important, since such phenomenon confers a life-long burden of C-V risk and indicates subtle and progressive changes in the C-V system. C-V risk factors occur often in constellation and central obesity and the attendant insulin resistance/hyperinsulinemia underlie the comorbid conditions of dyslipidemia, hypertension, thrombosis, and inflammation, among others. Autopsy studies and non-invasive subclinical C-V imaging studies in youth clearly link the multiple risk factor burdens to adverse C-V system changes. The application of multiple risk factors profiling in young individuals in conjunction with non-invasive measurements of vascular changes can promote successful aging and encourage preventive cardiology beginning in early life.

Effect of Metabolic Syndrome on Heart Attack and Mortality in Mexican-American Elderly Persons: Findings of 7-Year Follow-Up From the Hispanic Established Population for the Epidemiological Study of the Elderly

PURPOSE

We aim to examine the effect of Metabolic syndrome (MetS) on heart attack and overall mortality in Mexican-American elderly persons over 7-year follow-up.

METHODS

We studied 3050 Mexican Americans aged 65 or older from the Hispanic Established Population for the Epidemiological Study of the Elderly conducted in five Southwestern states of the United States. Participants were categorized into two groups: those with or without MetS. A total of 333 (11%) respondents at baseline had met the criteria of MetS (at least three of five characteristics--hyperinsulinemia or fasting plasma glucose > or =110 mg/dl, abdominal obesity, and hypertension--as defined by the World Health Organization).

RESULTS

Of 333 participants with MetS, the mean age was 71.1 years and 68% were females (compared with 73.2 years and 56% in those without MetS). Eighty percent of participants with MetS rated their health as fair or poor, compared to 55% of those participants without MetS. Fifty-four percent and 65% of patients with MetS had arthritis and at least one impairment in instrumental activities of daily living (IADL), compared to 39% and 55% of those participants without MetS. MetS was significantly associated with increased incidence of heart attack (odds ratio: 2.75, 95% confidence interval: 1.67-4.54) and was a significant predictor for overall mortality (hazard ratio: 1.46, 95% confidence interval: 1.16-1.84) over a 7-year period after adjusting for other demographic and clinical variables.

CONCLUSIONS

Among Mexican-American elderly participants, those with MetS had poorer self-rated health. MetS was significantly associated with increased incidence of heart attack and higher mortality over a 7-year period.

Perinatal Morbidity in Women with Undiagnosed Gestational Diabetes in Northern Thuringia in Germany

INTRODUCTION

Undiagnosed gestational diabetes mellitus (GDM) is associated with severe perinatal complications.

PATIENTS AND METHODS

Out of 970 women, infant and maternal morbidity was assessed in 114 mother-children-pairs with an infant birth weight over the 90th percentile (Voigt et al., 1996). It was the aim of this retrospective study to assess the number of mothers with undiagnosed GDM, who have born a macrosomic child.

RESULTS

The macrosomia rate in newborns was 12 % in this study excluding macrosomic infants of mothers with preexisting diabetes mellitus. Maternal data: Age 28.3 +/- 5.3 years, adipositas (body-mass-index > 30 kg/m) in 42.1 % vs. 30.4 % in the peer group (p < 0.02), increase in weight > 15 kg during pregnancy in 57.9 % of the mothers who have given birth to a macrosomic child vs. 30.9 % in the peer group (p < 0.0001), family history of diabetes mellitus (28.0 % vs. 11.3 % in the peer group, p = 0.006), preeclampsia in 8.8 % vs. 2.7 % in the peer group (p = 0.002), cervical insufficiency in 2.6 % vs. 0.4 % in the peer group (p = 0.02). After delivery HbA1c was elevated in 38.6 % of the women having born macrosomic infant (mean HbA1c: 5.0 % +/- 0.5). Infant data: neonatal jaundice 16.7 % vs. 4.5 % in the peer group, p < 0.0001. There were no statistically significant differences concerning perinatal condition and malformations. Neonatal hypoglycaemia occurred in 9.6 % of the macrosomic infants. Cord blood insulin levels were significantly elevated in comparison to the peer group of mothers without metabolic disorders and having born eutroph infants (8.4 mU/l [3.0 - 100.0] vs. 5.3 mU/l [3.0 - 30.7], p = 0.01). 11.4 % of all macrosomic infants had cord blood insulin levels above the normal range.

