Intra-abdominal fat and metabolic syndrome are associated with larger infrarenal aortic diameters in patients with clinically evident arterial disease

Metabolic syndrome and the risk of abdominal aortic aneurysm: A nationwide cohort study

BACKGROUND AND AIMS

The association between metabolic syndrome (MetS) and abdominal aortic aneurysm (AAA) remains unclear. We investigated the potential association between AAA and MetS and its components in a large population-based cohort.

METHODS

We used the Korean National Health Insurance Service database including 4,162,640 participants aged ≥50 years who received a routine health examination in 2009. Cox proportional hazards models were used to analyze the association between MetS and its components (elevated waist circumference, blood pressure, glucose, triglycerides, and reduced high-density lipoprotein cholesterol [HDL-C]) with AAA incidence, with adjustment for confounders.

RESULTS

During a median 9.4 years of follow-up, 18,160 participants developed incident AAA. MetS was associated with an increased risk of AAA compared to the non-MetS group (adjusted hazard ratio [aHR], 1.38; 95% confidence interval [CI], 1.34-1.43). Among the individual components, elevated waist circumference, blood pressure, triglycerides, and reduced HDL-C were associated with increased AAA risk, while elevated glucose alone was associated with reduced AAA risk (aHR, 0.85; 95% CI, 0.82-0.87). AAA risk also increased linearly with the increasing number of MetS components, with the highest risk found in the presence of all 5 components (aHR, 1.98, 95% CI, 1.83-2.15).

CONCLUSIONS

MetS and its individual components, with the exclusion of elevated glucose, were associated with higher risk of AAA. Further studies are warranted to elucidate the association between MetS and AAA.

The neglected association between central obesity markers and abdominal aortic aneurysm presence: A systematic review and meta-analysis

Purpose

To review the association between central obesity and abdominal aortic aneurysm (AAA).

Materials and methods

The PubMed, Web of Sciences, Embase, The China national knowledge infrastructure (CNKI), and Cochrane Library were searched up to April 30, 2022. Researches includes investigation of the relationship between central obesity markers and AAA. Included studies must use recognized measures of central obesity, i.e., waist circumference (WC) and waist-to-hip ratio (WHR), or use imaging techniques to calculate abdominal fat distribution, such as computed tomography (CT) imaging.

Results

Eleven clinical researches were identified of which eight discussed the association between physical examination and AAA, and three studies mainly focused on abdominal fat volume (AFV). Seven researches concluded that there was a positive correlation between markers of central obesity and AAA. Three studies found no significant link between markers of central obesity and AAA. One of the remaining studies reported different results for each sex. Three studies pooled in a meta-analysis identified correlation between central obesity and AAA presence (RR = 1.29; 95% confidence interval, 1.14-1.46).

Conclusion

Central obesity plays a role in the risk of AAA. Standardized central obesity markers may be predictors of AAA. However, there was no association between abdominal fat volume and AAA. Additional relevant evidence and specific mechanisms warrant further study.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?IDCRD42022332519, identifier CRD42022332519.

Changes in aortic diameter induced by weight loss: The HELENA trial- whole-body MR imaging in a dietary intervention trial

Obesity-related metabolic disorders such as hypertension, hyperlipidemia and chronic inflammation have been associated with aortic dilatation and resulting in aortic aneurysms in many cases. Whether weight loss may reduce the risk of aortic dilatation is not clear. In this study, the diameter of the descending thoracic aorta, infrarenal abdominal aorta and aortic bifurcation of 144 overweight or obese non-smoking adults were measured by MR-imaging, at baseline, and 12 and 50 weeks after weight loss by calorie restriction. Changes in aortic diameter, anthropometric measures and body composition and metabolic markers were evaluated using linear mixed models. The association of the aortic diameters with the aforementioned clinical parameters was analyzed using Spearman`s correlation. Weight loss was associated with a reduction in the thoracic and abdominal aortic diameters 12 weeks after weight loss (predicted relative differences for Quartile 4: 2.5% ± 0.5 and -2.2% ± 0.8, p < 0.031; respectively). Furthermore, there was a nominal reduction in aortic diameters during the 50-weeks follow-up period. Aortic diameters were positively associated with weight, visceral adipose tissue, glucose, HbA1c and with both systolic and diastolic blood pressure. Weight loss induced by calorie restriction may reduce aortic diameters. Future studies are needed to investigate, whether the reduction of aortic diameters via calorie restriction may help to prevent aortic aneurysms.

