Georg Egger

Body Iron Stores and the Risk of Carotid Atherosclerosis Prospective Results From the Bruneck Study

BACKGROUND Fe2+ released from tissue iron stores may accelerate lipid peroxidation by virtue of its pro-oxidant properties and thus promote early atherogenesis. METHODS AND RESULTS The present prospective survey addresses the potential association between serum ferritin concentrations and the 5-year progression of carotid atherosclerosis as assessed by ultrasonographic follow-up evaluations. The study population comprises a random sample of 826 men and women 40 to 79 years old. Serum ferritin was one of the strongest risk predictors of overall progression of atherosclerosis. The main part of this association appeared to act through modification of the atherogenic potential of LDL cholesterol (OR [95% CI] for a 1-SD unit increase in ferritin at LDL levels of 2.5, 3.6, and 4.9 mmol/L: 1.55 [1.30 to 1.85], 1.77 [1.40 to 2.24], and 2.05 [1.50 to 2.80]; P=.0012 for effect modification). Changes in iron stores during the follow-up period modified atherosclerosis risk, in that a lowering was beneficial and further iron accumulation exerted unfavorable effects. All these findings applied equally to incident atherosclerosis and the extension of preexisting atherosclerotic lesions. The significance of prominent iron stores in the development of carotid stenosis was clearly less pronounced. Finally, ferritin and LDL cholesterol showed a synergistic association with incident cardiovascular disease and death (n=59). CONCLUSIONS The present study provided strong epidemiological evidence for a role of iron stores in early atherogenesis and suggests promotion of lipid peroxidation as the main underlying pathomechanism. This hypothesis could in part explain the sex difference in atherosclerotic vascular disease.

Serum Soluble Heat Shock Protein 60 Is Elevated in Subjects With Atherosclerosis in a General Population

BACKGROUND Work from our laboratory has proven that increased titers of anti-heat shock protein 60 (HSP60) antibodies are associated with atherosclerosis and that HSP60-reactive T-cells are present in atherosclerotic lesions. Recent studies from others demonstrated that HSP60 directly activates endothelial cells and macrophages. METHODS AND RESULTS To explore the possibility that HSP60 exists in the circulation, where it could exert its functions, we performed a population-based study with 826 subjects aged 40 to 79 years. The following items were measured in all participants: serum soluble HSP60 (sHSP60); anti-Escherichia coli lipopolysaccharide; anti-HSP65, anti-Chlamydia and anti-Helicobacter pylori antibodies; and a variety of acute phase reactants (C-reactive protein, alpha(1)-antitrypsin, and ceruloplasmin) and markers of systemic inflammation. Carotid atherosclerosis was assessed twice (1990 and 1995), and 15 other risk factors were evaluated. Our data show that levels of sHSP60 were significantly elevated in subjects with prevalent/incident carotid atherosclerosis and that these levels were correlated with common carotid artery intima/media thickness. Multiple logistic regression analysis documented these associations as independent of age, sex, and other risk factors. Interestingly, sHSP60 was also correlated with anti-lipopolysaccharide, anti-Chlamydia and anti-HSP60 antibodies, various markers of inflammation, and the presence of chronic infections. The risk of atherosclerosis associated with high sHSP60 levels was amplified when subjects had clinical and/or laboratory evidence of chronic infections. CONCLUSIONS Our data provide the first evidence of a strong correlation between sHSP60 and atherosclerosis, suggesting that sHSP60 may play important roles in activating vascular cells and the immune system during the development of atherosclerosis.

Association of endotoxemia with carotid atherosclerosis and cardiovascular disease: prospective results from the Bruneck Study.

OBJECTIVES Focus of the current study was on the significance of bacterial endotoxin, which shows a variety of pro-atherogenic properties and may occur at high concentration in the circulation of infected subjects. BACKGROUND The possibility of an infectious risk factor in atherogenesis and cardiovascular disease has stimulated research interest, but the nature of such process remains obscure. METHODS We measured plasma endotoxin levels (LAL assay) in a random population of 516 men and women 50 to 79 years old at the 1990 baseline evaluation (Bruneck Study). End points of this prospective survey were incident (early) atherosclerosis in the carotid arteries as assessed with high-resolution Duplex ultrasound (five-year follow-up rate, 98%) and incident cardiovascular disease (follow-up rate, 100%). RESULTS Median endotoxin concentration amounted to 14.3 pg/ml (range, 6.0 to 209.2 pg/ml). Subjects with levels beyond 50 pg/ml (90th percentile) faced a threefold risk of incident atherosclerosis (odds ratio [95% confidence interval] 2.9 [1.4-6.3]; p < 0.01). The risk associated with high endotoxin was most pronounced in subjects with chronic infections and in current and ex-smokers. Notably, smokers with low endotoxin levels and nonsmokers did not differ in their atherosclerosis risk, whereas smokers with high levels almost invariably developed new lesions. All findings emerged as independent of vascular risk factors. Similar results were obtained for incident cardiovascular disease. CONCLUSIONS The current study yields first epidemiologic evidence that endotoxemia constitutes a strong risk factor of early atherogenesis in subjects with chronic or recurrent bacterial infections and a link in the association between cigarette smoking and atherosclerotic disease.

