Normal weight diabetic patients versus obese diabetics: relation of overall and abdominal adiposity to vascular health

Role of obesity related inflammation in pathogenesis of peripheral artery disease in patients of type 2 diabetes mellitus

Objective

Type 2 diabetes mellitus (T2DM) has emerged as one of the greatest global health challenges of twenty-first century. Visceral obesity is one of the most important determinant of insulin resistance (IR) as well as T2DM complications. Therefore this review focuses on the molecular mechanism of obesity induced inflammation, signaling pathways contributing to diabetes, as well as role of lifestyle interventions and medical therapies in the prevention and management of T2DM.

Method

Articles were searched on digital data base PubMed, Cochrane Library, and Web of Science. The key words used for search included Type 2 diabetes mellitus, obesity, insulin resistance, vascular inflammation and peripheral arterial disease.

Result

Visceral obesity is associated with chronic low grade inflammation and activation of immune systems which are involved in pathogenesis of obesity related IR and T2DM.

Conclusion

Metabolic dysregulation of adipose tissue leads to local hypoxia, misfolded/unfolded protein response and increased circulating free fatty acids, which in turn initiate inflammatory signaling cascades in the population of infiltrating cells. Mechanism that relates the role of adipocytokines with insulin sensitivity and glucose homeostasis might throw a light on the development of therapeutic interventions and subsequently might result in the reduction of vascular complications.

Association of triglyceride-glucose index with incident hypertension among non-overweight healthy adults: A cohort study in China

BACKGROUND AND AIMS

Overweight and obesity are well recognized as important and traditional risk factors for hypertension (HTN), but the prevalence of HTN tends to increase in non-overweight people. Triglyceride-glucose (TyG) index has been observed to be associated with HTN. However, whether such association still persists in non-overweight people remains unclear. The aim of our cohort study was to explore the link between TyG index and incident HTN in non-overweight Chinese population.

METHODS AND RESULTS

As many as 4678 individuals without HTN at baseline were involved, who underwent at least two years of health check-ups in the eight-year study period and maintained non-overweight at follow-up. According to baseline TyG index quintiles, participants were classified into five groups. Compared with the 1st quantile, those in the 5th quantile of TyG index had a 1.73-fold (HR 95% CI 1.13-2.65) risk of incident HTN. The results remained consistent when analyses were restricted to participants without abnormal TG or FPG level at baseline (HR 1.62, 95% CI 1.17-2.26). Furthermore, the subgroup analyses were conducted, the risk of incident HTN was still significantly increased with increasing TyG index for subgroups of older participants (age≥ 40 years), males, females and higher BMI group (BMI≥ 21 kg/m²).

CONCLUSIONS

The risk of incident HTN increased with increasing TyG index among Chinese non-overweight adults, so TyG index might be a reliable predictor of incident HTN among adults maintaining non-overweight.

Vascular dysfunction and body mass index in African adults with HIV

BACKGROUND

Impaired vascular compliance is common among persons with HIV (PWH) and a risk factor for cardiovascular disease (CVD), though many studies documenting this are from regions with a high prevalence of overweight and obesity. The prevalence and characteristics of impaired vascular compliance among PWH with low body mass index (BMI) is not well described, particularly in sub-Saharan Africa (SSA) where the majority of PWH live, a low BMI is more common, and the burden of CVD is rising.

AIM

To assess non-invasive vascular compliance measurements, including augmentation index (AIX), pulse wave velocity (PWV) and pulse waveforms, in underweight, normal weight, and overweight PWH on long-term antiretroviral therapy (ART) in SSA.

METHODS

A cross-sectional study among PWH on ART at the University Teaching Hospital in Lusaka, Zambia. All participants had been on a regimen of efavirenz, emtricitabine, and tenofovir disoproxil fumarate for five or more years. Carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and the corresponding augmentation indexes (cfAIX and crAIX), were measured in all participants, in addition to aortic pressure waveforms, classified as type A, B, C and D according to reflected wave timings and amplitude. Multiple linear regression assessed relationships between demographic and clinical factors with vascular measurement endpoints.

