Correlations between surrogate measures of insulin resistance and cardiovascular risk factors in obese and overweight patients

There are different equations to estimate insulin sensitivity by using OGTT with a reasonable approximation to whole body sensitivity obtained with the glucose clamp. Further work is needed to address their role in clinical practice as markers of the metabolic syndrome and predictors for cardiovascular disease. In the present study, we determined plasma glucose and insulin values during an OGTT test in 144 overweight and obese individuals. We assessed insulin resistance by the use of different equations and established their relationship with cardiovascular risk factors associated to the insulin resistance syndrome. Distributed the patients by quintiles of body mass index (BMI), the different surrogate measures clearly demonstrated that the more obese individuals were the most insulin resistant, a similar but not significant trend was observed related to the other cardiovascular risk factors. Efforts to use both fasting and post-load glucose and insulin concentrations to create indexes for routine use in clinical practice do not seem to be particularly useful in overweight or obese patients, as most of these patients will be insulin-resistant and insulin resistance is closely linked but not equal to the metabolic syndrome.     

Acute exercise improves postprandial cardiovascular risk factors in overweight and obese individuals

ObjectivesThe effects of 30 min of exercise on postprandial lipaemia in the overweight and obese are unknown as previous studies have only investigated bouts of at least 60 min in lean, healthy individuals. The aim of this study was to investigate whether a single 30-min bout of resistance, aerobic or combined exercise at moderate-intensity would decrease postprandial lipaemia, glucose and insulin levels as well as increase resting energy expenditure and increase fat oxidation following a high fat meal consumed 14 h after the exercise bout, in overweight and obese individuals compared to no exercise. We also compared the effects of the different exercise modalities.MethodsThis study was a randomized cross-over design which examined the postprandial effects of 30 min of different types of exercise in the evening prior to a breakfast meal in overweight and obese men and women. Participants were randomized on four occasions, each one-week apart, to each condition; either no exercise, aerobic exercise, resistance exercise or a combination of aerobic exercise and resistance exercise.ResultsAn acute bout of combination training did not have any significant effect on postprandial measurements compared to no exercise. However, aerobic exercise significantly reduced postprandial triglyceride levels by 8% compared to no exercise (p = 0.02) and resistance exercise decreased postprandial insulin levels by 30% compared to aerobic exercise (p = 0.01).ConclusionThese results indicate that a single moderate-intensity 30 min bout of aerobic or resistance exercise improves risk factors associated with cardiovascular disease in overweight and obese individuals.     

Resting energy expenditure, cardiovascular risk factors and insulin resistance in obese patients

OBJECTIVE: The aim of our study was to determine whether energy expenditure modified by increasing body mass over the wide range of body mass index (BMI) was related to insulin resistance, cardiovascular risk factors and dietary intakes. SUBJECTS AND METHODS: A population of 87 obese non-diabetic outpatients was analyzed prospectively. Indirect calorimetry, tetrapolar electrical bioimpedance, serial assessment of nutritional intake using written 3-day food records and biochemical analyses were performed. RESULTS: The mean age was 45.1 +/- 16.7 years and the mean BMI was 35.2 +/- 5.2. Indirect calorimetry showed a resting metabolic rate (RMR) of 1,732.2 +/- 406.6 kcal/day and oxygen consumption of 266.2 +/- 63.3 ml/min. RMR corrected by fat-free mass was 36.8 +/- 14.1 kcal/day/kg. Serial assessment of nutritional intake using written 3-day food records showed a calorie intake of 1,660 +/- 551.7 cal/day, a carbohydrate intake of 168.63 +/- 76.6 g/day, a fat intake of 72.1 +/- 26.42 g/day and a protein intake of 81.1 +/- 23.3 g/day. Insulin, HOMA, systolic blood pressure, diastolic blood pressure, waist circumference, fat mass, waist-to-hip ratio were higher in the third BMI tertile than in the first and second tertiles. No differences were detected in calorie intake, carbohydrate intake, fat intake, protein intake, drinking and alcoholic habit among BMI tertiles. RMR was similar in the different tertiles and the corrected RMR by fat-free mass was higher in first tertile than in the second and third tertiles (44.2 +/- 20.7 vs. 34.5 +/- 9.1 vs. 33.1 +/- 8.5 kcal/kg/day; p < 0.05). In multivariate analysis with a dependent variable (RMR), the fat-free mass remained in the model (F = 7.8; p < 0.05), with an increase of 10.1 (95% CI 3.6-17.5) kcal/day with each 1 kg of fat-free mass adjusted by age and sex. CONCLUSION: Resting energy expenditure in obese patients is not related to the BMI, insulin resistance and dietary intake. RMR is related to fat-free mass in a multivariant model.     