Chronic Infections and the Risk of Carotid Atherosclerosis

Background—Chronic infections have been implicated in the pathogenesis of atherosclerosis, yet from an epidemiological perspective, this concept remains controversial. Methods and Results—The Bruneck Study is a prospective population-based survey on the pathogenesis of atherosclerosis. In 826 men and women 40 to 79 years old (1990 baseline), 5-year changes in carotid atherosclerosis were thoroughly assessed by high-resolution duplex scanning. The presence of chronic respiratory, urinary tract, dental, and other infections was ascertained by standard diagnostic criteria. Chronic infections amplified the risk of atherosclerosis development in the carotid arteries. The association was most pronounced in subjects free of carotid atherosclerosis at baseline (age-/sex-adjusted odds ratio [95% CI] for any chronic infection versus none, 4.08 [2.42 to 6.85]; P<0.0001) and applied to all types of chronic (bacterial) infections. It remained independently significant after adjustment for classic vascular risk attribu...

Insulin sensitivity and regular alcohol consumption: large, prospective, cross sectional population study (Bruneck study)

Abstract Objectives: To assess the relation between regular alcohol consumption and insulin sensitivity, and to estimate the importance of insulin in the association of alcohol with multiple vascular risk factors and cardiovascular disease. Design: Prospective and cross sectional study of a large randomly selected population sample. Setting: Part of the Bruneck study 1990–5 (Bolzano province, Italy). Subjects: 820 healthy non-diabetic women and men aged 40–79 years. Main outcome measure: Concentrations of fasting and post-glucose insulin, cholesterol, apolipoproteins, triglycerides, Lp(a) lipoprotein, glucose, fibrinogen, and antithrombin III; blood pressure; insulin resistance estimated by the homeostasis model assessment. Results: Fasting insulin concentrations in those who did not drink alcohol and subjects reporting low (1–50 g/day), moderate (51–99 g/day), and heavy (>/=100 g/day) alcohol intake were 12.4, 10.0, 8.7, and 7.1 mU/l (P<0.001). Likewise, post-glucose insulin concentrations and estimates for insulin resistance assessed by the homeostasis model assessment decreased significantly with increasing amounts of regular alcohol consumption. These trends were independent of sex, body mass index, physical activity, cigarette smoking, medication, and diet (P<0.001). Regular alcohol intake predicted multiple changes in vascular risk factors over a five year period including increased concentrations of high density lipoprotein cholesterol and apolipoprotein A I; higher blood pressure; and decreased concentration of antithrombin III. These associations were in part attributable to the decrease in insulin concentrations observed among alcohol consumers. Conclusions: Low to moderate amounts of alcohol, when taken on a regular basis, improve insulin sensitivity. Insulin is a potential intermediate component in the association between alcohol consumption and vascular risk factors (metabolic syndrome). Key messages Regular alcohol consumption predicted multiple changes of vascular risk factors over a five year period This alcohol associated metabolic syndrome is in part attributable to the decline in insulin concentrations

Role of Lipoprotein(a) and Apolipoprotein(a) Phenotype in Atherogenesis Prospective Results From the Bruneck Study