CONCLUSION

More than one third of the mothers having born one or more macrosomic infants had an impairment of glucose metabolism immediately after birth. The elevated prevalence of preeclampsia in this group confirms the relationship of hypertension and impaired glucose metabolism during pregnancy. The detection of hyperinsulinaemia, postnatal hypoglycaemia, elevated prevalence of neonatal jaundice with need of further therapy and diabetic fetopathy in macrosomic infants of mothers, whose metabolism was not monitored during pregnancy, pinpoint the need for a diagnostic screening for GDM.

Diabetes and brain aging: epidemiologic evidence

Increasingly, data from epidemiologic studies suggest diabetes is a risk factor in old age for brain aging, including cognitive impairment and dementia. These associations may reflect a direct effect on the brain of hyperglycemia, or the effects of the diabetes-associated comorbidities of hypertension, dyslipidemia, or hyperinsulinemia. Epidemiologic data on diabetes and brain aging are reviewed. A brief overview is also given of the physiologic mechanisms supporting the epidemiologic data.

Significant association of insulin and proinsulin with clustering of cardiovascular risk factors

AIM: To investigate the association between true insulin and proinsulin and clustering of cardiovascular risk factors.

METHODS: Based on the random stratified sampling principles, 1196 Chinese people (533 males and 663 females, aged 35-59 years with an average age of 46.69 years) were recruited. Biotin-avidin based double monoclonal antibody ELISA method was used to detect the true insulin and proinsulin, and a risk factor score was set to evaluate individuals according to the number of risk factors.

RESULTS: The median (quartile range) of true insulin and proinsulin was 4.91 mIu/L (3.01-7.09 mIu/L) and 3.49 pmol/L (2.14-5.68 pmol/L) respectively, and the true insulin level of female subjects was significantly higher than that of male subjects (P = 0.000), but the level of proinsulin displayed no significant difference between males and females (P = 0.566). The results of covariate ANOVA after age and sex were controlled showed that subjects with any of the risk factors had a significantly higher true insulin level (P = 0.002 for hypercholesterolemia, P = 0.021 for high low-density lipoprotein cholesterol, P = 0.003 for low high-density lipoprotein cholesterol, and P = 0.000 for other risk factors) and proinsulin level (P = 0.001 for low high-density lipoprotein cholesterol, and P = 0.000 for other risk factors) than those with no risk factors. Furthermore, subjects with higher risk factor scores had a higher true insulin and proinsulin level than those with lower risk factor scores (P = 0.000). The multiple linear regression models showed that true insulin and proinsulin were significantly related to cardiovascular risk factor scores respectively (P = 0.000).

CONCLUSION: True insulin and proinsulin are significantly associated with the clustering of cardiovascular risk factors.

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.

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.

Hepatitis C and nonalcoholic fatty liver disease

Hepatitis C virus (HCV) and nonalcoholic fatty liver disease (NAFLD) are the two most common causes of chronic liver disease in North America. NAFLD represents a spectrum of liver lesions that occur in individuals who either do not consume any alcohol or only consume alcohol in quantities generally considered not to be harmful to the liver. This spectrum consists of isolated hepatic macrovesicular steatosis at one end and nonalcoholic steatohepatitis (NASH) at the other. Hepatic steatosis is present in approximately 50% of the subjects with HCV. Genotype 3 is independently associated with hepatic steatosis. In those with genotype 1 infection, steatosis is associated with features of the metabolic syndrome. The presence of hepatic steatosis correlates with the stage of hepatic fibrosis in patients with HCV. This has been related to the presence of insulin resistance. Hepatic steatosis also adversely affects the virologic response rates to anti-HCV therapy. In this article, we will review the epidemiology of HCV and NAFLD, their impact on each other, and the course of the liver disease in individuals afflicted with both conditions.

Insulin resistance and endothelial function are improved after folate and vitamin B12 therapy in patients with metabolic syndrome: relationship between homocysteine levels and hyperinsulinemia

OBJECTIVE

The purpose of this study was (a) to study whether a folate and vitamin B12 treatment, aimed at decreasing homocysteine levels, might ameliorate insulin resistance and endothelial dysfunction in patients with metabolic syndrome according to the National Cholesterol Education Program-Adult Treatment Panel-III criteria and (b) to evaluate whether, under these metabolic conditions, there is a relationship between hyperhomocysteinemia and insulin resistance.

