Body Fat Is Associated With Reduced Aortic Stiffness Until Middle Age

Adiposity, obesity, and arterial aging: longitudinal study of aortic stiffness in the Whitehall II cohort

We sought to determine whether adiposity in later midlife is an independent predictor of accelerated stiffening of the aorta. Whitehall II study participants (3789 men; 1383 women) underwent carotid-femoral applanation tonometry at the mean age of 66 and again 4 years later. General adiposity by body mass index, central adiposity by waist circumference and waist:hip ratio, and fat mass percent by body impedance were assessed 5 years before and at baseline. In linear mixed models adjusted for age, sex, ethnicity, and mean arterial pressure, all adiposity measures were associated with aortic stiffening measured as increase in pulse wave velocity (PWV) between baseline and follow-up. The associations were similar in the metabolically healthy and unhealthy, according to Adult Treatment Panel-III criteria excluding waist circumference. C-reactive protein and interleukin-6 levels accounted for part of the longitudinal association between adiposity and PWV change. Adjusting for chronic disease, antihypertensive medication and risk factors, standardized effects of general and central adiposity and fat mass percent on PWV increase (m/s) were similar (0.14, 95% confidence interval: 0.05-0.24, P=0.003; 0.17, 0.08-0.27, P<0.001; 0.14, 0.05-0.22, P=0.002, respectively). Previous adiposity was associated with aortic stiffening independent of change in adiposity, glycaemia, and lipid levels across PWV assessments. We estimated that the body mass index-linked PWV increase will account for 12% of the projected increase in cardiovascular risk because of high body mass index. General and central adiposity in later midlife were strong independent predictors of aortic stiffening. Our findings suggest that adiposity is an important and potentially modifiable determinant of arterial aging.

Inverse Relationship between Cardio-Ankle Vascular Index and Body Mass Index in Healthy Children

OBJECTIVE

To establish reference scores for cardio-ankle vascular index (CAVI), a noninvasive measure of vascular function, which reflects the stiffness of arteries, in healthy children, to test for racial and ethnic differences, and to compare CAVI scores between overweight and normal weight children.

STUDY DESIGN

Subjects included 292 children aged 10-18 years: 100 non-Hispanic whites, 89 non-Hispanic blacks, and 103 Hispanics. Subjects were grouped as normal weight (body mass index [BMI] <85th percentile for age) and overweight (BMI >85th percentile for age). Blood pressure (BP) and CAVI scores were measured in all subjects.

RESULTS

After controlling for age, sex, and BMI, normal weight black males had a higher CAVI score (indicating stiffer arteries) in comparison with Hispanic males and white males (5.53 ± 0.15 vs 5.13 ± 0.15 vs 5.02 ± 0.15, P = .04). BMI had an inverse association on the CAVI score (r = -0.335, P < .0001). In multivariable analysis, BMI and average CAVI scores were significant predictors of each other (R(2) = 0.37, P < .0001, R(2) = 0.21, P < .0001). There was no significant correlation between CAVI scores and resting BP values, confirming that CAVI scores were independent of concurrent BP values.

CONCLUSIONS

Significant differences in vascular function exist among ethnic groups of children. Overweight children had lower CAVI scores, suggestive of vascular adaptation to obesity in early life. CAVI, by providing a noninvasive measure of vascular health, may help identify children at increased risk for cardiovascular disease.

Estimation of aortic pulse wave transit time in cardiovascular magnetic resonance using complex wavelet cross-spectrum analysis

BACKGROUND

Aortic pulse wave velocity (PWV), which substantially increases with arterial stiffness and aging, is a major predictor of cardiovascular mortality. It is commonly estimated using applanation tonometry at carotid and femoral arterial sites (cfPWV). More recently, several cardiovascular magnetic resonance (CMR) studies have focused on the measurement of aortic arch PWV (archPWV). Although the excellent anatomical coverage of CMR offers reliable segmental measurement of arterial length, accurate transit time (TT) determination remains a challenge. Recently, it has been demonstrated that Fourier-based methods were more robust to low temporal resolution than time-based approaches.