RESULTS

Ninety one PWH on long-term ART were enrolled; 38 (42%) were underweight (BMI < 18.5 kg/m²), 43 (47%) were normal weight (18.5-24.9 kg/m²) and 10 (11%) were overweight (> 25 kg/m²). Median age was 41, 40 and 40 years, among the three groups, respectively, and the proportion of women increased with BMI level. Overweight participants had a 39% higher cfAIX compared to normal-weight participants, while being underweight was associated with 27% lower cfAIX, after adjusting for age, sex and blood pressure (P = 0.02 and P = 0.01, respectively), but measurements of cfPWV, crPWV and crAIX did not differ.

CONCLUSION

Underweight PWH in SSA had lower cfAIX measurements compared to normal weight individuals, indicating less arterial stiffness. However, similar cfPWV, crPWV and crAIX values among the underweight and overweight PWH suggest a low BMI may not confer substantial protection against impaired vascular compliance as a contributor to CVD risk among individuals on ART.

Normative reference data for body composition in healthy indigenous populations on the Qinghai-Tibet Plateau

Body composition represents an important aspect of physical fitness and has received increasing attention in recent years. The present study was designed and conducted to provide reference values for age-, sex-, and altitude-specific body composition for healthy indigenous Tibetan adults living on the Qinghai-Tibet Plateau, which has not yet been studied. A cross-sectional survey was conducted among 2,356 healthy Tibetan adults (1,433 females and 923 males) living on the Qinghai-Tibet Plateau for generations. The body composition of the participants was measured by bioelectrical impedance analysis (BIA). The measurements included weight, basal metabolic rate (BMR), fat-free mass (FFM), skeletal muscle mass (SMM), protein mass (PM), bone mass (BM), fat mass (FM), percentage of body fat (PBF), subcutaneous fat mass (SFM), visceral fat mass (VFM), total body water (TBW), intracellular water (ICW), and extracellular water (ECW). Overall, males had greater FFM, SMM, PM, BM, and water mass, whereas females were high in fat mass. Participants from plains generally had higher body composition values, and PM, BM, FM and body water values decreased with increasing altitude, with the lowest values found in >4,000 m Shigatse. FFM, SMM, PM, and BM tended to decrease with increasing age, whereas fat mass and ECW tended to increase with increasing age. This study provides the first normative reference data of body composition for healthy indigenous individuals on the Qinghai-Tibet Plateau. These datasets are important for future research related to body composition. A considerable decrease in body composition values in > 4,000 m-altitude areas suggested that body composition cutoff values should be established by altitude. Age-, sex-, and altitude-specific alterations in body composition values also inform the prevention and amendment of abnormal body composition changes and resultant health complications.

Immune activation and arterial stiffness in lean adults with HIV on antiretroviral therapy

Background

Greater T-cell activation was associated with reduced vascular compliance amongst persons living with HIV (PLWH) especially among overweight and obese individuals. There is a paucity of data regarding immune activation and arterial stiffness amongst PLWH in sub-Saharan Africa (SSA).

Objective

To determine the association between immune activation and arterial stiffness in lean PLWH in SSA.

Method

Forty-eight human immunodeficiency virus positive (HIV+) adults on antiretroviral therapy (ART) >5 years and 26 HIV-negative adults, all with BMI < 25 kg/m² and no history of CVD, were enrolled. The relationship of vascular compliance with circulating CD4+ and CD8+ naïve, memory, activated and senescent T cells, and serum 8-isoprostane was assessed by HIV status.

Results

Increased immune activation was observed in the CD4+ and CD8+ T cells of PLWH, 16.7% vs. 8.9% and 22.0% vs. 12.4% respectively; p < 0.001 (both). Furthermore, a higher proportion of senescent CD4+ T cells were associated with a lower carotid-femoral pulse wave velocity (cfPWV; p = 0.01), whilst a higher proportion of activated CD8+ T cells were associated with a lower carotid-radial pulse wave velocity (crPWV; p = 0.04), after adjustment for BMI and age. However, PLWH also had a higher median carotid-femoral augmentation index (cfAiX) (21.1% vs. 6.0%; p < 0.05) in comparison to their HIV controls.

Conclusion

Our population of lean PLWH had increased immune activation and higher cfAiX, a marker of arterial stiffness, compared to HIV-negative persons. The negative association between immune activation and arterial stiffness as measured by crPWV in PLHW on long-term treatment needs further elucidation.

