Biomedical subjects

M Muggeo

Publications and source records attributed to M Muggeo.

At least 55 records · Page 3Linked to original sources

PubMed1999

Spironolactone, but not flutamide, administration prevents bone loss in hyperandrogenic women treated with gonadotropin-releasing hormone agonist.

GnRH agonists (GnRHa) have recently been proposed for the treatment of hirsutism in women with the polycystic ovary syndrome (PCOS). As most of these subjects have increased androgen secretion from both ovaries and adrenal glands, the association of GnRHa with antiandrogen drugs might enhance the clinical response to treatment. On the other hand, this association might also potentiate the adverse effects of GnRHa on bone metabolism, generating a potentially harmful situation at the skeletal level. In this study we investigated in 41 PCOS patients the skeletal effects of a 6-month course of GnRHa (tryptorelin, 3.75 mg, i.m., monthly), either alone (n = 12) or associated with the antiandrogen drugs spironolactone (100 mg, orally, once daily; n = 14) or flutamide (250 mg, once daily; n = 15). In all subjects bone mineral density was measured before and after treatment by dual energy x-ray absorptiometry at the lumbar spine (L2-L4) and at the femoral neck and Ward's triangle. In addition, at baseline and after 6 months of therapy, bone metabolism markers (serum and urinary calcium, serum phosphorus and alkaline phosphatase, plasma osteocalcin, and urinary hydroxyproline) and endocrine parameters (serum gonadotropins, estradiol, and free testosterone) were assayed. Women given either GnRHa alone or associated with spironolactone or flutamide were similar for age and body mass index. At baseline, the 3 groups of PCOS women were also similar for endocrine and bone parameters. After 6 months, all treatments determined similar striking suppressions of serum gonadotropins and sex steroids. Concurrently, bone mineral density was significantly reduced at all examined sites in subjects receiving either GnRHa alone or GnRHa plus flutamide. Conversely, women given GnRHa plus spironolactone did not show any change in skeletal mass from baseline values (P < 0.05-0.01 among groups). Biochemical parameters of bone metabolism were consistent with densitometric assessments. In conclusion, after a 6-month course of therapy, bone mineral density is reduced in PCOS women given either GnRHa alone or GnRHa plus flutamide, but not in those receiving GnRHa plus spironolactone. The mechanisms of the bone-sparing effect of spironolactone remain to be determined. Nevertheless, this drug could represent a useful tool to prevent skeletal loss in women given GnRHa as well as in other hypoestrogenic conditions, in particular when estrogens are not recommended.

Adult↗

PubMed1999

Effect of chronic treatment with lacidipine or lisinopril on intracellular partitioning of glucose metabolism in type 2 diabetes mellitus.

Antihypertensive treatment is frequently needed in type 2 diabetes. In this study we measured the rates of total, oxidative, and nonoxidative glucose disposal, glycogen synthesis, glycolysis, endogenous glucose production, and lipid oxidation using a 4-h euglycemic (approximately 5 mmol/L) hyperinsulinemic (approximately 300 pmol/L) clamp in combination with a dual glucose tracer infusion ([3-(3)H]- and [U-14C] D-glucose) and indirect calorimetry in 40 nonobese subjects with type 2 diabetes. Subjects were studied twice: after a 4-week run-in period and after a 16-week period of double blind, randomized treatment with 4-6 mg/day lacidipine, a calcium channel blocker (n = 19), or 10-20 mg/day lisinopril, an angiotensin-converting enzyme inhibitor (n = 21). Antihypertensive treatment resulted in a significant increase in total glucose disposal during insulin clamp as well as in basal and insulin-stimulated nonoxidative glucose disposal rates. On the contrary, oxidative glucose disposal was significantly decreased by antihypertensive treatment, mainly in the basal state. The changes in glucose disposal rates were not significantly different in subjects treated with lacidipine and in those treated with lisinopril. The suppression of endogenous glucose production during insulin clamp was significantly greater after lacidipine than after lisinopril. These results suggest that treatment of subjects with type 2 diabetes with either lacidipine or lisinopril has no adverse effect on glucose metabolism. Conversely, both drugs seem to improve insulin sensitivity.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1999

Chronic cigarette smoking is associated with increased plasma circulating intercellular adhesion molecule 1 levels in young type 1 diabetic patients.