METHODS

We developed a wavelet-based method, which enables temporal localization of signal frequencies, to estimate TT from ascending and descending aortic CMR flow curves. This method (archPWVWU) combines the robustness of Fourier-based methods to low temporal resolution with the possibility to restrict the analysis to the reflectionless systolic upslope. We compared this method with Fourier-based (archPWVF) and time domain upslope (archPWVTU) methods in relation to linear correlations with age, cfPWV and effects of decreasing temporal resolution by factors of 2, 3 and 4. We studied 71 healthy subjects (45 ± 15 years, 29 females) who underwent CMR velocity acquisitions and cfPWV measurements.

RESULTS

Comparison with age resulted in the highest correlation for the wavelet-based method (archPWVWU:r = 0.84,p < 0.001; archPWVTU:r = 0.74,p < 0.001; archPWVF:r = 0.63,p < 0.001). Associations with cfPWV resulted in the highest correlations for upslope techniques whether based on wavelet (archPWVWU:r = 0.58,p < 0.001) or time (archPWVTU:r = 0.58,p < 0.001) approach. Furthermore, while decreasing temporal resolution by 4-fold induced only a minor decrease in correlation of both archPWVWU (r decreased from 0.84 to 0.80) and archPWVF (r decreased from 0.63 to 0.51) with age, it induced a major decrease for the archPWVTU age relationship (r decreased from 0.74 to 0.38).

CONCLUSIONS

By CMR, measurement of aortic arch flow TT using systolic upslopes resulted in a better correlation with age and cfPWV, as compared to the Fourier-based approach applied on the entire cardiac cycle. Furthermore, methods based on harmonic decomposition were less affected by low temporal resolution. Since the proposed wavelet approach combines these two advantages, it might help to overcome current technical limitations related to CMR temporal resolution and evaluation of patients with highly stiff arteries.

Abdominal obesity is associated with arterial stiffness in middle-aged adults

BACKGROUND AND AIMS

The relation between adiposity and arterial stiffness remains controversial. We determined whether abdominal and visceral adipose tissue may be a better predictor of arterial stiffness than general obesity in middle-aged adults.

METHODS AND RESULTS

A total of 146 participants (76 men, 70 women; 50 years) were studied. The automatic vascular screening device (Omron VP-1000plus) was used to measure blood pressure simultaneously in the arms and ankles and to determine arterial stiffness by pulse wave velocity (PWV). Using multiple linear regressions, the relations between indicators of obesity and arterial stiffness were examined after adjustment for confounders. Both carotid-femoral PWV and brachial-ankle PWV were significantly associated with BMI (both P < 0.05) but not with body fat percentage. Measures of abdominal obesity, including waist circumference and visceral fat mass (via DXA), were strongly associated with PWV and remained positively associated with arterial stiffness after adjustment for age and gender. Cardiovascular fitness as assessed by maximal oxygen consumption was related to body fat percentage but not with visceral fat. More favorable cardiovascular health profile was associated with both lower visceral fat mass and PWV (both P < 0.001).

CONCLUSION

Abdominal obesity and visceral fat are associated with large artery stiffness. These findings support the importance of adiposity measures as a risk factor for arterial stiffening in middle-aged adults.

Carotid-femoral pulse wave velocity is not increased in obesity

BACKGROUND

There are conflicting results in the literature concerning the relationship between obesity and arterial stiffness, assessed by carotid-femoral pulse wave velocity (PWV). The discrepancies could be due to differences in carotid-femoral distance measurement and/or to the presence of pathologies frequently associated with obesity and which increase arterial stiffness. In this study, we examine the relationship between PWV and weight, without and with associated cardiovascular risk factors (diabetes and/or dyslipidemia).

METHODS

PWV was assessed with a Complior SP device (Alam Medical, France) in 2,034 patients referred for ambulatory blood pressure monitoring. The carotid-femoral distance used to calculate PWV was measured with a flexible tape and from the estimated straight carotid-femoral distance obtained with a published equation.

RESULTS

In the whole cohort, PWV did not differ significantly according to weight (9.6±2.1, 9.8±2.2 and 9.7±1.9 m/s in normal weight, overweight and obese subjects, respectively, with the distance measured with a tape). PWV was significantly higher in the four groups of patients with cardiovascular risk factors (e.g., 11.1±2.4, 11.0±2.7 and 10.4±2.0 m/s in normal weight, overweight, and obese subjects, respectively, in the group treated for diabetes and dyslipidemia) than in the group of patients without cardiovascular risk factors (8.5±1.6, 8.8±1.7 and 8.5±1.2 in normal weight, overweight, and obese subjects, respectively). There was no relationship between PWV value and weight status, whether or not there were cardiovascular risk factors, and whatever the distance used to calculate PWV.