Association between inflammatory obesity phenotypes, FTO-rs9939609, and cardiovascular risk factors in patients with type 2 diabetes

Background

The role of inflammatory states in cardiometabolic risks among patients with type 2 diabetes mellitus (T2DM) with similar degrees of obesity is unknown. The study aimed to compare cardiometabolic risk factors in inflammatory obesity phenotypes with regard to the role of the FTO rs9939609 gene polymorphism.

Materials and Methods

This study was performed on 155 patients with T2DM (77 men and 78 women) in Ahvaz, Iran. Participants were grouped into four groups based on the presence of obesity and inflammation (high-sensitivity C-reactive protein ≥3.9 mg/L): low inflammatory normal weight (LINW), high inflammatory normal weight (HINW), low inflammatory obese (LIO), and high inflammatory obese (HIO). The genotypes of FTO rs9939609, including homozygous carriers of the FTO risk allele (AA), heterozygous carriers (AT), and carrying no risk allele (TT), were studied. The cardiometabolic risk factors, including anthropometric status, hypertension, lipid and glycemic profile, and inflammatory markers, were evaluated. The waist-hip ratio (WHR), mean arterial pressure (MAP), and atherogenic index of plasma (AIP) were calculated.

Results

The patients in inflammatory groups (HINW and HIO) have significantly higher levels in AIP when compared to inflammatory healthy groups (LINW and LIO). No significant differences between any of the four group means were detected in WHR, blood pressure, MAP, glycemic status (fasting blood sugar and insulin), homeostatic model assessment, lipid profile (triglyceride, very low-density lipoprotein, high-density lipoprotein, low-density lipoprotein, and cholesterol), interleukin-6, and total antioxidant capacity. The most frequent of high-risk genotype (AA) of FTO rs9939609 was in HIO, LIO, HINW, and LINW.

Conclusion

T2DM patients with inflammatory condition have similar degree of increased atherogenic risk irrespective of obesity. The obesity-risk genotype AA of FTO gene was associated with an increased risk for inflammatory obesity in T2DM patients.

Age- and sex-related differences in body composition in healthy subjects aged 18 to 82 years

Significant changes in body composition are known to occur with aging. The aim of the present study was to provide a normative reference of body composition and to investigate age and sex-related differences in healthy subjects by multifrequency bioelectrical impedance analyzer (BIA).A cross-sectional study was conducted on a sample of 3451 healthy Chinese adults, 1611 males and 1840 females. The volunteers were enrolled in 5 different age bands (18-30, 31-40, 41-50, 51-60, 60+). All subjects were measured for weight and height and submitted to BIA, to determine body composition. Body composition measures accounted for differences between men and women.A decrease in fat-free mass and increase in percent body fat was observed with aging, although the phenomenon was proved to be attenuated in women. The central and visceral redistribution of fat mass was also shown along lifetime.This study is a report on body composition of healthy subjects, to be used as an important data for future investigations and differences between nationalities and countries.

Periodontitis is associated with diabetic retinopathy in non-obese adults

PURPOSE

Patients with diabetes retinopathy appear to show increased susceptibility to periodontal disease. This study was performed to assess the relationship between periodontitis and the prevalence of diabetic retinopathy in a large probability sample of the Korean population. A subgroup analysis was performed using body mass index <25 kg/m² as the criterion to evaluate the effect of obesity on this relationship.

METHODS

This study is based on data from the Korean National Health and Nutrition Examination Survey of the Korean population, conducted between 2008 and 2010. The presence of diabetic retinopathy in relation to demographic variables and anthropometric characteristics of the participants is presented as means with their standard errors. The presence of periodontitis and presence of retinopathy categorized by body mass index (<25 and ≥25 kg/m²) were evaluated. Multiple logistic regression analyses were used to assess the associations between periodontitis and diabetic retinopathy after adjustment with variables, including age, sex, smoking, drinking, exercise, hypertension, metabolic syndrome, HbA1c, and duration of diabetes mellitus.