DESIGN AND METHODS

A double-blind, parallel, identical placebo-drug, randomized study was performed for 2 months in 50 patients. Patients were randomly allocated to two groups. In group 1, patients were treated with diet plus placebo for 2 months. In group 2, patients were treated with diet plus placebo for 1 month, followed by diet plus folic acid (5 mg/day) plus vitamin B12 (500 microg/day) for another month.

RESULTS

In group 2, folate treatment significantly decreased homocysteine levels by 27.8% (12.2+/-1.2 vs 8.8+/-0.7 micromol/l; P<0.01). A significant decrement was observed for insulin levels (19.9+/-1.7 vs 14.8+/-1.6 microU/ml; P<0.01) accompanied by a 27% reduction in the homeostasis model assessment levels. A positive relationship was found between the decrement of homocysteine and insulin levels (r=0.60; P<0.002). In parallel, endothelial dysfunction significantly improved in the treated group, since post-ischemic maximal hyperemic vasodilation increased by 29.8% and cGMP by 13.6% while asymmetrical dimethylarginine levels decreased by 21.7%. On the contrary, in group 1 patients, treated with placebo, no changes were shown in any of the variables.

CONCLUSIONS

Folate and vitamin B12 treatment improved insulin resistance and endothelial dysfunction, along with decreasing homocysteine levels, in patients with metabolic syndrome, suggesting that folic acid has several beneficial effects on cardiovascular disease risk factors.

Glucose and insulin components of the metabolic syndrome are associated with hyperandrogenism in postmenopausal women: the atherosclerosis risk in communities study

In 1990-1992, the authors investigated the association of total and free testosterone with the metabolic syndrome in postmenopausal US women not taking hormone replacement therapy (n=362) in a prevalent case-control study of carotid atherosclerosis. Free testosterone was estimated by using the free androgen index (FAI) (total testosterone/sex hormone-binding globulin ratio). The metabolic syndrome was defined as the presence of three or more of the following criteria: waist circumference > or =35 inches (88.9 cm), triglycerides > or =150 mg/dl, high density lipoprotein cholesterol <40 mg/dl, blood pressure >130/80 mmHg, fasting insulin > or =100 pmol/liter, or impaired glucose homeostasis (fasting glucose > or =110 mg/dl or diagnosed diabetes mellitus). FAI, but not total testosterone, was strongly associated with the metabolic syndrome. Compared with women in the lowest FAI quartile, those in the highest quartile had a fivefold greater odds of having the metabolic syndrome (odds ratio=5.38, 95% confidence interval: 2.70, 10.7) after adjustment for age, race, and carotid atherosclerosis status. In multivariate analyses, the three-component metabolic syndrome combinations that contained both hyperinsulinemia and hyperglycemia were most strongly associated with increased FAI (absolute increase=0.41-0.54 compared with that for women who did not have these combinations; all p's < 0.001). Higher FAI was associated with the hyperinsulinemia and hyperglycemia components of the metabolic syndrome. The role of androgens in glucose homeostasis in postmenopausal women requires further study.

National Cholesterol Education Program versus World Health Organization metabolic syndrome in relation to all-cause and cardiovascular mortality in the San Antonio Heart Study

BACKGROUND

To assess the utility of clinical definitions of the metabolic syndrome (MetS) to identify individuals with increased cardiovascular risk, we examined the relation between the MetS, using both the National Cholesterol Education Program (NCEP) and the World Health Organization definitions, and all-cause and cardiovascular mortality in San Antonio Heart Study participants enrolled between 1984 and 1988.

METHODS AND RESULTS

Among 2815 participants, 25 to 64 years of age at enrollment, 509 met both criteria, 197 met NCEP criteria only, and 199 met WHO criteria only. Over an average of 12.7 years, 229 deaths occurred (117 from cardiovascular disease). Moreover, in the primary prevention population of 2372 participants (ie, those without diabetes or cardiovascular disease at baseline), 132 deaths occurred (50 from cardiovascular disease). In the primary prevention population, the only significant association adjusted for age, gender, and ethnic group was between NCEP-MetS and cardiovascular mortality (hazard ratio [HR], 2.01; 95% CI, 1.13-3.57). In the general population, all-cause mortality HRs were 1.47 (95% CI, 1.13-1.92) for NCEP-MetS and 1.27 (95% CI, 0.97-1.66) for WHO-MetS. Furthermore, for cardiovascular mortality, there was evidence that gender modified the predictive ability of the MetS. For women and men, respectively, HRs for NCEP-MetS were 4.65 (95% CI, 2.35-9.21) and 1.82 (95% CI, 1.14-2.91), whereas HRs for WHO-MetS were 2.83 (95% CI, 1.55-5.17) and 1.15 (95% CI, 0.72-1.86).