CONCLUSIONS

In our cohort, obesity per se was not associated with increased arterial stiffness.

Prevalence of High Arterial Stiffness and Gender-specific Differences in the Relationships with Classical Cardiovascular Risk Factors

AIM

To investigate the relationships between arterial stiffness and classic cardiovascular risk factors with respect to gender differences in addition to the prevalence of high arterial stiffness in Chongqing, China based on an examination of 18,336 subjects.

METHODS

The cardio-ankle vascular index was used as a marker of arterial stiffness. The relationships between arterial stiffness and body mass index (BMI) as well as metabolic syndrome (MetS) were estimated using logistic regression models.

RESULTS

The prevalence of high arterial stiffness was 12.74% in men and 9.91% in women. For age and BMI, compared with the reference group, men had higher adjusted odds ratios (ORs) in each group versus their female counterparts. For each individual index of MetS, the effects of waist circumference and systolic blood pressure (SBP) on high arterial stiffness exhibited remarkable gender differences, with women having higher ORs and adjusted ORs than men. As the sum of MetS traits increased, the ORs and adjusted ORs in the subjects also increased, with women having higher values than men in each group.

CONCLUSIONS

Gender-specific differences exist in the prevalence of high arterial stiffness among subjects compared by age, BMI and MetS, with varying effects of influence for these factors between genders.

Weight reduction and aortic stiffness in obese children and adolescents: a 1-year follow-up study

Little is known about the effect of weight reduction on aortic stiffness and especially so in the young. The present study investigates whether weight reduction influences aortic stiffness in obese children and adolescents. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart rate 75 (AIx@HR75) were measured in 72 obese patients aged 10-18 years at baseline and after 1-year of lifestyle intervention (follow-up). We found that although the degree of obesity decreased (Δbody mass index z-score: -0.24±0.45, P<0.0001), cfPWV was higher at follow-up (ΔcfPWV: 0.27±0.47 m s(-1), P<0.0001), which was explained by the increase in age (β=0.12 ms(-1)  per year, 95% confidence interval (CI) 0.07-0.17, P<0.0001) and partly by changes in mean arterial pressure and heart rate. Changes in cfPWV were not related to changes in obesity measures. No significant change was found in AIx@HR75 (ΔAIx@HR75: 2.10±9.73%, P=0.072), but changes in AIx@HR75 were related to changes in abdominal fat (Δwaist/height ratio: β=50.3, 95% CI 6.7-94.0, P=0.02) and changes in total body fat percent by dual energy X-ray absorptiometry scan (Δtotal body fat (%): β=0.7, 95% CI 0.1-1.3, P=0.02) when adjusted for gender and relevant baseline confounders. In conclusion, no clear effect of weight reduction was found on aortic stiffness, although changes in AIx@HR75 were associated with changes in both abdominal fat and total body fat percent. The higher cfPWV at follow-up was related to the older age.

High body fat and low muscle mass are associated with increased arterial stiffness in Asian Indians in North India

AIM

To investigate the associations of high body fat and low muscle mass with arterial stiffness in Asian Indians with type 2 diabetes mellitus (T2DM) in North India.

METHODS

In this cross sectional study, subjects with T2DM (males n=110, females n=58, mean age: 53.8±10.0years) were recruited. Anthropometry and body composition analysis were performed and measures of glycemia, lipids and PWV were analyzed.

RESULTS

Significant positive correlation was observed between PWV and body fat (p<0.05), left leg fat (p<0.05), and right leg fat (p<0.01) percentages only in females. In males, significant negative correlation was observed between PWV and truncal fat free mass (p<0.05) and fat free mass in right arm (p=0.05) and left arm (p<0.05). In both males and females, significant negative correlation was observed between PWV and fat free mass in left leg (p<0.01) and for right leg fat free mass only in females.

CONCLUSION

Excess adiposity and low fat free mass are associated with arterial stiffening in Asian Indians with T2DM in North India, with significant gender differences.