OBJECTIVE: The purposes of this study were to compare plasma concentrations of circulating intercellular adhesion molecule 1 (cICAM-1), a marker of endothelial dysfunction, in nondiabetic subjects and type 1 diabetic patients and to evaluate whether chronic cigarette smoking had a deleterious effect on plasma cICAM-1 levels in type 1 diabetic patients. RESEARCH DESIGN AND METHODS: Plasma cICAM-1 concentrations were measured in 54 young type 1 diabetic patients without clinical macroangiopathy and in 20 healthy control subjects who were matched for age, sex, BMI, and smoking habit. RESULTS: Type 1 diabetic patients had significantly higher plasma levels of cICAM-1 than control subjects (280.4 +/- 59 vs. 224 +/- 53.6 ng/ml, respectively) (P < 0.001). After stratification by smoking status, diabetic smokers had values for age, sex, BMI, lipids, blood pressure, glycemic control, diabetes duration, and chronic complications of diabetes that were super-imposable on their nonsmoking counterparts. Nevertheless, plasma cICAM-1 levels were markedly elevated in type 1 diabetic smokers (321.4 +/- 64.2 vs. 257.3 +/- 41.5 ng/ml, respectively) (P < 0.001) in a dose-dependent fashion (P < 0.001 by analysis of variance when subjects were categorized by number of cigarettes smoked per day). CONCLUSIONS: Chronic cigarette smoking has a deleterious effect on plasma cICAM-1 levels in young type 1 diabetic patients, which further supports the clinical importance of discouraging the initiation of smoking and promoting its cessation in people with type 1 diabetes.

Adult↗

PubMed1999

Cause-specific mortality in type 2 diabetes. The Verona Diabetes Study.

OBJECTIVE: This population-based study, carried out in the framework of the Verona Diabetes Study, investigated mortality from specific causes in known type 2 diabetic patients. RESEARCH DESIGN AND METHODS: A cohort of 7,148 known type 2 diabetic patients (3,366 men and 3,782 women) was identified on 31 December 1986 and followed up for 5 years (1987-1991). Underlying causes of death were obtained from death certificates and were coded according to the International Classification of Diseases, Ninth Revision. Cause-specific death rates of diabetic subjects were compared with those of the inhabitants of Verona. By 31 December 1991, 1,550 diabetic subjects (744 men and 806 women) had died. RESULTS: The standardized mortality ratio (SMR) for all causes of death was 1.42 (95% CI 1.35-1.50). The highest SMRs were for the following specific causes: diabetes (SMR 4.47 [3.91-5.10]), gastrointestinal diseases (1.83 [1.50-2.21])--particularly liver cirrhosis (2.52 [1.96-3.20])--and cardiovascular diseases (1.34 [1.23-1.44]), particularly cerebrovascular (1.48 [1.25-1.73]) and ischemic heart diseases (1.41 [1.24-1.62]). A significantly higher than expected risk of mortality for cardiovascular causes was already present in the first 5 years after diagnosis and decreased with age. Type 2 diabetic patients treated with insulin had a higher risk of dying than those treated orally or by diet. CONCLUSIONS: The highest SMRs in the diabetic cohort were for diabetes and liver cirrhosis. The mortality risk for cardiovascular diseases, although significantly higher than expected, was much lower in Italian type 2 diabetic patients than that reported for American patients. The evidence of an early effect on mortality suggests that prevention, early diagnosis, and treatment should be improved.

Age Factors↗

PubMed1999

Plasma glucose within the normal range is not associated with carotid atherosclerosis: prospective results in subjects with normal glucose tolerance from the Bruneck Study.