Impact of obstructive sleep apnea on abdominal aortic diameters

Although obesity has been reported to be a potential risk factor for abdominal aortic dilatation, the impact of obstructive sleep apnea (OSA) on the abdominal aortic diameter remains unknown. We retrospectively reviewed 427 patients aged >45 years who underwent polysomnography and abdominal computed tomography from November 2008 to February 2012. Aortic diameters were measured at 3 locations: upper, infrarenal, and lower abdominal aorta. OSA was defined as non-OSA (apnea-hypopnea index [AHI] <10, n = 58), mild to moderate (AHI 10 to 30, n = 167), and severe (AHI ≥30, n = 202). Adjusted diameter was not significantly different among OSA severity categories at the upper (21.0, 21.3, and 21.4 mm, respectively) and infrarenal aorta (19.5, 20.2, and 19.9 mm, respectively) but was significantly different at the lower abdominal aorta (17.3, 18.2, and 18.2 mm, respectively, p = 0.006) with larger diameters in patients with OSA. Multivariate linear regression analyses revealed that risk profiles for aortic dilatation varied according to the location and gender and that OSA (AHI ≥10) was an independent risk factor for infrarenal and lower abdominal aortic dilatation only in men (β = 0.10 and 0.18, p = 0.049 and 0.001, respectively). In conclusion, OSA may enhance dilatation of the distal abdominal aorta in men.

Visceral adiposity is not associated with abdominal aortic aneurysm presence and growth

Previous studies in rodent models and patients suggest that visceral adipose could play a direct role in the development and progression of abdominal aortic aneurysm (AAA). This study aimed to assess the association of visceral adiposity with AAA presence and growth. This study was a case-control investigation of patients that did (n=196) and did not (n=181) have an AAA who presented to The Townsville Hospital vascular clinic between 2003 and 2012. Cases were patients with AAA (infra-renal aortic diameter >30 mm) and controls were patients with intermittent claudication but no AAA (infra-renal aortic diameter <30 mm). All patients underwent computed tomography angiography (CTA). The visceral to total abdominal adipose volume ratio was estimated from CTAs by assessing total and visceral adipose deposits using an imaging software program. Measurements were assessed for reproducibility by repeat assessments on 15 patients. AAA risk factors were recorded at entry. Forty-five cases underwent two CTAs more than 6 months apart to assess AAA expansion. The association of visceral adiposity with AAA presence and growth was examined using logistic regression. Visceral adipose assessment by CTA was highly reproducible (mean coefficient of variation 1.0%). AAA was positively associated with older age and negatively associated with diabetes. The visceral to total abdominal adipose volume ratio was not significantly associated with AAA after adjustment for other risk factors. Patients with a visceral to total abdominal adipose volume ratio in quartile four had a 1.63-fold increased risk of AAA but with wide confidence intervals (95% CI 0.71-3.70; p=0.248). Visceral adiposity was not associated with AAA growth. In conclusion, this study suggests that visceral adiposity is not specifically associated with AAA presence or growth although larger studies are required to confirm these findings.

Indicadores antropométricos na predição de síndrome metabólica em crianças e adolescentes: um estudo de base populacional

Objetivos: avaliar a capacidade dos indicadores antropométricos e pontos de corte na predição da síndrome metabólica (SM) em crianças e adolescentes. Métodos: estudo transversal, envolvendo amostra probabilística de 879 crianças e adolescentes de ambos os sexos. Dados metabólicos, antropométricos e sociodemográficos foram coletados. Para diagnóstico da SM, foi utilizada a definição modificada do National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III). A capacidade dos indicadores antropométricos na predição do SM foi avaliada por meio da curva Receiver Operating Characteristic (ROC). Resultados: a prevalência de SM foi de 6,6%. Na predição da SM, a área sob a curva ROC foi de 0,79 (0,72; 0,85) para índice de massa corporal (IMC), de 0,79 (0,73; 0,85) para circunferência da cintura (CC) e de 0,83 (0,78; 0,89) para circunferência da cintura corrigida pela estatura (RCE). O ponto de corte identificado para RCE na predição da SM foi de 0,448 (ambos os gêneros). Conclusões: todos os indicadores antropométricos utilizados, com pequena superioridade da RCE, foram bons preditores da SM. O ponto de corte identificado para RCE na predição da SM aproxima-se daquele proposto por alguns autores como universal. Sugere-se o uso deste índice dado a sua simples operacionalidade em estudos clínicos e epidemiológicos como preditor da SM.

Morphological and functional vascular changes induced by childhood obesity

BACKGROUND

To investigate endothelial dysfunction and morphological vascular changes in childhood obesity.