CONCLUSIONS

In summary, although both definitions were predictive in the general population, the simpler NCEP definition tended to be more predictive in lower-risk subjects.

Fasting insulin and incident dementia in an elderly population of Japanese-American men

OBJECTIVE

To evaluate the association of fasting insulin level to incident dementia in a cohort of elderly men.

METHODS

Data are from the Honolulu-Asia Aging Study, a community-based study of Japanese-American men, aged 71 to 91 years in 1991. Serum insulin was measured in 1991 and participants were grouped based on their insulin levels. Dementia was ascertained in 1991, 1994, and 1996 according to international guidelines. The 2,568 men dementia-free in 1991 were reexamined in 1994 and 1996; 244 new cases of dementia were diagnosed. Survival analysis with age as the time scale was used to estimate the risk (hazard ratio [HR] and 95% CI) for incident dementia associated with levels of insulin.

RESULTS

The risk of dementia was increased at the two extremes of the insulin distribution (lower and upper 15th percentiles). Compared to the rest of the cohort subjects in the lowest 15th percentile and highest 15th percentile had an increased risk for dementia (HR = 1.54, CI 1.11 to 2.11 and HR = 1.54, CI 1.05 to 2.26). In men with insulin levels <22.2 mIU/L the risk for dementia decreased with increased levels of insulin (HR = 0.76, CI 0.72 to 0.79 for each increase of one logarithmic unit -2.72 mIU/L of insulin). In men with insulin levels >/=22.2 mIU/L the risk for dementia increased with increasing levels of insulin (HR = 1.64, CI = 1.07 to 2.52 for each 2.72 mIU/L).

CONCLUSIONS

Both low and high levels of insulin are associated with an increased risk of developing dementia.

Clinical, haemodynamic, anthropometric, metabolic and insulin profile of men with high-stage and high-grade clinical prostate cancer

AIMS

Previous studies have shown that non-insulin-dependent diabetes mellitus (NIDDM), hypertension, atherosclerotic disease manifestations, tallness, obesity, dyslipidaemia, hyperuricaemia, hyperinsulinaemia and high alanine aminotransferase (ALAT) levels are risk factors for development of benign prostatic hyperplasia (BPH). This indicates that BPH is a component of the metabolic syndrome. In a subsequent study, we found that there was an association between the BPH growth rate and the development of clinical prostate cancer. These findings generated a hypothesis that clinical prostate cancer also was a component of the metabolic syndrome. In the present study, this hypothesis was tested on 299 patients with recently diagnosed clinical prostate cancer. If this hypothesis is true, patients with clinical prostate cancer of high stage and grade would have a larger prostate gland volume, a faster BPH growth rate and a more pronounced clinical, haemodynamic, anthropometric, metabolic and insulin profile than patients with clinical prostate cancer of low stage and grade have.

METHODS

Two hundred and ninety-nine patients in whom clinical prostate cancer was diagnosed were consecutively included. The prevalence of NIDDM, treated hypertension and atherosclerotic manifestations was provided by the respective patient's medical history. Body length, body weight, waist measurement, hip measurement and blood pressure were determined. Body mass index (BMI) and waist/hip ratio (WHR) were calculated. Blood samples were drawn to determine triglycerides, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, uric acid, ALAT and the fasting plasma insulin level. The prostate gland volume was measured using transrectal ultrasound. The annual BPH growth rate was calculated. The prostate cancer diagnosis was established.