OBJECTIVE: There is substantial evidence that glucose intolerance is associated with an increased risk of cardiovascular disease. However, it is not well established whether plasma glucose is independently related to atherosclerosis when glucose tolerance is normal and, if so, to which stage of the complex atherosclerotic process. RESEARCH DESIGN AND METHODS: We prospectively examined the status of carotid arteries in 625 subjects aged 40-79 years who were randomly selected from the general population and had normal glucose tolerance (according to World Health Organization criteria) both at baseline and at 5 years of follow-up. All subjects had high-resolution echo-duplex evaluation of the common and internal carotid arteries (eight regions of interest on both sides) in 1990 and 1995 to detect the change in carotid status over time. The occurrence of new plaques in previously normal segments was termed "incident nonstenotic" or "early atherosclerosis," and the occurrence of stenosis in >40% of previously normal segments was termed "incident stenotic" or "advanced atherosclerosis." In addition, we evaluated the changes in the atherosclerosis score (the sum of all plaques) during the follow-up, and we measured intimal-medial thickening (IMT) in the common carotid artery in 1995. In all subjects, several candidate risk factors were assessed: sex, age, BMI, waist-to-hip ratio, glucose, HbA1c, insulin, urate, lipids, apolipoproteins A1 and B, blood pressure, lipoprotein(a), fibrinogen, antithrombin III, factor V Leiden mutation, ferritin, leukocyte count, smoking, alcohol intake, physical activity, and socioeconomic status. Fasting plasma glucose (FPG), plasma glucose 2 hr after the glucose load (2-h PG), and HbA1c concentrations in 1990 and 1995 were averaged in each subject to obtain an estimate of long-term glucose exposure of the arterial wall. RESULTS: Linear or logistical regression analyses indicated that neither baseline glucose and HbA1c levels nor mean FPG, mean 2-h PG, or mean HbA1c in 1990 and 1995 were independently related to IMT, a 5-year change in the atherosclerotic score, incident nonstenotic (early) atherosclerosis, or incident stenotic (advanced) atherosclerosis. Likewise, subjects with FPG levels above the median and subjects in the new category of "impaired fasting glucose" did not have an increased occurrence or progression of atherosclerosis. All results were consistent before and after adjustment for other vascular risk factors and possible confounders. CONCLUSIONS: These results suggest that plasma glucose levels within the normal range (<7.8 mg/dl both at FPG and 2-h PG) are not independently related to any stage of atherosclerosis.

Adult↗

PubMed1999

ACE inhibitors improve endothelial function in type 1 diabetic patients with normal arterial pressure and microalbuminuria.

OBJECTIVE: The purpose of this study was to test whether a short-course treatment with ACE inhibitors may restore endothelium-dependent and/or -independent vasodilation in the femoral artery of microalbuminuric patients with type 1 diabetes and normal arterial pressure. RESEARCH DESIGN AND METHODS: We studied nine normotensive microalbuminuric type 1 diabetic patients and two groups of control subjects matched for femoral artery diameter to type 1 diabetic patients after placebo (control group A, n = 17) and ACE inhibitor (control group B, n = 18) treatment, respectively. The patients were enrolled in a double-blind cross-over study with a 1-week trial of either placebo, captopril (25 mg t.i.d.), or enalapril (10 mg/day) in randomized order to ascertain whether short-term ACE inhibition obtained with (captopril) or without (enalapril) a sulfhydryl donor molecule ameliorates vessel wall function. Endothelium-mediated flow-dependent vasodilation and endothelium-independent vasodilation were evaluated in the right common femoral artery by echo Doppler. RESULTS: Both captopril and enalapril normalized (control group B 22.9+/-3.2% per 8 min) endothelium-dependent response (19.6+/-7.5 and 18.0+/-5.3 vs. -10.4+/-4.1% per 8 min, P < 0.01, for both captopril and enalapril versus placebo, respectively) in the type 1 diabetic patients. Captopril (28.4+/-3.5 vs. 17.1+/-3.5% per 5 min during placebo, P < 0.05) but not enalapril (20.1+/-3.0 vs. 31.7+/-2.8% per 5 min, P < 0.05 for enalapril versus control group B, and NS for captopril vs. control group B) ameliorated endothelium-independent vasodilation in type 1 diabetic patients. CONCLUSIONS: ACE inhibition improves endothelium-dependent vasodilation in the femoral artery of normotensive microalbuminuric type 1 diabetic patients. Captopril also ameliorates endothelium-independent vasodilation, possibly through its sulfhydryl donor properties. These results may be of pathophysiological relevance to prevent cardiovascular complications in these patients.

Adult↗

PubMed1998

Accelerated complications in Type 2 diabetes mellitus: the need for greater awareness and earlier detection.