METHODS

93 overweight/obese children (body mass index 26 ± 5 kg/m(2); median 26 kg/m(2); interquartile range 22-28 kg/m(2)), mean age 10.9 ± 2.7 years, underwent a check-up of total, high-density lipoprotein- and low-density lipoprotein-cholesterol, triglycerides, C-reactive protein, erythrocyte sedimentation rate, and white blood cell count, together with ultrasound measures of flow-mediated dilatation, carotid intima-media thickness, and anterior-posterior diameter of the abdominal aorta.

RESULTS

The body mass index of overweight/obese children had a statistically significant linear relationship (p < 0.05) with triglycerides, erythrocyte sedimentation rate, carotid intima-media thickness, anterior-posterior diameter of the abdominal aorta, and flow-mediated dilatation values.

CONCLUSIONS

Overweight/obese children have an initial endothelial dysfunction and vascular damage, i.e., the first stage in the development of atherosclerosis.

Myocardial, perivascular, and epicardial fat

Myocardial fat content refers to the storage of triglyceride droplets within cardiomyocytes. In addition, the heart and arteries are surrounded by layers of adipose tissue, exerting vasocrine and paracrine control of the subtending tissues. The rapid development of the field of noninvasive imaging has made it possible to quantify ectopic fat masses and contents with an increasing degree of accuracy. Myocardial triglyceride stores are increased in obesity, impaired glucose tolerance, and type 2 diabetes. The role of intramyocardial triglyceride accumulation in the pathogenesis of left ventricular (LV) dysfunction remains unclear. Increased triglyceride content is associated with states of fatty acid overload to the heart, saturating the oxidative capacity. It may initially serve as a fatty acid sink to circumscribe the formation of toxic lipid species and subsequently foster cardiac damage. Epicardial and perivascular fat depots may exert a protective modulation of vascular function and energy partition in a healthy situation, but their expansion turns them into an adverse lipotoxic, prothrombotic, and proinflammatory organ. They are augmented in patients with metabolic disorders and coronary artery disease (CAD). However, the progressive association between the quantity of fat and disease severity in terms of extent of plaque calcification or noncalcified areas, markers of plaque vulnerability, and number of vessels involved is less confirmed. Functional or hybrid imaging may contribute to a better definition of disease severity and unveil the direct myocardial and vascular targets of adipose tissue action.

Perivascular adipose tissue as a cause of atherosclerosis

Perivascular adipose tissue surrounds (coronary) arteries and may be involved in local stimulation of atherosclerotic plaque formation. Epicardial adipose tissue, the adipose tissue within the pericardium, is a frequently used measure of coronary perivascular adipose tissue and can be quantified with echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI). The quantity of (coronary) perivascular adipose tissue is correlated with parameters of the metabolic syndrome, such as increased waist circumference, hypertriglyceridemia and hyperglycemia, and with coronary atherosclerosis. Coronary artery segments covered by myocardium are not exposed to coronary perivascular adipose tissue and interestingly, atherosclerosis is absent in these intra-myocardial segments. Pro-inflammatory cytokines and adipokines are expressed and secreted at a higher level in epicardial adipose tissue of patients with coronary artery disease compared to patients without coronary artery disease. Furthermore, in vitro and ex vivo perivascular adipose tissue induces inflammation of the artery wall by secretion of pro-inflammatory proteins. Atherogenesis in the vascular wall is thus stimulated from 'outside to inside'. Based on the results of clinical, ex vivo and in vitro studies, it can be argued that perivascular adipose tissue may be involved in the process of atherosclerosis.

Alcohol consumption and risk of recurrent cardiovascular events and mortality in patients with clinically manifest vascular disease and diabetes mellitus: the Second Manifestations of ARTerial (SMART) disease study

OBJECTIVE

This study investigated the relation between alcohol consumption and specific vascular events and mortality in a high risk population of patients with clinical manifestations of vascular disease and diabetes.

METHODS

Patients with clinically manifest vascular disease or diabetes (n=5447) from the SMART study were followed for cardiovascular events and mortality. Alcohol consumption was assessed with a baseline questionnaire and analysed in relation with coronary heart disease (CHD), amputations, stroke, and all-cause and vascular death.