RESULTS

Patients with clinical prostate cancer, prostate-specific antigen (PSA) < 50 ng/ml, stage T3, had a bigger prostate gland volume (p < 0.001), a faster BPH growth rate (p < 0.001), were more obese, as measured by body weight (p = 0.062), BMI (p = 0.003), waist measurement (p = 0.011) and hip measurement (p = 0.051) and showed a higher systolic blood pressure (p < 0.070) than patients with T2 clinical prostate cancer. When patients with clinical prostate cancer, PSA > 50 ng/ml, were included at the comparison, T3 tumour patients showed a higher prevalence of treated hypertension (p = 0.026) than patients with T2 tumours. Patients with clinical prostate cancer, PSA < 50 ng/ml, G3, had a greater prostate gland volume (p = 0.004), a faster BPH growth rate (p = 0.005) and were more obese as determined by waist measurement (p = 0.044) and WHR (p = 0.073). Moreover, subjects with a G3 tumour were more dyslipidaemic, as shown by a higher triglyceride level (p = 0.019) and a lower HDL-cholesterol level (p = 0.005), and were more hyperuricaemic (p = 0.023), showed a higher plasma insulin level (p = 0.019) and a higher ALAT level (p = 0.061) than those with a G1 tumour. When patients with clinical prostate cancer, PSA > 50 ng/ml, were included at the comparison, G3 patients had a greater prostate gland volume (p = 0.002) and a faster BPH growth rate (p = 0.003) than patients with G1 tumours.

CONCLUSIONS

The results of the present study suggest that the prostate gland volume, the BPH growth rate, hypertension, obesity, dyslipidaemia, hyperuricaemia, hyperinsulinaemia and high ALAT levels are risk factors for the development of clinical prostate cancer. Thus, our results support the hypothesis that clinical prostate cancer is a component of the metabolic syndrome. Patients with clinical prostate cancer may have the same metabolic abnormality of a defective insulin-stimulated glucose uptake and secondary hyperinsulinaemia as patients with the metabolic syndrome. Our data also support the hypothesis that hyperinsulinaemia is a promoter of clinical prostate cancer.

Insulin Resistance and Hypertension

The association between insulin resistance and insulinemia and hypertension is controversial. We examined the relation between insulin resistance and hypertension in 564 non-Hispanic whites (NHW), 505 Hispanics (H), and 413 African Americans (AA) who participated in the Insulin Resistance Atherosclerosis Study (IRAS). Insulin sensitivity was measured with a frequently sampled intravenous glucose tolerance test with minimal model analysis. The prevalence of hypertension was 32.5%, 49.4%, and 32.3% in NHW, AA, and H, respectively ( P <0.001). When subjects without diabetes in all ethnic groups were combined, age, male sex, race (AA), body mass index (BMI), and insulin resistance, but not fasting insulin, were significantly associated with hypertension. When each ethnic group was analyzed separately, insulin resistance was significantly associated with hypertension in NHW and H, but not AA. After excluding subjects taking antihypertensive medications, male sex, BMI, fasting glucose, and insulin resistance, but not fasting insulin, were significant determinants of blood pressure. When the 3 ethnic groups were analyzed separately, insulin resistance was significantly associated with blood pressure in H, but not NHW, or AA. Neither insulin resistance nor fasting insulin was significantly associated with hypertension or blood pressure in subjects with diabetes of the 3 ethnic groups after adjusting for age, sex, BMI, and waist. In conclusion, insulin resistance, but not insulinemia, was related to hypertension and blood pressure in subjects without diabetes, but ethnic differences in these relations appear to exist. Neither insulin resistance nor insulinemia was related to hypertension or blood pressure in patients with type 2 diabetes in the 3 ethnic groups.

Glucocorticoids and insulin sensitivity in rheumatoid arthritis

OBJECTIVE

To evaluate the effects of glucocorticoids on cardiovascular (CV) risk in rheumatoid arthritis (RA).

METHODS

We recorded demographic, clinical, disease outcome, and treatment variables in 92 consecutive RA patients who were not taking lipid-lowering or antidiabetic medications. Fasting blood tests were taken for determination of lipids, ultra sensitive C-reactive protein (CRP), rheumatoid factor, insulin, and glucose. Insulin sensitivity was determined using the Quantitative Insulin Sensitivity Check Index (QUICKI).