BACKGROUND Experimental studies have suggested both atherogenic and thrombogenic properties of lipoprotein(a) [Lp(a)], depending on Lp(a) plasma concentrations and varying antifibrinolytic capacity of apolipoprotein(a) [apo(a)] isoforms. Epidemiological studies may contribute to assessment of the relevance of these findings in the general population. METHODS AND RESULTS This study prospectively investigated the association between Lp(a) plasma concentrations, apo(a) phenotypes, and the 5-year progression of carotid atherosclerosis assessed by high-resolution duplex ultrasound in a random sample population of 826 individuals. We differentiated early atherogenesis (incident nonstenotic atherosclerosis) from advanced (stenotic) stages in atherosclerosis that originate mainly from atherothrombotic mechanisms. Lp(a) plasma concentrations predicted the risk of early atherogenesis in a dose-dependent fashion, with this association being confined to subjects with LDL cholesterol levels above the population median (3.3 mmol/L). Apo(a) phenotypes were distributed similarly in subjects with and without early carotid atherosclerosis. In contrast, apo(a) phenotypes of low molecular weight emerged as one of the strongest risk predictors of advanced stenotic atherosclerosis, especially when associated with high Lp(a) plasma concentrations (odds ratio, 6.4; 95% CI, 2.8 to 14. 9). CONCLUSIONS Lp(a) is one of the few risk factors capable of promoting both early and advanced stages of atherogenesis. Lp(a) plasma concentrations predicted the risk of early atherogenesis synergistically with high LDL cholesterol. Low-molecular-weight apo(a) phenotypes with a putatively high antifibrinolytic capacity in turn emerged as one of the leading risk conditions of advanced stenotic stages of atherosclerosis.

Insulin resistance as estimated by homeostasis model assessment predicts incident symptomatic cardiovascular disease in caucasian subjects from the general population : The bruneck study

OBJECTIVE—The purpose of this study was to evaluate whether insulin resistance is associated to cardiovascular disease (CVD) and to understand whether this association can be explained by traditional and novel CVD risk factors associated with this metabolic disorder. RESEARCH DESIGN AND METHODS—We examined a sample representative of the population of Bruneck, Italy (n = 919; aged 40–79 years). Insulin-resistant subjects were those with a score in the top quartile of the homeostasis model assessment (HOMA) for insulin resistance (HOMA-IR). Risk factors correlated with insulin resistance included BMI, A1C, HDL cholesterol, triglycerides, blood pressure, high-sensitivity C-reactive protein (hsCRP), fibrinogen, oxidized LDL, vascular cell adhesion molecule-1 (VCAM-1), and adiponectin. Subjects without CVD at baseline were followed up for 15 years for incident CVD, a composite end point including fatal and nonfatal myocardial infarction and stroke, transient ischemic attack, and any revascularization procedure. RESULTS—During follow-up, 118 subjects experienced a first symptomatic CVD event. Levels of HOMA-IR were higher at baseline among subjects who developed CVD (2.8) compared with those remaining free of CVD (2.5) (P < 0.05). Levels of HOMA-IR also were significantly correlated (P < 0.05) with most CVD risk factors we evaluated. In Cox proportional hazard models, insulin-resistant subjects had an age-, sex-, and smoking-adjusted 2.1-fold increased risk (95% CI 1.3–3.1) of incident symptomatic CVD relative to non–insulin-resistant subjects. After sequential adjustment for physical activity and classic risk factors (A1C, LDL cholesterol, and hypertension) as well as BMI, HDL cholesterol, triglycerides, and novel risk factors, including fibrinogen, oxidized LDL, hsCRP, VCAM-1, and adiponectin, the association between HOMA-IR and incident CVD remained significant and virtually unchanged (hazard ratio 2.2 [95% CI 1.4–3.6], P < 0.001). CONCLUSIONS—HOMA-estimated insulin resistance is associated with subsequent symptomatic CVD in the general population independently of all classic and several nontraditional risk factors. These data suggest that insulin resistance may be an important target to reduce CVD risk.

Metabolic Syndrome: epidemiology and more extensive phenotypic description. Cross-sectional data from the Bruneck Study

OBJECTIVES: The present study aimed at evaluating the prevalence of the Metabolic Syndrome and at identifying its additional clinical features.RESEARCH DESIGN AND METHODS: Within a prospective population-based survey examining 888 subjects aged 40–79 y, subjects were identified fulfilling the WHO and the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) criteria for diagnosing the Metabolic Syndrome. In these subjects and in the rest of the sample (controls), several metabolic and nonmetabolic biochemical parameters were compared.RESULTS: The prevalence of the Metabolic Syndrome by WHO criteria was 34.1% (95% CI 31.0–37.2) and by NCEP-ATPIII criteria 17.8% (15.5–20.3). The prevalence was significantly higher in older subjects and in those less physically active. Subjects with the Metabolic Syndrome either by WHO or by NCEP-ATPIII criteria showed higher levels of oxidized low-density lipoprotein, apolipoprotein B, urate, leptin, fibrinogen, leukocytes, erythrocyte sedimentation rate, GOT, gamma-GT and soluble endothelial adhesion molecules (E-selectin, vascular adhesion molecule-1 and intercellular adhesion molecule-1) and lower apolipoprotein A concentrations. Insulin resistance, as assessed by the Homeostasis Model Assessment, increased with the increase in the number of traits composing the syndrome found within the single individual. Subjects with insulin resistance had more pronounced abnormalities in several parameters, including the additional features of the syndrome (eg fibrinogen and soluble adhesion molecules).CONCLUSIONS: The Metabolic Syndrome occurs very frequently in the general population aged 40–79 y, and is associated with several additional metabolic and nonmetabolic abnormalities that likely contribute to an increased cardiovascular risk. Insulin resistance seems to play a major role in classic and additional abnormalities featuring the Metabolic Syndrome.