体脂分布类型和胰岛素抵抗对心血管病危险因素聚集性的 …

目的：探讨体脂分布类型和胰岛素抵抗对心血管病危险因素聚集性的影响。方法在自然人群中调查体重指数（ＢＭＩ）、腰围／臂围比值（ＷＨＲ）、血压、血胆固醇（ＴＣ）、甘油三酯（ＴＧ）、高密度脂蛋白－胆固醇（ＨＬＤ－Ｃ）、血糖（ＦＢＳ）、胰岛素（ＩＮＳ）及胰岛素敏感性指数（ＩＳＩ）。结果外周型超重组血压、ＴＧ、ＩＮＳ高于非超重组,ＨＤＬ－Ｃ、ＩＳＩ低于非超重组;而中心型超重组血压、ＩＮＳ及危险因素聚集程度高于     

Does physical activity reduce the risk of cardiovascular disease in overweight and obese individuals?

For individuals considered overweight or obese, physical activity or more structured exercise is recommended to facilitate weight loss and reduce risk of long-term disease. Physical activity and structured exercise programs, however, rarely result in significant loss of body weight or body fat, especially in women. Despite the minimal effect of exercise on weight loss, exercise has multiple health benefits for overweight and obese individuals, including skeletal muscle adaptations that improve fat and glucose metabolism and insulin action; enhanced endothelial function; favorable changes in blood lipids, lipoproteins, and hemostatic factors; and reductions in blood pressures, postprandial lipemia, and proinflammatory markers. These exercise-induced adaptations occur independently of changes in body weight or body fat. Thus, physically inactive individuals considered at increased risk for cardiovascular disease due to both sedentary lifestyle and a high body mass index should be encouraged to engage in regular physical activity, regardless of whether a more active lifestyle leads to weight loss.     

Social ecological correlates of physical activity in normal weight, overweight, and obese individuals

OBJECTIVE: Research is limited concerning the moderating influence of weight status (ie normal, over, and obese) on the social ecological correlates of physical activity (PA) in adults. Therefore, the present study attempted to shed light on this issue. DESIGN: In 2001, a national cross-sectional mail out panel survey was conducted over a 3-month period in the United States. SUBJECTS: There were 1867 normal weight (ie body mass index (BMI)=20-24.99 kg/m2), 2145 overweight (ie BMI=25-29.99 kg/m2), and 1902 obese (ie BMI>30 kg/m2) adults. MEASURES: Various demographic measurements were taken in addition to social support (SS), self-efficacy (SE), access to facilities, and PA. RESULTS: Normal weight individuals engaged in significantly more PA than overweight individuals, who in turn engaged in significantly more PA than obese individuals F(2,5991)=55.51, P<0.01. Further regression analyses showed that higher SE, SS, the access to facilities in a neighborhood, and various interactions among these constructs were significantly and positively associated with PA. Interestingly, the strength of these relationships varied depending on weight status. CONCLUSION: Weight status needs to be taken into consideration when examining social ecological correlates of PA.     

Albuminuria: Prevalence,associated risk factors and relationship with cardiovascular disease

Aims/Introduction

To investigate the prevalence and associated risk factors of microalbuminuria, and to explore the relationship between albuminuria and cardiovascular disease (CVD).

Materials and Methods

A nationally representative sample of 38,203 Chinese participants was categorized by different levels of urinary albumin‐to‐creatinine ratio (ACR; 0 –10 mg/g, 10 –20 mg/g, 20 –30 mg/g, 30 –300 mg/g). The prevalence of albuminuria was compared by using a single urinary ACR cut‐off point and by sex‐specific ACR cut‐off points. Factors associated with the presence of albuminuria, and the relationship between albuminuria and CVD were analyzed by logistic regression.