RESULTS

Seventy-four (80%) patients were women, 80 Caucasian, 9 Asian, 2 of mixed ancestry and 1 Black. Their mean (95% confidence interval, CI) age, disease duration, and followup duration at our clinic were 56 (54-58), 11 (9-13) and 6 (5-6) years, respectively. Thirty-seven (40%) patients had received oral prednisone [cumulative dose 4.8 (2.0-8.5) g; duration one month to 20 years], and all patients had received pulsed (intraarticular, intramuscular, and/or intravenous) methylprednisolone [cumulative dose 2.0 (1.6-2.6) g]. Glucocorticoids were not associated with obesity, hypertension, or dyslipidemia. Having taken prednisone and high yearly frequencies of pulsed glucocorticoid administrations were associated with decreased insulin sensitivity (p < 0.05). After controlling for body mass index, ever having taken prednisone and high doses of pulsed glucocorticoids were independently associated with decreased insulin sensitivity (p < 0.05).

CONCLUSION

Previous exposure to oral prednisone and high doses of pulsed glucocorticoids were associated with decreased insulin sensitivity in RA. Since decreased insulin sensitivity is an independent risk factor for CV disease, glucocorticoids may contribute to the excess CV event rates in RA.

Manifestations of Metabolic Syndrome After Hypertensive Pregnancy

Small follow-up studies of hospital-based series indicate women with preeclampsia have an increased risk of insulin resistance postpartum. However, long-term data are lacking among women with gestational hypertension without proteinuria. Using a general population-based sample of 5889 women from Northern Finland followed longitudinally since birth in 1966, we examined these associations and the influence of the subject’s own birth weight and gestational age on this relationship. At age 31, blood pressure was measured and blood samples collected from 2678 women, of which 1463 women had had at least 1 singleton pregnancy. Of these, 45 had been hospitalized because of gestational hypertension and 49 because of preeclampsia. Women who had had either gestational hypertension or preeclampsia during their first pregnancy (average age 25 years) had increased blood pressure at 31 years compared with women with previous normotensive pregnancy, even after adjustment for body mass index ( P <0.001 in gestational hypertension, P =0.023 in preeclampsia group). When compared with the whole female population, women with previous gestational hypertension at same age still had higher blood pressure, while this difference was weaker for women with previous preeclampsia. Women with gestational hypertension and preeclampsia also had higher waist circumference, waist/hip ratio, and body mass index, as well as increased serum insulin levels and lower glucose/insulin ratio than women with previous normotensive pregnancy. The associations remained after adjustment for participant’s own birth weight or gestational age. Women born before gestational week 37 had a 2-fold risk for gestational hypertension in their first pregnancy (RR: 2.53; 95% CI: 1.0, 6.2).

Carotid Arterial Remodeling

Background and Purpose— Deteriorating glucose tolerance is associated with an increased cardiovascular disease (CVD) risk. The underlying mechanisms remain unclear. Arterial remodeling is the change in structural properties through time in response to atherogenic and/or hemodynamic alterations and aims to maintain circumferential wall stress constant (σ C ). Arterial remodeling has not been studied in relation to glucose tolerance.

Methods— The study population consisted of 278 people with normal glucose metabolism, 168 with impaired glucose metabolism, and 301 with type 2 diabetes (DM-2); their mean age was 67.8 years. We assessed carotid intima-media thickness (IMT), interadventitial diameter (IAD), lumen diameter (LD), and σ C .

Results— After adjustment for age, sex, height, body mass index, and prior CVD, DM-2 was associated with increased IAD, IMT, and σ C but not LD (regression coefficients: 0.24 mm; 95% confidence interval [CI], 0.07 to 0.41; 0.050 mm; 95% CI, 0.024 to 0.077; 5.00 kPa; 95% CI, 0.92 to 9.08; and 0.13 mm; 95% CI, −0.03 to 0.29, respectively). After additional adjustment for pulse pressure, the association between DM-2 and IAD disappeared, whereas the association with IMT remained. After adjustment, impaired glucose metabolism was not significantly associated with LD (0.12 mm; 95% CI, −0.06 to 0.33), σ C (0.25 kPa; 95% CI, −4.49 to 4.98), IAD (0.08 mm; 95% CI, −0.11 to 0.27), or IMT (0.029 mm; 95% CI, −0.002 to 0.060). However, the IMT regression coefficient was half that of DM-2.