Persistent hyperglycaemia is the underlying pathogenic factor responsible for chronic diabetic complications in Type 1 and Type 2 diabetes mellitus. In Type 1 diabetes, diagnosis is made soon after the onset of hyperglycaemia and several years are required for the resultant complications to appear clinically. The onset of Type 2 diabetes is insidious and is usually recognized only 5-12 years after hyperglycaemia develops. During this period of undiagnosed diabetes, hyperglycaemia, in combination with lifestyle factors (physical inactivity, alcohol use, smoking), and other metabolic (dyslipidaemia, obesity, insulin resistance) and haemodynamic (hypertension) abnormalities frequently associated with Type 2 diabetes, promote the initiation and progression of micro- and macrovascular complications. Furthermore, when blood glucose levels are increased only slightly and no symptoms are apparent, the physician may be reluctant to diagnose Type 2 diabetes or start treatment. This delay in diagnosing the disease results in a high prevalence of chronic complications at the time of actual diagnosis. Indeed, when Type 2 diabetes is diagnosed, cardiovascular disease and neuropathy are found in approximately 10% of cases, and retinopathy and nephropathy in 15-20%. All healthcare providers should be aware of this phenomenon, which may be termed 'accelerated complications', and should plan thorough screening programmes for these conditions at diagnosis. All reversible risk factors associated with diabetes should be identified and treated. When acute metabolic derangements and infections are not the main causes of morbidity and mortality in diabetes, the costs of diabetes care are related mainly to chronic complications of the disease. Therefore, because of the high frequency of Type 2 diabetes, the most efficient method of reducing costs is to increase awareness and secure earlier detection that leads to fast and aggressive treatment of the accelerated chronic complications often seen in Type 2 diabetes.

Amputation, Surgical↗

PubMed1998

Insulin induces tyrosine dephosphorylation of a 92 kDA protein in suspended monocytes.

Monocytes bear insulin receptors similar to those expressed in other tissues, but insulin action in these cells remains unclear. There is evidence that adhesion, by generating a complex array of irreversible transformations, may modify the response of cells to other stimuli, such as hormones. The present study aimed to characterise the pattern of insulin induced tyrosine phosphorylation of monocytes in suspension. Monocytes in suspension were obtained by sequential gradient centrifugation and the tyrosine phosphoproteins were analyzed by immunoblot with antiphosphotyrosine antibodies. The major result of the study is that in suspended monocytes insulin induced a dose and time dependent dephosphorylation of a protein with a molecular mass of about 92 kDa without stimulating the tyrosine phosphorylation of the Insulin Receptor Substrat-1 (IRS-1). In conclusion, we showed that in monocytes in suspension insulin seems to activate a tyrosine phosphatase, which, in turn, dephosphorylates a protein with an apparent molecular weight of 92 kDa.

Humans↗

PubMed1998

Prevalence of insulin resistance in metabolic disorders: the Bruneck Study.

The prevalence of insulin resistance in the most common metabolic disorders is still an undefined issue. We assessed the prevalence rates of insulin resistance in subjects with impaired glucose tolerance (IGT), NIDDM, dyslipidemia, hyperuricemia, and hypertension as identified within the frame of the Bruneck Study. The study comprised an age- and sex-stratified random sample of the general population (n = 888; aged 40-79 years). Insulin resistance was estimated by homeostasis model assessment (HOMA(IR)), preliminarily validated against a euglycemic-hyperinsulinemic clamp in 85 subjects. The lower limit of the top quintile of HOMA(IR) distribution (i.e., 2.77) in nonobese subjects with no metabolic disorders (n = 225) was chosen as the threshold for insulin resistance. The prevalence of insulin resistance was 65.9% in IGT subjects, 83.9% in NIDDM subjects, 53.5% in hypercholesterolemia subjects, 84.2% in hypertriglyceridemia subjects, 88.1% in subjects with low HDL cholesterol, 62.8% in hyperuricemia subjects, and 58.0% in hypertension subjects. The prevalence of insulin resistance in subjects with the combination of glucose intolerance (IGT or NIDDM), dyslipidemia (hypercholesterolemia and/or hypertriglyceridemia and/or low HDL cholesterol), hyperuricemia, and hypertension (n = 21) was 95.2%. In isolated hypercholesterolemia, hypertension, or hyperuricemia, prevalence rates of insulin resistance were not higher than that in nonobese normal subjects. An appreciable number of subjects (n = 85, 9.6% of the whole population) was insulin resistant but free of IGT, NIDDM, dyslipidemia, hyperuricemia, and hypertension. These results from a population-based study documented that 1) in hypertriglyceridemia and a low HDL cholesterol state, insulin resistance is as common as in NIDDM, whereas it is less frequent in hypercholesterolemia, hyperuricemia, and hypertension; 2) the vast majority of subjects with multiple metabolic disorders are insulin resistant; 3) in isolated hypercholesterolemia, hyperuricemia, or hypertension, insulin resistance is not more frequent than can be expected by chance alone; and 4) in the general population, insulin resistance can be found even in the absence of any major metabolic disorders.