Results

Prevalence of albuminuria as measured by a single ACR cut‐point was significantly lower for men compared with women (13.9% vs 19.1% in the normal glucose tolerance group; 20.8% vs 26.8% in the impaired glucose tolerance group, P < 0.01). The prevalence of albuminuria, as measured by sex‐specific ACR cut‐points, was higher for men than women (31.4% vs 29.6% in the normal glucose tolerance group; 42.2% vs 39.3% in the impaired glucose tolerance group, P < 0.01). The independent risk factors for the presence of albuminuria were aging, female sex, hypertension, hyperglycemia, obesity, dyslipidemia, insulin resistance and metabolic syndrome. The subdivided normal ACR group did not show a linear or statistically significant relationship with CVD after adjusting for conventional CVD risk factors (P > 0.05).

Conclusions

The prevalence of albuminuria was high in the general Chinese population. Aging, female sex, hypertension, hyperglycemia, dyslipidemia, insulin resistance, obesity and metabolic syndrome were all independent risk factors for albuminuria. The causal relationship between ACR and CVD might require further follow‐up investigation.     

Surrogate indexes vs. euglycaemic-hyperinsulinemic clamp as an indicator of insulin resistance and cardiovascular risk factors in overweight and obese postmenopausal women

BACKGROUND: There is considerable interest in validating the most convenient method to estimate insulin sensitivity in clinical research protocols that could best indicate cardiovascular risk factors. To address this issue we examined the interrelationships of several cardiovascular risk factors with surrogate indexes such as fasting insulin, the homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI) and the revised QUICKI vs the euglycaemic-hyperinsulinemic (EH) clamp in a non-diabetic overweight or obese postmenopausal female population. DESIGN: Cross-sectional study involving 88 obese postmenopausal women (age: 57.5+/-5.0 yrs; body mass index: 32.52+/-4.4 kg/m2; percent body fat: 46.35+/-4.9%). METHODS: Insulin sensitivity was determined by the EH clamp technique as well as by surrogate indexes such as fasting insulin, HOMA, log HOMA, QUICKI and revised QUICKI. Body composition and body fat distribution were measured using dual energy x-ray absorptiometry and computed tomography, respectively. RESULTS: Correlations between insulin resistance indexes (fasting insulin, revised QUICKI, QUICKI, log HOMA, HOMA) vs glucose disposal were similar (range of r's=0.40 to 0.49), suggesting that no index was superior to another with respect to its relationship with the EH clamp. Correlations between the insulin resistance indexes with plasma lipids were comparable among all indexes, however, systolic blood pressure, visceral fat and C-reactive protein were moderately superior with index vs the EH clamp. CONCLUSION: Surrogate measures of insulin resistance, in particular fasting insulin, are simple tools appropriate for epidemiological studies that can be used as substitutes for the EH clamp to estimate glucose disposal and cardiovascular risk factors in overweight and obese postmenopausal women.     

The relationship between insulin resistance and cardiovascular risk factors in overweight/obese non-diabetic Asian adults: the 1992 Singapore National Health Survey

OBJECTIVE: Insulin resistance (IR) is associated with cardiovascular risk factors including hypertension, dyslipidemia, glucose intolerance and hyperuricemia. The relationship between IR and these cardiovascular risk factors in obese non-diabetic individuals is not well studied. We explore this relationship by comparing the cardiovascular risk factors among insulin-sensitive and insulin-resistant overweight/obese non-diabetic Asian adults in the 1992 National Health Survey of Singapore. DESIGN AND MEASUREMENTS: A total of 3568 subjects were examined in the survey, which involved a combination of disproportionate stratified sampling and systematic sampling. Anthropometric measurements, level of physical activity, blood pressure, insulin, lipid profile, uric acid and standard 75 g oral glucose tolerance test were performed after a 10 h overnight fast. Subjects with diabetes were excluded from the analysis. Homeostasis model assessment (HOMA) was used to assess insulin sensitivity. Relative LDL size was derived from the formula LDL/ApoB. We defined insulin-sensitive individuals as having a HOMA value <1.479 (below median in individuals without diabetes; n=3226) and overweight/obesity as body mass index (BMI) >or=25.0 kg/m(2). RESULTS: There were 156 insulin-sensitive (S) and 679 insulin-resistant (R) overweight/obese individuals, respectively. The groups did not differ in terms of gender and ethnic distribution and level of physical activity. However, subjects in group S were younger than those in group R (mean+/-s.d.; 40.1+/-12.1 vs 42.4+/-12.7 y; P<0.05). Group R individuals were also slightly more obese globally and centrally than group S (BMI=28.2+/-3.2 vs 27.1+/-2.8 kg/m(2); waist circumference (WC)=86.7+/-9.3 vs 82.5+/-8.3 cm; P<0.01). There were more subjects with impaired glucose tolerance (IGT) in group R than in group S (29.7 vs 16.0%; P<0.01). After adjustment for age and indices of global and regional obesity (ie BMI and WC), insulin-resistant individuals showed higher apolipoprotein B, triglyceride, fasting (FPG) and 2 h post-load plasma glucose (2hPG) but lower HDL and LDL size. Further adjustment for FPG, 2hPG and level of physical activity had minimal impact on the results. CONCLUSIONS: Insulin-resistant overweight/obese non-diabetic Asian adults had greater burden of the cardiovascular dysmetabolic syndrome than insulin-sensitive overweight/obese individuals. This could not be fully explained by differences in global and regional obesity, glucose tolerance and level of physical activity.     