Inverse association between central obesity and arterial stiffness in Korean subjects with metabolic syndrome: a cross-sectional cohort study

BACKGROUND

Metabolic syndrome (MetS) is associated with increased risks of diabetes and atherosclerotic cardiovascular disease. Whether central obesity (CeO) is a prerequisite for the diagnosis of MetS in the International Diabetes Federation (IDF) definition is a substantial issue because it may influence the clinical value of MetS for predicting subclinical atherosclerosis.

METHODS

We investigated the relation between MetS, as defined by the National Cholesterol Education Program-Adult Treatment Panel (NCEP-ATP) III criteria, and arterial stiffness according to CeO status in 2,560 healthy Korean subjects who participated in a community-based cohort study. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV).

RESULTS

The prevalence of MetS was 37%; 84% of MetS subjects had CeO. The prevalence of diabetes was significantly higher in MetS subjects than in non-MetS subjects (30 vs. 8%, p <0.001). The number of MetS components was significantly correlated with baPWV (r = 0.311, p <0.001). In a subgroup analysis of MetS subjects, the prevalence of diabetes was not significantly different in MetS subjects with and without CeO. MetS subjects without CeO had significantly higher baPWV than those with CeO (1654 ± 315 vs. 1578 ± 270 cm/s, p = 0.002). Multiple regression models revealed that waist circumference was independently associated with decreased baPWV in MetS subjects.

CONCLUSIONS

Despite the significant correlation between the number of MetS components and arterial stiffness, there appeared to be an inverse association between CeO and arterial stiffness in MetS subjects. In contrast to the IDF definition, our findings suggest that CeO is not crucial for the diagnosis of MetS in otherwise healthy Koreans having multiple metabolic risk factors with respect to subclinical atherosclerosis reflected in arterial stiffness.

Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

BACKGROUND

Insulin resistance has been related to elevated blood pressure (BP) in obese children and may adversely affect the vasculature by arterial stiffening. The objective was to investigate whether daytime and nighttime BP were elevated and related to insulin resistance and arterial stiffness in obese children and adolescents.

METHODS

Ninety-two obese patients aged 10-18 years were compared with 49 healthy control individuals. Insulin resistance was measured as the homeostatic assessment model (HOMA), and arterial stiffness was measured as carotid-femoral pulse wave velocity (cfPWV).

RESULTS

Mean ± SD daytime systolic BP (SBP) (obese: 125±8.3mm Hg; control: 121±10.1mm Hg; P = 0.03) and nighttime SBP (obese: 108±10.7mm Hg; control: 102±8.2mm Hg; P = 0.0001) were higher in the obese group when compared with the control group. No difference was found in daytime diastolic BP (DBP), whereas nighttime DBP (obese: 60±6.6mm Hg; control: 57±4.8mm Hg; P = 0.001) and night-to-day BP ratios were higher in the obese group. Nighttime SBP was related to BMI z score (β = 6.0; 95% confidence interval (CI) = 2.9-9.1; P = 0.0002) and waist/height ratio (β = 36.7; 95% CI = 5.6-67.9; P = 0.02) in the obese group. HOMA index (obese: median = 3.7, interquartile range (IQR) = 2.3-6.0; control: median = 2.6, IQR = 1.8-3.4; P = 0.002) was higher, whereas cfPWV (obese: 4.8±0.8 m/s; control: 5.1±0.6 m/s; P = 0.03) was lower in the obese group. CfPWV was not related to logHOMA index. In multiple regression analyses, the higher nighttime BP in the obese group was independent of logHOMA and cfPWV.

CONCLUSIONS

Obese children had a higher nighttime BP when compared with the control group independently of insulin resistance and arterial stiffness. No relationship was found between insulin resistance and arterial stiffness. CLINICAL TRIAL REGISTRATION Clinicaltrials.gov identifier NCT01310088.

Sex and race (black-white) differences in the relationship of childhood risk factors to adulthood arterial stiffness: the Bogalusa Heart Study

BACKGROUND

Cardiovascular risk factors in childhood are predictive of adulthood arterial stiffness. However, it is unknown whether this relationship varies by race or sex.

METHODS

Six hundred and eighty adults aged 24 to 43 had been followed for an average of 26.3 years, from the Bogalusa Heart Study. Brachial to ankle pulse wave velocity (baPWV) measured by an automatic oscillometric technique was used as the outcome variable for arterial stiffness during adulthood. Body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, and systolic blood pressure (SBP), all measured in childhood, were used as predictors. The average values of childhood measurements at multiple time points were used, standardized to age, race, and sex-specific z-scores.