Conclusions— DM-2 is associated with preserved LD at increased IMT, which, however, does not normalize the increased σ C . In contrast, impaired glucose metabolism is not associated with changes in LD or IAD, whereas IMT is moderately increased but σ C remains constant. Carotid remodeling in DM-2 thus appears maladaptive, which may explain the increased CVD risk, especially stroke, in DM-2.

Prevalence of hyperinsulinemia and clinical correlates in overweight children referred for lifestyle intervention

Although not well documented in the literature, there is growing evidence that overweight children may develop hyperinsulinemia. Children (n=171) with a body mass index greater than the 85th percentile for age using the Centers for Disease Control and Prevention growth charts for children were recruited through primary care physician offices for a lifestyle change intervention. Laboratory measurements were obtained. About 30% of these children were identified as hyperinsulinemic, using an insulin-to-glucose ratio of > or =33% or a serum insulin > or =25 microU/mL. When compared with non-hyperinsulinemic children, there were significant differences in cardiovascular risk factors. Dietetics professionals providing medical nutrition therapy to overweight children need to be aware of dietary and physical activity recommendations for individuals with marked hyperinsulinemia.

High insulin levels and increased low-density lipoprotein oxidizability in pediatric patients with systemic lupus erythematosus

OBJECTIVE

To examine low-density lipoprotein (LDL) size, LDL susceptibility to oxidation, and plasma insulin levels in children with systemic lupus erythematosus (SLE).

METHODS

Fifty-nine SLE patients and 59 healthy, age-matched control subjects were studied. LDL size was determined by gradient gel electrophoresis. LDL oxidizability was assessed by lag time for conjugated diene formation during copper incubation. Plasma levels of fasting insulin, glucose, lipids, lipoproteins, apolipoproteins B and A-I, and fatty acids were also measured.

RESULTS

Compared with control subjects, SLE patients showed significantly higher plasma insulin levels and increased susceptibility of LDLs to oxidation. Patients with active disease were more likely than patients with inactive disease or control subjects to have the following lipid characteristics: small, dense LDL subclass, elevated total cholesterol levels, elevated LDL cholesterol levels, elevated triglyceride levels, and low levels of high-density lipoprotein cholesterol (HDL-C). Statistically significant direct correlations were observed between disease activity and triglyceride levels and between disease activity and lag time, whereas significant inverse correlations were found between disease activity and HDL-C levels and between disease activity and LDL size. Prednisone dosage explained only 15.6% of the variance in insulin levels.

CONCLUSION

SLE patients have higher plasma insulin levels and increased LDL oxidizability compared with healthy control subjects. These abnormalities may contribute to the accelerated atherosclerosis observed in patients with SLE.

Novel insights into the endocrine-metabolic and reproductive consequences of prenatal growth restraint in girls. Girls-born-small become women-born-small

Emerging evidence indicates that prenatal growth relates to common disease in adulthood. Here, we review and embed a selection of advances within this field of research. Focus is on endocrine-metabolic and reproductive facets in girls and young women, who experienced a degree of prenatal growth restraint. Such early restraint has now been linked to variable constellations including the following: hyperinsulinemia; dyslipidemia; central adiposity; exaggerated adrenarche and precocious pubarche; early and rapidly progressive puberty; ovarian hyperandrogenism; elevated serum FSH and/or LH; small uterine and/or ovarian size; and oligo- or an-ovulation. Hyperinsulinemic insulin resistance is thought to be a prime pathogenetic factor. Accordingly, insulin sensitization is among the first therapeutic strategies explored, so far, with promising results.

The roles of insulin resistance, hyperinsulinemia, and thiazolidinediones in cardiovascular disease

Although it is difficult to distinguish between the relative effects of insulin resistance and hyperinsulinemia, insulin resistance is clearly associated with significantly increased cardiovascular and cerebrovascular risk. This effect is consistent across the spectrum of worsening glycemic control, from the onset of impaired glucose tolerance to the development of clinical diabetes. It is more difficult to discriminate between the roles of elevated circulating insulin and proinsulin levels; the association between insulin levels and cardiovascular risk is weak. The thiazolidinediones (TZDs) significantly improve insulin sensitivity and exert numerous effects on the vascular bed, including improved endothelial function, decreased vascular inflammation, decreased plasma free fatty acid levels, improved dyslipidemic profiles, and inhibition of vascular smooth muscle proliferation. These findings provide increasing evidence to suggest that the TZDs may have a beneficial effect on atherosclerosis and may reduce the incidence and severity of adverse cardiovascular outcomes. These effects remain to be substantiated by the results of large outcomes studies to evaluate the impact of glycemic control and reversal of insulin resistance on cardiovascular events.