RESULTS

After a follow up of 4.7 years, we documented 363 cases of CHD, 187 cases of stroke, 79 amputations and 641 cases of all-cause death, of which 382 were vascular. In multivariate-adjusted models, alcohol consumption was inversely associated with CHD (p(linear trend)=0.007) and stroke (p(linear trend)=0.051) with respective hazard ratios of 0.39 (95%CI: 0.20-0.76) and 0.67 (0.31-1.46) for consuming 10-20 drinks/week compared with abstainers. We observed significant U-shaped associations between alcohol consumption and amputations (p(quadratic trend)=0.001), all-cause death (p(quadratic trend)=0.001) and vascular death (p(quadratic trend)=0.013). Hazard ratios for consuming 10-20 drinks/week were 0.29 (0.07-1.30) for amputations, 0.40 (0.24-0.69) for all-cause death and 0.34 (0.16-0.71) for vascular death compared with abstainers. Similar associations were observed for red wine consumption only.

CONCLUSION

Moderate alcohol consumption (1-2 drinks/day) is not only associated with a reduced risk of vascular and all-cause death in a high risk patients with clinical manifestations of vascular disease, but also with reduced risks of non-fatal events like CHD, stroke and possibly amputations.

Relationship of heavy drinking, lipoprotein (a) and lipid profile to infrarenal aortic diameter

Abstract

The objective of this study was to examine the association of alcohol drinking and lipid profile with infrarenal aortic dimension. The diameter of the infrarenal aorta was measured using ultrasound in 395 individuals (mean 66.6 ± 10.3 years) with atherosclerotic diseases or risk factors. The associations between heavy drinking, serum lipoprotein (a) levels, lipid profile and infrarenal aorta diameters were examined. Heavy drinking and lipoprotein (a) were positively related with infrarenal aortic dimension, while low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C), LDL-C and total cholesterol (TC)/HDL-C were negatively associated with infrarenal aortic diameter ( p < 0.05). In addition, there were negative associations of LDL-C/HDL-C, TC/HDL-C and positive associations of HDL-C and apolipoprotein AI (Apo AI) with heavy drinking ( p < 0.05). In conclusion, there was a positive association between infrarenal aortic diameters and heavy drinking, as well as lipoprotein (a) levels. Furthermore, the novel and unexpected inverse association between LDL-C/HDL-C, LDL-C, TC/HDL-C and abdominal aortic diameter may suggest a possible role for anti-atherogenic lipid profile (characterized by a higher level of HDL-C and lower level of LDL-C) in aortic dilatation processes, which need to be clarified by further studies.

Anteroposterior diameter of the infrarenal abdominal aorta is higher in women with polycystic ovary syndrome

Background:

Women affected by polycystic ovary syndrome (PCOS) are known to be at higher risk of cardiovascular disease. The aim of this study was to identify the artery that first is affected by early pre-atherosclerotic changes in PCOS.

Methods:

Twenty-nine women with PCOS aged 17 to 27 years and 26 healthy nonhyperandrogenic volunteers with regular menses (control women) aged 16 to 28 years were enrolled. All PCOS patients were overweight or obese (body mass index [BMI] ≥ 25). Diagnosis of PCOS was performed in line with the 2003 Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group. Accordingly, PCOS was defined when at least two of the following three features were present after exclusion of other etiologies: 1) oligomenorrhea and or anovulation; 2) hyperandrogenism and/or hyperandrogenemia; and 3) polycystic ovaries visible at ultrasound. Androgen excess or related disorders were excluded. The intima-media thickness (IMT) of common carotid arteries and common femoral arteries and the anteroposterior diameter of the infrarenal abdominal aorta were measured by ultrasound. Lutenizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, total testosterone, androstenedione, and sex hormone-binding globulin (SHBG) serum levels were measured between the 3rd and the 6th day of spontaneous or progestin-induced menstrual cycle. Our study was performed in the absence of any medical treatment.

Results:

Women with PCOS showed a higher LH to FSH ratio (p < 0.01), increased fasting insulin (p < 0.001), total testosterone (p < 0.001), and androstenedione (p < 0.001) levels, and lower SHBG concentrations (p < 0.001) compared to control women. BMI and waist-to-hip ratio were also higher in women with PCOS (p < 0.000 and p < 0.001, respectively). Women with PCOS also showed increased total cholesterol (p < 0.001), triglyceride (p < 0.001), and apolipoprotein B (p < 0.001) levels. Vascular data showed women with PCOS had a higher anteroposterior diameter than control women (p < 0.005). However, when analysis of covariance was performed and BMI was entered into the model as a covariate, anteroposterior diameter did not maintain a significant association with PCOS.

Conclusion:

This study shows that anteroposterior diameter of the infrarenal abdominal aorta, but not IMT of common carotid arteries or common femoral arteries, is higher in women with PCOS than in women without this disease. This represents the earliest atherosclerotic change in women with PCOS. However, this alteration seems to be due to body weight secondary to PCOS and not due to PCOS per se.