Adult↗

PubMed1998

U-shaped and J-shaped relationships between serum insulin and coronary heart disease in the general population. The Bruneck Study.

OBJECTIVE: To evaluate the relationship existing between serum insulin and coronary heart disease (CHD) in the general population. RESEARCH DESIGN AND METHODS: In a cross-sectional survey on atherosclerosis and its risk factors, 500 men and 500 women aged 40-79 years were randomly selected from the population of Bruneck, Italy. Clinical, biochemical, and behavioral risk factors of atherosclerosis were assessed in the 936 subjects who participated in the study. Serum insulin was measured at fasting (n = 888) and 2 h (n = 811, known diabetic subjects were excluded) after an oral glucose load. CHD was ascertained by an abnormal electrocardiogram and/or a history of angina or myocardial infarction. RESULTS: Subjects were stratified according to serum insulin quintiles at fasting or 2 h after glucose loading. After adjustment for sex, age, BMI, smoking, physical activity, alcohol intake, and socioeconomic status (analysis of covariance), cardiovascular risk factors clustered in subjects of the top insulin quintile. Multiple logistic regression analysis, including sex and age in model 1, sex, age, BMI, glucose tolerance, socioeconomic status, and behavioral variables in model 2, or this set of variables together with triglycerides and apoproteins A1 and B, fibrinogen, and blood pressure status in model 3, revealed a significant association between high serum insulin and CHD when median insulin quintile was used as the reference class. Moreover, low serum insulin levels, such as those found in subjects of the lowest quintile, were independently related to CHD. These results were found either before (model 1) or after (models 2 and 3) adjusting for several covariates. Consistent results were found in men and women, as well as in younger and older subjects. CONCLUSIONS: Results of the present study suggest that both hyperinsulinemia and "hypoinsulinemia" are independent indicators of CHD. Furthermore, it is proposed that the relationship between CHD and fasting insulin is U-shaped, whereas that between CHD and postglucose insulin may be J-shaped.

Adult↗

PubMed1997

Long-term instability of fasting plasma glucose, a novel predictor of cardiovascular mortality in elderly patients with non-insulin-dependent diabetes mellitus: the Verona Diabetes Study.

BACKGROUND: We recently reported that long-term fasting plasma glucose (FPG) instability predicts all-cause mortality in elderly patients with non-insulin-dependent diabetes mellitus (NIDDM). The aim of the present study was to evaluate whether glucose instability, as represented by the coefficient of variation of FPG concentrations (CV-FPG) measured during a 3-year period, can predict specific causes of death in the subsequent 5 years. METHODS AND RESULTS: Five hundred sixty-six elderly patients with NIDDM were followed up for 5 years to assess mortality and causes of death. All FPG determinations of the 3 years preceding the follow-up available in the clinical records were collected and analyzed. Patients were grouped in tertiles of mean FPG, CV-FPG, and the slope of FPG. These parameters of glucose control, as well as sex, age, duration of diabetes, insulin treatment, cigarette smoking, hypertension, and total cholesterol, were included in a multivariate analysis of mortality. During the follow-up, 63 men and 128 women died. Diabetes- and malignancy-related mortality were not independently associated with any parameter of glucose control, whereas cardiovascular-related mortality was independently associated with CV-FPG (P=.007) but not with the mean or the slope of FPG. In particular, the relative risk of cardiovascular mortality in subjects in tertile III versus tertile I of CV-FPG was 2.40 (95% CI, 1.28 to 4.53). CONCLUSIONS: These results indicate that FPG instability is a predictor of cardiovascular-related mortality in elderly patients with NIDDM and suggest that glucose stability might be a goal in the management of these patients.

Aged↗

PubMed1997

Comparative assessment of peripheral sympathetic function by postural vasoconstriction arteriolar reflex and sympathetic skin response in NIDDM patients.