Comparison of the Associations of Apolipoprotein B and Low-Density Lipoprotein Cholesterol With Other Cardiovascular Risk Factors in the Insulin Resistance Atherosclerosis Study (IRAS)

Background— Risk factors for vascular disease include obesity, dyslipidemia, hypertension, dysglycemia, insulin resistance, inflammation, thrombosis, and subclinical atherosclerosis. This study compares the associations of apolipoprotein B (apoB) and LDL cholesterol (LDLC) with a wide array of measures of these risk factors.

Methods and Results— In 1522 individuals in the Insulin Resistance Atherosclerosis Study, anthropometric measures and measures of lipids, apoB, C-reactive protein, fibrinogen, plasminogen activator inhibitor-1 (PAI-1), fasting and postglucose load glucose and insulin concentrations, and carotid artery intima-media thickness (IMT) were taken and insulin sensitivity was determined by frequently sampled intravenous glucose tolerance test. There were significant differences in measures of abdominal obesity, dyslipidemia, hyperinsulinemia, and thrombosis between subjects with elevated apoB but normal LDLC versus those with elevated LDLC but normal apoB. In each statistically significant comparison, the elevated-apoB group had higher associated risk than the elevated-LDLC group. Moreover, apoB is highly significantly ( P <0.0001) correlated with each measure in the direction of higher risk, whereas LDLC was significantly correlated ( P <0.05) only with blood pressure, triglyceride, fibrinogen, and C-reactive protein. After further adjustment for LDLC, apoB correlations remained significant, whereas several LDLC correlations adjusted for apoB became significant in the direction of lower risk.

Conclusions— Elevated apoB is more strongly associated than LDLC with other risk factors, including measures in the National Cholesterol Education Program guidelines for lipid treatment and other more recently established risk factors. This may provide new insight into why apoB is a better predictor of vascular risk than LDLC.

Long-Term (2???4 Year) Weight Reduction With Metformin Plus Carbohydrate-Modified Diet in Euglycemic, Hyperinsulinemic, Midlife Women (Syndrome W)

Long-term weight reduction remains the ultimate objective and challenge of obesity management. Few long-term dietary or pharmacointervention studies have been conducted and there is a critical need for long-range treatment strategies that are effective, safe, and acceptable. The authors conducted a retrospective cohort analysis of 21 euglycemic, hyperinsulinemic women with progressive, refractory, midlife weight gain (Syndrome W) who had previously lost weight (> or =10% reduction from baseline) with a comprehensive 1-year treatment program that included metformin and a hypocaloric, carbohydrate-modified (low-glycemic index) diet, as well as, other lifestyle modifications. The goal of the analysis was to determine long-term efficacy of the composite intervention using NHLBI criteria for weight stabilization, weight regain < or =3 kg (6.6 lb) in 2 years. Of a total of 26 consecutive women with Syndrome W who achieved goal weight during a 3-year period (1998-2001), 21 women (mean [standard error] age, 55.2 [2.4] years; mean body mass index, 34.2 [1.3] kg/m(2)) continued metformin and returned for annual follow-up visits. Weight maintenance was observed at the final (2-4 year) follow-up visit in 19/21 (90.5%) of women. Mean final follow-up weight (77.5 [2.8] kg) correlated highly with mean weight at 1-year protocol completion (77.2 [2.7] kg), (correlation coefficients r(xy) and sigma(xy) = 0.96, P = 0.000), demonstrating long-term weight reduction in the surveillance phase. Significant and robust decrements in fasting insulin (-28.4% [8.1%] to -43.4% [3.7%]) were observed at all follow-up visits (P < or = 0.002). This preliminary case series suggests that metformin may be an effective long-term adjunct to dietary and other interventions in the treatment of obesity in hyperinsulinemic patients. A randomized clinical trial of the dual regimen should be considered in nondiabetic women with midlife weight gain and hyperinsulinemia (Syndrome W) and, quite possibly, in additional euglycemic overweight and obese subjects with documented hyperinsulinemia and other portentous features of the Metabolic Syndrome.