Hyperleptinemia is associated with hypertension, systemic inflammation and insulin resistance in overweight but not in normal weight men

Background and AimHigh leptin (LPT) is associated with high blood pressure (BP), insulin resistance and systemic inflammation but also excess body weight and adiposity. To disentangle these multiple relations, we analyzed BP, HOMA and circulating C-reactive protein concentration (hs-CRP) in white male adults with different LPT levels but similar age, body mass index (BMI) and body fat distribution. The novel aspect is the different statistical approach used to investigate the relation between LPT and the other alterations present in obesity.Methods and Results972 Olivetti Heart Study participants were stratified according to the median LPT distribution (2.97 ng/ml) into low LPT (l-LPT) and high LPT (h-LPT). The two groups were then carefully matched for age and BMI. We identified two groups of 207 h-LPT and 207 l-LPT individuals with overlapping age, BMI and waist/hip ratio. The two groups had different BP (132.9 ± 16.2/85.7 ± 9.0 vs 128.7 ± 18.2/82.8 ± 9.8 mmHg, p = 0.014 for SBP and p = 0.002 for DBP) and prevalence of hypertension (57% vs 43%, p = 0.027). Upon separate evaluation of untreated individuals with BMI < 25 or BMI ≥ 25, within the latter subgroup h-LPT compared with l-LPT participants (n = 133 each group) had higher BP (p = 0.0001), HOMA index (p = 0.013), hs-CRP (p = 0.002) and heart rate (p = 0.008) despite similar age and BMI. By contrast, within the normal weight subgroup, h-LPT individuals did not differ from l-LPT (n = 37 each) for any of these variables.ConclusionsHigh LPT is associated with higher BP, HR, hs-CRP and HOMA index independently of BMI and fat distribution but only among overweight individuals.     

减体重对肥胖和超重者心血管病危险因素的影响

目的：探讨对肥胖和超重者的减肥对心血管危险因素的影响。方法：对41名肥胖和超重者采取6周封闭管理的集中减肥，控制饮食，进行运动训练，每2周测定体重、腰臀围等指标，减肥前、后进行空腹血脂、血糖、血胰岛素、血转氨酶及肝脏超声检查。结果：通过6周减肥，受试者的体重、体重指数、腰围、臀围、腰臀围比、皮褶厚度、体脂含量及百分比、静息血压、心率呈非常明显的下降（P〈0．001）：减肥后血丙氨酸氨基转移酶、甘油三酯、胰岛素及胰岛素抵抗指数明显下降（P〈0．05-〈0．001），血高密度脂蛋白-胆固醇明显升高（P〈0．001），脂肪肝显著改善（P=0．001）。结论：运动锻炼结合饮食控制可减轻肥胖和超重者的体重，有效降低心血管疾病的危险因素。     

Ethnic differences in metabolic cardiovascular risk among normal weight individuals: Implications for cardiovascular risk screening. The HELIUS study

Background and aims

Cardiovascular disease (CVD) risk factors may occur among a substantial proportion of normal weight individuals, particularly among some ethnic minorities. It is unknown how many of these individuals would be missed by commonly applied eligibility criteria for cardiovascular risk screening. Thus, we aim to determine cardiovascular risk and eligibility for cardiovascular risk screening among normal weight individuals of different ethnic backgrounds.

Relationship between insulin resistance, weight loss, and coronary heart disease risk in healthy, obese women.