Alcohol Consumption and Atherosclerosis: What Is the Relation? Prospective Results From the Bruneck Study

BACKGROUND AND PURPOSE Potential effects of regular alcohol consumption on atherogenesis are still controversial mainly due to the lack of prospective population-based studies. METHODS The Bruneck Study is a prospective population-based survey of atherosclerosis and its risk factors. The study population comprises a sex- and age-stratified random sample of men and women aged 40 to 79 years. Participation and follow-up were more than 90% complete. Changes in carotid atherosclerosis between the 1990 baseline and the first follow-up in 1995 were monitored by high-resolution duplex ultrasonography. Alcohol intake was quantified with a standardized questionnaire and prospective diet records. RESULTS Alcohol consumption less than once a week (occasional drinking) had no effect on atherogenesis. The association between regular alcohol intake and incident carotid atherosclerosis (early atherogenesis) was J-shaped, with light drinkers facing a lower risk than either heavy drinkers or abstainers. Protection offered by alcohol consumption of <50 g/d appeared to act through inhibition of the injurious action of high levels of low-density lipoprotein (LDL) cholesterol. Excess risk of incident atherosclerosis observed among heavy alcohol consumers (> or =100 g/d) clearly surpassed the risk burden afforded by heavy smoking. The association between regular alcohol intake and incident carotid stenosis (advanced atherogenesis) was U-shaped. Odds ratios were generally shifted toward protection and did not rely on LDL cholesterol levels. We failed to find any differential effects of alcohol from various sources. All associations remained independently significant when we adjusted for lifestyle, coincidental smoking, and the metabolic complex associated with drinking. CONCLUSIONS Our findings support the view that adverse and beneficial effects of alcohol on arterial disease are mediated in part by a dose-dependent promotion or deceleration of atherogenesis. The protection afforded by light drinking may possibly be attributed to antithrombotic effects and inhibition of the atherogenic action of high levels of LDL cholesterol.

Distinct Risk Profiles of Early and Advanced Atherosclerosis Prospective Results From the Bruneck Study

Most epidemiological surveys on risk factors of atherosclerosis were cross-sectional in design and did not consider the existence of pathologically distinct processes. The Bruneck Study is a prospective survey in the general community (age range, 40 to 79 years). The baseline examination and first reevaluation were performed in the summers of 1990 and 1995 (participation, 92%; follow-up, 96%). Carotid atherosclerosis was monitored with high-resolution duplex ultrasound. Early (incidence and/or extension of nonstenotic lesions) and advanced (incidence and/or progression of stenosis >40%) stages of atherogenesis were differentiated. The risk profile of early atherogenesis consists of traditional risk factors, such as hypertension, hyperlipidemia, and cigarette smoking (pack-years), supplemented by a variety of less well-established risk conditions, including high body iron stores, hypothyroidism, microalbuminuria, and high alcohol consumption. In contrast, the risk profile of advanced atherogenesis includes markers of enhanced prothrombotic capacity, attenuated fibrinolysis, and clinical conditions known to interfere with coagulation: high fibrinogen, low antithrombin, factor V Leiden mutation, lipoprotein(a) >0.32 g/L, high platelet count, cigarette smoking, and diabetes. Hyperlipidemia and hypertension were of only minor relevance. These findings, along with the epidemiological features of advanced atherogenesis and emergence of an elevated fibrin turnover, suggest atherothrombosis to be a key mechanism in the development of advanced stenotic atherosclerosis. Supplementary 6-category logistic regression models illustrate the changing association between major risk predictors and atherosclerosis of increasing severity and substantiate appropriateness of the 40% threshold applied for the definition of advanced stenotic atherosclerosis. Atherosclerosis is a heterogeneous process that subsumes etiologically and epidemiologically distinct disease entities. The multifactorial etiology of atherosclerosis, which goes far beyond the traditional risk factors, has not yet achieved adequate attention in clinical practice and disease prevention.