RESULTS

There was a statistically significant increase in the prevalence of periodontitis in individuals who had proliferative diabetic retinopathy. The odds ratios [95% confidence intervals] of prevalence of diabetic retinopathy were 1.193 [0.757-1.881] for the whole population after adjustments with confounding factors. Subgroup analysis after adjustments with confounding factors showed that the odds ratios [95% confidence intervals] of prevalence were 2.206 [1.114-4.366] and 0.588 [0.326-1.061] among participants with body mass index <25 kg/m² and body mass index 37 ≥25 kg/m², respectively.

CONCLUSIONS

The diabetic retinopathy was positively associated with the presence of periodontitis in non-obese diabetic Korean adults after adjustment with confounding variables. Our findings suggest that when a periodontist finds the presence of periodontitis in non-obese diabetic patients, timely evaluation of the patient's ophthalmic evaluation should be 44 recommended.

Prevalence of Prediabetes and Abdominal Obesity Among Healthy-Weight Adults: 18-Year Trend

PURPOSE

Trends in sedentary lifestyle may have influenced adult body composition and metabolic health among individuals at presumably healthy weights. This study examines the nationally representative prevalence of prediabetes and abdominal obesity among healthy-weight adults in 1988 through 2012.

METHODS

We analyzed the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES for the years 1999 to 2012, focusing on adults aged 20 years and older who have a body mass index (BMI) of 18.5 to 24.99 and do not have diabetes, either diagnosed or undiagnosed. We defined prediabetes using glycated hemoglobin (HbA1c) level ranges from 5.7% to 6.4%, as specified by the American Diabetes Association. Abdominal obesity was measured by waist circumference and waist-to-height ratio.

RESULTS

The prevalence of prediabetes among healthy-weight adults, aged 20 years and older and without diagnosed or undiagnosed diabetes, increased from 10.2% in 1988-1994 to 18.5% in 2012. Among individuals aged 45 years and older, the prevalence of prediabetes increased from 22.0% to 33.1%. The percentage of adults aged 20 years and older with an unhealthy waist circumference increased from 5.6% in 1988-1994 to 7.6% in 2012. The percentage of individuals with an unhealthy waist-to-height ratio increased from 27.2% in 1988-1994 to 33.7% in 2012. Adjusted models found that measures of abdominal obesity were not independent predictors of prediabetes among adults with a healthy BMI.

CONCLUSIONS

Among individuals within a healthy BMI range, the prevalence of prediabetes and abdominal obesity has substantially increased. Abdominal obesity does not appear to be the primary cause of the increase.

Sensitivity of various adiposity indices in identifying cardiometabolic diseases in Arab adults

Background

Obesity is a recognized risk factor for various cardiometabolic diseases and several indices are used clinically to assess overall cardiometabolic risk. This study aims to determine the sensitivity of six anthropometric indices [Body mass index (BMI), waist, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body adiposity index (BAI) and visceral adiposity index (VAI)] in determining diabetes mellitus type 2, coronary heart disease, dyslipidemia, hypertension and metabolic syndrome (MetS) in Saudi adults recruited from two independent cohorts (2008–2009 and 2013–2014).

Methods

A total of 6,821 Saudi adults [2008–2009, N = 3,971 (1,698 males and 2,273 females); 2013–2014, N = 2,850 (926 males and 1,924 females)] aged 18–70 years old were included in this descriptive, cross-sectional study. Anthropometrics were obtained and fasting blood samples analyzed for glucose and lipids. BMI, WHR, WHtR, BAI and VAI were computed mathematically.

Results

VAI was the most sensitive index in determining DMT2 (AUC 0.72; p < 0.001) in the 2008–2009 cohort and MetS (AUC = 0.84; p < 0.001) in the 2013–2014 cohort. WHR was most discriminating for CHD in both cohorts (AUC 0.70 and 0.84 for 2008–2009 and 2013–2014, p values <0.001, respectively). WHtR was most sensitive but rather modest in determining hypertension (AUC 0.66; p < 0.001), while waist circumference was most sensitive for dyslipidemia (AUC 0.72; p < 0.001) in the 2008–2009 cohort and MetS (AUC 0.85; p < 0.001) in the 2013–2014 cohort. BAI was the least sensitive adiposity index.

Conclusion

Sensitivity of adiposity indices regarding cardiometabolic diseases highlight the importance of body fat distribution in determining overall cardiometabolic risk, with indices involving abdominal obesity being more clinically significant than BMI and BAI. The sensitivity of these adiposity indices should be noted in assessing a particular cardiometabolic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0265-5) contains supplementary material, which is available to authorized users.