RESULTS

In the total sample, childhood SBP was the only significant predictor (P < 0.001) for adult baPWV. Significant interactions between sex and BMI (P = 0.001), between sex and LDL-C (P = 0.035), and between race and HDL-C (P = 0.002) on adult baPWV were identified. Childhood predictors of adult baPWV were BMI (30.9 cm/s reduction in baPWV per standard deviation increase, 95% confidence interval [CI]: -55.0, -6.9 cm/s), LDL-C (30.8 cm/s increase, 95% CI: 2.9, 59.5 cm/s), and HDL-C (46.8 cm/s reduction, 95% CI: -76.2, -17.4 cm/s) in white males; SBP (38.2 cm/s increase, 95% CI: 11.0, 65.4 cm/s) in white females; BMI (71.3 cm/s reduction, 95% CI: -119.9, -22.7 cm/s) in black males; and none in black females.

CONCLUSIONS

The associations of childhood cardiovascular risk factors with adult arterial stiffness varied by race and sex.

The impact of change in physical activity on change in arterial stiffness in overweight or obese sedentary young adults

Arterial stiffness is associated with cardiovascular events and mortality. Lifestyle factors such as physical activity (PA) may reduce arterial stiffness. The purpose of this study is to determine the impact of change in PA on 1-year change in arterial stiffness in 274 overweight/obese sedentary young adults. The Slow Adverse Vascular Effects of excess weight (SAVE) trial was a study evaluating the relationships between weight loss, dietary sodium, and vascular health. PA was measured with the ActiGraph AM7164 accelerometer. Intensity of activity was determined using established cut-points. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV) using an automated device. Analysis of covariance compared changes in total accelerometer counts, minutes/day in light-intensity PA (LPA), moderate-to-vigorous PA (MVPA), and sedentary time, by categories of change in baPWV. Models were adjusted for time since baseline visit, age, sex, race, homeostatis model of assessment of insulin resistance, mean arterial pressure, heart rate, and weight change. Total accelerometer counts and time spent in MVPA increased from baseline to 12 months while time spent in LPA significantly decreased. Mean baPWV was similar at each time point. Those who showed decreased baPWV also showed an increase in total accelerometer counts per day and time spent in MVPA in the fully adjusted models (p<0.001). Changes in sedentary time and time spent in LPA were not associated with changes in baPWV. These results indicate that even modest increases in MVPA can reduce arterial stiffness, a risk factor for future cardiovascular events.

Dichotomous mechanisms of aortic stiffening in high-fat diet fed young and old B6D2F1 mice

Abstract Advancing age is associated with increased stiffness of large elastic arteries as assessed by aortic pulse wave velocity (PWV). Greater PWV, associated with increased risk of cardiovascular diseases, may result from altered expression of the extracellular matrix proteins, collagen and elastin, as well as cross-linking of proteins by advanced glycation end products (AGEs). Indeed, aortic PWV is greater in old (28-31 months) normal chow (NC, 16% fat by kcal)-fed male B6D2F1 mice compared with young (Y: 5-7 months) NC-fed mice (397 ± 8 vs. 324 ± 14 cm/s, P < 0.05). Aging also induces a ~120% increase in total aortic collagen content assessed by picosirius red stain, a ~40% reduction in medial elastin assessed by Verhoeff's Van Geison stain, as well as a 90% greater abundance of AGEs in the aorta (P < 0.05). The typical American diet contains high dietary fat and may contribute to the etiology of arterial stiffening. To that end, we hypothesized that the age-associated detriments in arterial stiffening are exacerbated in the face of high dietary fat. In young animals, high-fat (40% fat by kcal) diet increases aortic stiffness by 120 ± 18 cm/s relative to age-matched NC-fed mice (P < 0.001). High-fat was without effect on aortic collagen or AGEs content in young animals; however, elastin was greatly reduced (~30%) after high-fat in young mice. In old animals, high-fat increased aortic stiffness by 108 ± 47 cm/s but was without effect on total collagen content, medial elastin, or AGEs. These data demonstrate that both aging and high-fat diet increase aortic stiffness, and although a reduction in medial elastin may underlie increased stiffness in young mice, stiffening of the aorta in old mice after high-fat diet does not appear to result from a similar structural modification.