Several popular books have recently been published stating that being insulin-resistant favors weight gain and/or prevents weight loss. Because this view seems to have gained widespread support in the general population, we thought it important to perform the current study testing the hypothesis that differences in insulin-mediated glucose disposal do not affect weight loss in response to calorie-restricted diets. For this purpose, we studied the change in weight and risk factors for coronary heart disease (CHD) in healthy women volunteers, defined as being obese on the basis of a body mass index (BMI) greater than 30.0 kg/m(2). The insulin suppression test was used to stratify obese women at baseline into insulin-resistant and insulin-sensitive subgroups on the basis of their steady-state plasma glucose (SSPG) concentration at the end of a 180-minute infusion of octreotide, exogenous insulin, and glucose. They were then instructed on a calorie-restricted diet plus sibutraminine (15 mg/day) for a total period of 4 months. Baseline measurements also included determination of fasting lipid and lipoprotein concentrations, and hourly (8 AM to 4 PM) determinations of plasma glucose and insulin concentrations before and after breakfast and lunch. Twenty-four women completed the 4-month period of calorie restriction: 13 classified as insulin-resistant (SSPG = 219 +/- 7 mg/dL) and 11 as insulin-sensitive (SSPG = 69 +/- 6 mg/dL). The insulin-resistant group also had higher (P =.03) plasma triglyceride (TG) concentrations and a higher ratio of total to high-density lipoprotein (HDL) cholesterol concentration (P =.02) at baseline. Both groups lost a significant amount of weight during the study, and there was no difference between the weight loss in the insulin-resistant (8.6 +/- 1.3 kg) and insulin-sensitive (7.9 +/- 1.4 kg) groups. Weight loss in the insulin-resistant group was also associated with a significant decrease in SSPG concentration (219 +/- 7 to 144 +/- 14 mg/dL), associated with significantly lower fasting TG concentrations (P <.001) and day-long concentrations of plasma glucose and insulin (P <.005). None of these variables changed in the insulin-sensitive group. These results indicate that: (1) CHD risk factors in obese women vary as a function of being insulin-resistant or insulin-sensitive; (2) dramatic variations in insulin-mediated glucose disposal do not modulate weight loss in response to calorie-restricted diets, and (3) weight loss is effective in reducing CHD risk in insulin-resistant, obese women. Given these data, it seems obvious that attempts to reduce CHD risk factors by weight loss should focus on obese individuals who are also insulin-resistant.     

Association between liver insulin resistance and cardiovascular risk factors

Abstract. Vangipurapu J, Stan?áková A, Kuulasmaa T, Soininen P, Kangas AJ, Ala‐Korpela M, Kuusisto J, Laakso M (University of Eastern Finland and Kuopio University Hospital, Kuopio; University of Oulu and Biocenter Oulu, Oulu, Finland). Association between liver insulin resistance and cardiovascular risk factors. J Intern Med 2012; 272: 402–408. Objectives. The objective of this study was to examine the associations between indices of liver insulin resistance (IR) and whole‐body insulin sensitivity and different cardiovascular disease (CVD) risk factors. Design and subjects. A total of 8750 nondiabetic men (age 57.2 ± 7.1 years, body mass index 26.8 ± 3.8 kg m^?2) were included in this study from the population‐based cross‐sectional Metabolic Syndrome In Men (METSIM) cohort. Liver IR index and Matsuda insulin sensitivity index (ISI) were used as markers of liver IR and whole‐body insulin sensitivity, respectively. Pearson correlation analysis was performed to examine the associations between these indices and various CVD risk factors. Results. Total cholesterol (r = ?0.088 vs. r = 0.020; P < 0.0019), high‐sensitivity C‐reactive protein (CRP) (r = 0.284 vs. r = ?0.219; P < 0.0019) and total triglycerides (r = 0.507 vs. r = ?0.477; P < 0.05) were more highly correlated with liver IR index than with Matsuda ISI. By contrast, Matsuda ISI was nominally more highly correlated with systolic and diastolic blood pressure (r = ?0.234 and r = ?0.275 vs. r = 0.202 and r = 0.239, respectively) compared to liver IR index. Furthermore, the variance explained by liver IR index was larger than that explained by Matsuda ISI for the majority of CVD risk factors measured. Conclusions. Liver IR index correlated more strongly than Matsuda ISI with levels of total cholesterol, CRP and triglycerides. Therefore, liver IR might be a significant indicator of CVD risk amongst men.