Serum fibroblast growth factor 21 levels are related to subclinical atherosclerosis in patients with type 2 diabetes

BACKGROUND

Fibroblast growth factor 21 (FGF21), a glucose and lipid metabolic regulator, has recently been demonstrated to be associated with cardiovascular diseases (CVD) such as carotid atherosclerosis, coronary heart disease and carotid artery plaques. However, the relationship between circulating FGF21 and subclinical atherosclerosis or atherosclerosis of other arteries such as the femoral and iliac artery remains unclear. In this study, we evaluated the association of serum FGF21 with intima-media thickness (IMT) and subclinical atherosclerosis in type 2 diabetic patients.

METHODS

Serum FGF21 levels were detected by enzyme-linked immunosorbent assay in 212 newly diagnosed type 2 diabetic patients without clinical symptoms of atherosclerosis or cardiovascular diseases. IMT of the carotid, femoral, and iliac arteries were measured by high-resolution B-mode ultrasound to determine the presence of subclinical atherosclerosis, which was defined as having an IMT > 1.0 mm and/or plaque on one or more of the three arteries without any clinical manifestations. The relationship between serum FGF21 levels and subclinical atherosclerosis was analyzed.

RESULTS

Serum FGF21 levels were significantly higher in patients with subclinical atherosclerosis compared to those without [261.3 (135.1-396.4) versus 144.9 (95.9-223.0) ng/L, P < 0.001]. These differences were also observed in both men and women with subclinical atherosclerosis compared to their respective groups without [men: 243.2 (107.6-337.0) versus 136.8 (83.6-212.8) ng/L, P = 0.048; women: 292.4 (174.2-419.9) versus 160.4 (115.3-258.5) ng/L, P = 0.001]. Moreover, serum FGF21 levels showed a significantly positive correlation with carotid IMT in women (r = 0.23, P = 0.018) and with iliac IMT in both genders (women: r = 0.27, P = 0.005; men: r = 0.22, P = 0.024). Multiple logistic regression analysis further showed that serum FGF21 was an independent impact factor for subclinical atherosclerosis in patients with type 2 diabetes.

CONCLUSIONS

Serum FGF21 is elevated in newly diagnosed type 2 diabetes, and positively correlates with carotid and iliac lesions in patients with subclinical atherosclerosis, especially in women. High levels of FGF21 may be a compensatory reaction to offset atherosclerosis.

Serum leptin levels are independently related to the incidence of ischemic heart disease in a prospective study of patients with type 2 diabetes

Background

New and clinically useful markers of cardiovascular risk are of essence in type 2 diabetes since ischemic heart disease is a major cause of death in these patients.

Methods

We analyzed baseline data from 476 men and 244 women who participated in “Cardiovascular Risk factors in Patients with Diabetes -a Prospective study in Primary care” study. All participants had type 2 diabetes and were 55-66 years old at recruitment during year 2005 to 2008. Except for established traditional risk markers for vascular disease, we also estimated vascular complications non-invasively by performance of carotid-femoral pulse-wave velocity (PWV, with applanation-tonometry) and intima-media thickness of carotid arteries (IMT, with B-mode ultrasound). Patients were followed for incidence of ischemic heart disease mortality and morbidity until end of the year 2012, using the national Swedish Cause of Death and Hospitalization Registries.

Results

During the follow-up period of a median of 6 years 47 men and 10 women died or were hospitalized for ischemic heart disease including myocardial infarction. Leptin levels were positively related to the hazard ratio (HR) in men (HR for each log 10 unit 4.9, CI 1.99 to 11.8) and women (HR 11.5, CI 1.47 to 89.7). Leptin predicted ischemic heart disease independently of age, HbA1c, BMI, systolic blood pressure and LDL-cholesterol/HDL-cholesterol ratio (men: HR 12.9 CI 3.2-53, women: HR 19.9, CI 1.2-327) This finding of increased risk related to high leptin levels was also statistically significant when carotid-femoral PWV and IMT were both added to the equations in men (hazard ratio 9.2 CI 2.1-41).