PURPOSE: The aim of the study was to compare peripheral sympathetic adrenergic and cholinergic nerve function in NIDDM (non-insulin-dependent diabetes mellitus) patients with various degrees of diabetic neuropathy and neuropathic foot ulceration. The parameters used were postural vasoconstriction arteriolar reflex (VAR) and sympathetic skin response (SSR), respectively. PATIENTS AND METHODS: Forty-seven NIDDM patients were studied. No patients had clinically significant peripheral vascular disease. They were divided according to peripheral somatic neuropathy, assessed by clinical score and vibration perception threshold (VPT). Twenty-two patients showed no significant evidence of peripheral neuropathy and normal VPT (DN-); 15 had signs and symptoms of neuropathy and VPT alteration (DN+); 10 had diabetic neuropathy and foot ulceration (DNU). Twenty-two normal subjects were also examined as a control group. Resting arteriovenous shunt skin blood flow, measured using laser-Doppler flowmetry, and the VAR of the big toe on lowering the foot were studied. Sympathetic skin response was assessed by an EMG apparatus. Autonomic function was also investigated by using standard cardiovascular reflex tests. RESULTS: Resting blood flow values were similar in the three NIDDM groups and in the control group. VAR to foot lowering was significantly impaired in all NIDDM groups by comparison with controls (72.8 +/- 2.1%, mean +/- SEM), this impairment being progressively more pronounced in DN- (58.8 +/- 2.3%, P < 0.001), DN+ (33.3 +/- 3.0%, P < 0.001 versus DN-) and DNU (8.6 +/- 2.7%, P < 0.001 versus DN+). Sympathetic skin response was assessed in 28 patients and was significantly impaired in DN-compared with the control group (2.53 +/- 0.04 versus 2.71 +/- 0.04 log mcV, P < 0.01). This impairment was severe in the DNU compared with the DN+ group (1.36 +/- 0.05 versus 2.26 +/- 0.04 log mcV, P < 0.005). A positive correlation was found between VAR values and SSR (P < 0.001), and these measurements were also closely correlated with several parameters of central autonomic and somatic neuropathy. CONCLUSION: These results indicate that peripheral sympathetic adrenergic and cholinergic fibers simultaneously undergo early alterations in diabetic patients, even when there is no clinical neuropathy. Our data also show almost complete abolition of peripheral sympathetic activity in NIDDM patients with foot ulceration.

Blood Flow Velocity↗

PubMed1997

The role of insulin in age-related sex differences of cardiovascular risk profile and morbidity.

Metabolic changes and shifts in vascular risk profiles during and after menopause may partly explain the loss of premenopausal protection against cardiovascular disease (CVD). The current population-based survey addresses changes in risk factors and insulin levels across an age range of 40-79 years in men and women. Population recruitment was performed as part of the Bruneck Study from July to November 1990. In brief, of 1000 subjects randomly selected for inclusion 936 participated, with insulin measurements available in a random subgroup of 880 men and women, 60 of whom were excluded due to manifest diabetes mellitus. Insulin concentrations were assessed according to Hales and Randle and by a human insulin-specific radioimmunoassay. A rise in insulin concentrations with advancing age in women (5th-8th decade, 10.5-14.4 mU/l or +1.2%/year) contrasts with a marked gradual decline in insulin levels in men (5th-8th decade, 12.5-5.9 mU/l or -2.4%/year). Age trends of insulin concentrations in sexes emerged as independent of age-related changes in body weight, type of fat distribution, alcohol consumption, cigarette smoking, social status, fasting glucose, and physical activity (P < 0.001 for sex-specific difference in the regression slopes). Insulin levels in pre- and postmenopausal women of equal age differed significantly (10.1 vs. 13.9 mU/l, P = 0.003), thus advocating that variations of insulin observed may in part be related to shifts in sex hormone status. Levels of virtually all vascular risk attributes were lower in premenopausal women than in men of equal age, but the opposite was true for the elderly. The switch in the sex preponderance of vascular risk factors may be crucially involved in closing the CVD incidence gap between genders after menopause. The analysis suggests that variations in insulin levels are a common metabolic basis for sex/age trends in fasting glucose, apolipoprotein B, total cholesterol, total cholesterol/HDL cholesterol ratio, LDL density (LDL cholesterol/apolipoprotein B), triglycerides and systolic blood pressure.

Adult↗

PubMed1997

Relationship between fasting insulin and cardiovascular risk factors is already present in young men: the Verona Young Men Atherosclerosis Risk Factors Study.