Metabolic mediators of the effects of body-mass index, overweight, and obesity on coronary heart disease and stroke: a pooled analysis of 97 prospective cohorts with 1·8 million participants

BACKGROUND

Body-mass index (BMI) and diabetes have increased worldwide, whereas global average blood pressure and cholesterol have decreased or remained unchanged in the past three decades. We quantified how much of the effects of BMI on coronary heart disease and stroke are mediated through blood pressure, cholesterol, and glucose, and how much is independent of these factors.

METHODS

We pooled data from 97 prospective cohort studies that collectively enrolled 1·8 million participants between 1948 and 2005, and that included 57,161 coronary heart disease and 31,093 stroke events. For each cohort we excluded participants who were younger than 18 years, had a BMI of lower than 20 kg/m(2), or who had a history of coronary heart disease or stroke. We estimated the hazard ratio (HR) of BMI on coronary heart disease and stroke with and without adjustment for all possible combinations of blood pressure, cholesterol, and glucose. We pooled HRs with a random-effects model and calculated the attenuation of excess risk after adjustment for mediators.

FINDINGS

The HR for each 5 kg/m(2) higher BMI was 1·27 (95% CI 1·23-1·31) for coronary heart disease and 1·18 (1·14-1·22) for stroke after adjustment for confounders. Additional adjustment for the three metabolic risk factors reduced the HRs to 1·15 (1·12-1·18) for coronary heart disease and 1·04 (1·01-1·08) for stroke, suggesting that 46% (95% CI 42-50) of the excess risk of BMI for coronary heart disease and 76% (65-91) for stroke is mediated by these factors. Blood pressure was the most important mediator, accounting for 31% (28-35) of the excess risk for coronary heart disease and 65% (56-75) for stroke. The percentage excess risks mediated by these three mediators did not differ significantly between Asian and western cohorts (North America, western Europe, Australia, and New Zealand). Both overweight (BMI ≥25 to <30 kg/m(2)) and obesity (BMI ≥30 kg/m(2)) were associated with a significantly increased risk of coronary heart disease and stroke, compared with normal weight (BMI ≥20 to <25 kg/m(2)), with 50% (44-58) of the excess risk of overweight and 44% (41-48) of the excess risk of obesity for coronary heart disease mediated by the selected three mediators. The percentages for stroke were 98% (69-155) for overweight and 69% (64-77) for obesity.

INTERPRETATION

Interventions that reduce high blood pressure, cholesterol, and glucose might address about half of excess risk of coronary heart disease and three-quarters of excess risk of stroke associated with high BMI. Maintenance of optimum bodyweight is needed for the full benefits.

FUNDING

US National Institute of Health, UK Medical Research Council, National Institute for Health Research Comprehensive Biomedical Research Centre at Imperial College Healthcare NHS Trust, Lown Scholars in Residence Program on cardiovascular disease prevention, and Harvard Global Health Institute Doctoral Research Grant.

Maladaptive immune and inflammatory pathways lead to cardiovascular insulin resistance

Insulin resistance is a hallmark of obesity, the cardiorenal metabolic syndrome and type 2 diabetes mellitus (T2DM). The progression of insulin resistance increases the risk for cardiovascular disease (CVD). The significance of insulin resistance is underscored by the alarming rise in the prevalence of obesity and its associated comorbidities in the Unites States and worldwide over the last 40-50 years. The incidence of obesity is also on the rise in adolescents. Furthermore, premenopausal women have lower CVD risk compared to men, but this protection is lost in the setting of obesity and insulin resistance. Although systemic and cardiovascular insulin resistance is associated with impaired insulin metabolic signaling and cardiovascular dysfunction, the mechanisms underlying insulin resistance and cardiovascular dysfunction remain poorly understood. Recent studies show that insulin resistance in obesity and diabetes is linked to a metabolic inflammatory response, a state of systemic and tissue specific chronic low grade inflammation. Evidence is also emerging that there is polarization of macrophages and lymphocytes towards a pro-inflammatory phenotype that contributes to progression of insulin resistance in obesity, cardiorenal metabolic syndrome and diabetes. In this review, we provide new insights into factors, such as, the renin-angiotensin-aldosterone system, sympathetic activation and incretin modulators (e.g., DPP-4) and immune responses that mediate this inflammatory state in obesity and other conditions characterized by insulin resistance.