Conclusions

Our data support the use of serum leptin in type 2 diabetes to add independent prognostic information in terms of ischemic heart disease when compared with traditional cardiovascular risk factors. In the men of the cohort this prognostic information was in addition also to data on IMT and PWV, two non-invasive measurements of the extent of vascular disease. The power to detect a similar relationship in women was less strong due to lower incidence of cardiovascular disease.

Trial registration

ClinicalTrials.gov: NCT01049737.

Normal-weight obesity is associated with increased risk of subclinical atherosclerosis

BACKGROUND

Subjects with normal body mass index (BMI) but elevated amounts of body fat (normal-weight obesity; NWO) show cardiometabolic dysregulation compared to subjects with normal BMI and normal amounts of body fat (normal-weight lean; NWL). In this study, we aimed to evaluate whether NWO individuals have higher rates of subclinical atherosclerosis compared to NWL subjects.

METHODS

From a large-scale health checkup system, we identified 2078 normal weight (18.5 ≤ BMI < 25 kg/m(2)) subjects with no previous history of coronary artery disease who underwent analysis of atherosclerosis using coronary computed tomography angiography (CCTA) and pulse wave velocity (PWV). NWO was defined as normal BMI and highest tertile of body fat percentage by sex (men ≥ 25. 4 % and women ≥ 31.4 %). CCTA was performed using a 64-detector row CT. A plaque was defined as a structure >1 mm(2) within and/or adjacent to the vessel lumen and classified according to the presence/proportion of intraplaque calcification.

RESULTS

NWO subjects (n = 283) demonstrated metabolic dysregulation compared to NWL individuals (n = 1795). After adjusting for age, sex, and smoking, NWO individuals showed higher PWV values than NWL individuals (1474.0 ± 275.4 vs. 1380.7 ± 234.3 cm/s, p = 0.006 by ANCOVA). Compared with NWL subjects, NWO subjects had a higher prevalence of soft plaques even after age, sex, and smoking adjustment (21.6% vs. 14.5%, p = 0.039 by ANCOVA). The PWV value and the log{(number of segments with plaque) + 1} showed a positive correlation with numerous parameters such as age, systolic blood pressure, visceral fat, fasting glucose level, serum triglyceride level, and C-reactive protein (CRP) in contrast to the negative correlation with high-density lipoprotein-cholesterol level. The visceral fat was an independent determinant of log{(number of segments with plaque) + 1} (ß = 0.027, SE = 0.011, p = 0.016) even after adjustment for other significant factors. Most importantly, NWO was an independent risk factor for the presence of soft plaques (odds ratio 1.460, 95 % confidence interval 1.027-2.074, p = 0.035) even after further adjustment for multiple factors associated with atherosclerosis (blood pressure, blood glucose, lipid level, CRP, medication, smoking status, physical activity).

CONCLUSIONS

NWO individuals carry a higher incidence of subclinical atherosclerosis compared with NWL individuals, regardless of other clinical risk factors for atherosclerosis.

Association of obesity with glucose, blood pressure, and lipid goals attainment in patients with concomitant diabetes and hypertension

OBJECTIVE

To investigate the associations between obesity and any significant improvements in glycemic control, blood pressure, and lipid targets in Chinese patients with concomitant type 2 diabetes mellitus (T2DM) and hypertension.

METHODS AND RESULTS

A total of 3041 dyslipidemia patients with an average age of 65.7 ± 10.53 years and comorbid conditions of T2DM and hypertension from the DYSlipidemia International Study (DYSIS) - China were included in the present subgroup analysis. Patients' demographic data, medication use, blood glucose, and lipid parameters were analyzed retrospectively. Body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WtHR) differed significantly among participants according to the attainment of treatment targets. Among female patients, significant differences in the rate of target attainment were observed among different WC, WtHR, and BMI quartile groups, whereas no significant differences in goal attainment were found according to WC and WtHR quartiles in male patients. Among the female patients, the results of logistic regression supported a significant association of anthropometric indices and the achievement of targets.

CONCLUSION

A considerable proportion of dyslipidemia patients failed to achieve guideline-recommended targets in China, and this apparent treatment gap was more pronounced among women with central adiposity and patients with an elevated BMI. Based on the limitations of this cross-sectional study, further investigation of the mechanism at the molecular level is necessary.