The associations between fasting plasma insulin concentration and risk factors for cardiovascular disease were examined in 979 18-year-old men participating in the Verona Young Men Atherosclerosis Risk Factors Study, a cross-sectional population-based study. Body mass index (BMI), waist-to-hip ratio (WHR), plasma triglycerides and uric acid concentrations, and blood pressure values significantly increased, and the high-density lipoprotein (HDL)-total cholesterol ratio decreased, across quartiles of fasting insulin. Total and low-density lipoprotein cholesterol, concentrations did not change significantly with the increase in fasting insulin levels. After adjustment for BMI, WHR, smoking, alcohol intake and physical activity, only plasma triglycerides significantly increased across insulin quartiles (F = 7.1; P < 0.001). However, systolic blood pressure and uric acid were close to statistical significance (P = 0.06-0.07). Multiple linear regression analysis confirmed that plasma insulin was independently correlated with plasma triglycerides and, to a lesser extent, with blood pressure and uric acid concentration. This analysis pointed out that BMI was a stronger independent predictor of all cardiovascular disease risk factors than fasting insulin. When subjects were categorized according to the number of metabolic and haemodynamic disorders occurring within the same individual, subjects with multiple disorders (i.e, three or four) had higher plasma insulin levels than those with none or few disorders, even after adjusting for BMI, WHR and behavioural variables (F = 4.0; P < 0.01). These results indicate that hyperinsulinaemia is already associated with a cluster of cardiovascular disease risk factors in young adulthood, the strongest independent association being with plasma triglycerides.

Adolescent↗

PubMed1997

Obesity worsens cardiovascular risk profiles independently of hyperinsulinaemia.

OBJECTIVE: To investigate whether human obesity is characterized by a worse cardiovascular risk profile (than no obesity) even in the absence of hyperinsulinaemia. SUBJECTS AND DESIGN: A total of 367 healthy subjects (247 nonobese and 120 obese) with normal glucose tolerance and without family history of diabetes mellitus. INTERVENTIONS: A 75-g oral glucose tolerance test was performed in all participants. MAIN OUTCOME MEASURES: Anthropometry, blood pressure, fasting plasma lipids and urate, plasma glucose and insulin concentrations at fasting, 1 h and 2 h after oral glucose load. RESULTS: In a multivariate linear regression analysis, body mass index was strongly related to all cardiovascular risk factors, independently of sex, age and plasma insulin. When risk factors were compared in 37 normoinsulinaemic obese subjects (plasma insulin within one standard deviation of the mean values observed in the 247 nonobese subjects), and in 37 sex- and age-matched normoinsulinaemic nonobese subjects, we found that plasma glucose levels were similar in the two groups, whereas plasma triglyceride (1.50 +/- 0.13 vs. 1.13 +/- 0.08 mmol L-1; mean +/- SE), low-density lipoprotein cholesterol (3.42 +/- 0.25 vs. 2.77 +/- 0.18 mmol L-1) and urate (290 +/- 12 vs. 255 +/- 12 mumol L-1) levels were significantly higher, and plasma high-density lipoprotein cholesterol concentrations were lower (1.27 +/- 0.04 vs. 1.46 +/- 0.06 mmol L-1) in obese than in nonobese subjects with normal plasma insulin levels (P < 0.01). Also systolic (132 +/- 2 vs. 124 +/- 2 mmHg) and diastolic (86 +/- 1 vs. 81 +/- 1 mmHg) blood pressure values were significantly higher in normoinsulinaemic obese subjects than in normoinsulinaemic nonobese individuals (P < 0.001). CONCLUSIONS: These results suggest that in human obesity a worse cardiovascular risk profile is found (than in the nonobese) independently of the presence of hyperinsulinaemia.

Adult↗

PubMed1997

Relationship between insulin and carotid atherosclerosis in the general population. The Bruneck Study.

BACKGROUND AND PURPOSE: Although several studies have investigated the association between insulin and coronary heart disease, the relationship between this hormone and carotid atherosclerosis is not well established. METHODS: As a part of a population-based survey on atherosclerosis and its risk factors, serum insulin was measured at fasting (n = 888) and at 2 hours after an oral glucose load (n = 811; known diabetic subjects were excluded). The study population comprised an age- and sex-stratified random sample of men and women aged 40 to 79 years. Atherosclerosis in the common and internal carotid arteries was assessed twice (in 1990 and 1995) by duplex sonography. Progression during the 5-years follow-up was defined by an increase in the atherosclerosis score of more than the doubled measurement error (> 27%) or by the occurrence of new plaques. Subjects were stratified in quintiles according to baseline serum insulin at fasting or 2 hours after glucose loading. RESULTS: Logistic regression analysis revealed a significant association of carotid atherosclerosis with both low and high insulin (U-shaped relation). This finding was found before and after adjustment for several covariates (sex, age, body mass index, glucose tolerance, triglycerides, apolipoproteins Al and B, fibrinogen, blood pressure status, behavioral variables, and socioeconomic status). This relation applied equally to fasting and postglucose insulin and was more pronounced in the prospective analysis than in the cross-sectional analysis. CONCLUSIONS: We conclude that both "hypoinsulinemia" and hyperinsulinemia are independent risk indicators of carotid atherosclerosis.

Adult↗

PubMed1997

Cigarette smoking and insulin resistance in patients with noninsulin-dependent diabetes mellitus.

To evaluate the effects of chronic cigarette smoking on insulin sensitivity in patients with noninsulin-dependent diabetes mellitus (NIDDM), we examined 28 smokers and 12 nonsmokers with NIDDM, of similar sex, age, body mass index, waist/hip ratio, alcohol consumption, physical activity level, glycometabolic control, diabetes duration, and treatment. Insulin and C-peptide responses to oral glucose load were significantly higher in smokers than nonsmokers, whereas glucose levels were not substantially different. During insulin clamp (20 mU/min.m2), carried out in combination with tritiated glucose infusion and indirect calorimetry, total glucose disposal was markedly reduced in smokers vs. nonsmokers [19 +/- 1.2 vs. 33 +/- 5 mumol/min.kg fat-free mass (FFM); P < 0.001], in a dose-dependent fashion (F = 6.8, P < 0.001 by ANOVA when subjects were categorized for number of cigarettes smoked per day). Oxidative (9 +/- 1 vs. 14 +/- 2 mumol/min.kg FFM; P < 0.01) and nonoxidative (10 +/- 1 vs. 19 +/- 4 mumol/min.kg FFM; P < 0.01) pathways of insulin-mediated intracellular glucose metabolism were similarly reduced in smokers vs. nonsmokers. Plasma free fatty acid levels (240 +/- 33 vs. 130 +/- 23 microEq/L; P < 0.05) and lipid oxidation rate (1.39 +/- 0.1 vs. 0.95 +/- 0.2 mumol/ min.kg FFM; P < 0.05) were less suppressed by hyperinsulinemia in smokers than nonsmokers. In conclusion, chronic cigarette smoking seems to markedly aggravate insulin resistance in patients with NIDDM.

Adult↗

PubMed1997

Intimal-medial thickness of the carotid artery in nondiabetic and NIDDM patients. Relationship with insulin resistance.

OBJECTIVE: The aim of this study was 1) to compare intimal-medial thickness (IMT) of the carotid artery in nondiabetic and NIDDM patients and 2) to evaluate the association of this early marker of atherosclerosis with several cardiovascular risk factors, including plasma insulin and insulin resistance. RESEARCH DESIGN AND METHODS: A total of 58 nondiabetic and 56 NIDDM patients, randomly selected among those attending the outpatient Diabetes Clinic or the Clinic for Internal Medicine were examined. BMI, waist-to-hip ratio (WHR), blood pressure, glycohemoglobin (HbA1c), and fasting concentrations of plasma glucose, serum lipids (total and HDL cholesterol, triglycerides), and serum insulin were measured. Insulin resistance was assessed by computing glucose disappearance rate from plasma after intravenous insulin injection (Kitt). IMT of the carotid artery was measured by ultrasonography. RESULTS: IMT was significantly higher in diabetic patients, and the difference remained highly significant after adjusting for sex, age, BMI, WHR, presence of hypertension and dyslipidemia, and smoking status (1.39 vs. 1.24 mm, common SD 0.12, P < 0.001). Univariate regression analyses showed that IMT was negatively correlated with Kitt in either nondiabetic (r = -0.348, P < 0.01) or diabetic patients (r = -0.492, P < 0.001). However, multiple regression analyses showed that IMT was independently associated with age and WHR in nondiabetic subjects, whereas in diabetic patients, IMT was independently predicted by Kitt and hypertension. These two variables explained approximately 62% and approximately 35% of the variability of IMT in nondiabetic and diabetic patients, respectively. Plasma insulin was not independently associated with IMT in either groups. CONCLUSIONS: These results indicate that 1) diabetes is characterized by a greater thickness of the carotid artery independently of other established risk factor of atherosclerosis, 2) early atherosclerosis is independently associated with insulin resistance in diabetic but not in nondiabetic patients, 3) central adiposity is an independent predictor of IMT in nondiabetic individuals.

Anthropometry↗