Carotid intima-media thickness, cardiovascular risk factors and albuminuria in a remote Australian Aboriginal community

Background: Rates of cardiovascular disease and renal disease in Australian Aboriginal communities are high, as is the prevalence of some 'traditional' cardiovascular (CV) risk factors, such as diabetes and cigarette smoking. Recent work has highlighted the importance of markers of inflammation, such as C-reactive protein (CRP), homocysteine and albuminuria as predictors of cardiovascular risk in urban westernised settings. It is not clear how these factors relate to outcome in the setting of these remote communities, but very high CRP concentrations have been shown in this and other Aboriginal communities. Methods and results: In a cross-sectional survey including 237 adults in a remote Aboriginal community in the Northern Territory of Australia, we measured carotid intima-media thickness (IMT), together with blood pressure, diabetes, lipid levels, smoking and albuminuria, CRP and fibrinogen, serum homocysteine concentration, and IgG titres for Chlamydia pneumoniae, Helicobacter pylori and cytomegalovirus. Median carotid IMT was 0.63 [interquartile range 0.54-0.71] mm. As a categorical outcome, the prevalence of the highest IMT quartile ('increased IMT', greater than or equal to0.72 mm) was compared with the lower three quartiles. Increased IMT was associated in univariate analyses with greater waist circumference, systolic BP, fibrinogen and serum albumin concentrations, urine albumin/creatinine ratio and older age as continuous variables. Associations of increased IMT with some continuous variables were not linear; univariate associations were seen with the highest quartile (versus all other quartiles) of CRP and homocysteine concentration and CMV IgG titre. In a multivariate model age, smoking, waist circumference and the highest quartile of CRP concentrations (greater than or equal to14 mg/l) remained significant predictors of IMT greater than or equal to0.72 mm. Conclusions: Measurement of carotid IMT was possible in this remote setting. Increased IMT (greater than or equal to0.72 mm) was associated with increased CRP concentrations over a range that suggests infection/inflammation may be important determinants of cardiovascular risk in this setting. The associations of IMT with markers of renal disease seen in univariate analyses were explained in this analysis by confounding due to the associations of urine ACR with other risk factors. (C) 2004 Published by Elsevier Ireland Ltd.

Carotid artery intimal medial thickness, brachial artery flow-mediated vasodilation and cardiovascular risk factors in diabetic and non-diabetic indigenous Australians

Background: Indigenous Australians are at high risk for cardiovascular disease and type 2 diabetes. Carotid artery intimal medial thickness (CIMT) and brachial artery flow-mediated vasodilation (FMD) are ultrasound imaging based surrogate markers of cardiovascular risk. This study examines the relative contributions of traditional cardiovascular risk factors on CIMT and FMD in adult Indigenous Australians with and without type 2 diabetes mellitus. Method: One hundred and nineteen Indigenous Australians were recruited. Physical and biochemical markers of cardiovascular risk, together with CIMT and FMD were meausred for all subjects. Results: Fifty-three Indigenous Australians subjects (45%) had type 2 diabetes mellitus. There was a significantly greater mean CIMT in diabetic versus non-diabetic subjects (p = 0.049). In the non-diabetic group with non-parametric analyses, there were significant correlations between CIMT and: age (r = 0.64, p < 0.001), systolic blood pressure (r = 0.47, p < 0.001) and non-smokers (r = -0.30, p = 0.018). In the diabetic group, non-parametric analysis showed correlations between CIMT, age (r = 0.36, p = 0.009) and duration of diabetes (r = 0.30, p = 0.035) only. Adjusting forage, sex, smoking and history of cardiovascular disease, Hb(A1c) became the sole significant correlate of CIMT (r = 0.35,p = 0.01) in the diabetic group. In non-parametric analysis, age was the sole significant correlate of FMD (r = -0.31,p = 0.013), and only in non-diabetic subjects. Linear regression analysis showed significant associations between CIMT and age (t = 4.6,p < 0.001), systolic blood pressure (t = 2.6, p = 0.010) and Hb(A1c) (t = 2.6, p = 0.012), smoking (t = 2.1, p = 0.04) and fasting LDL-cholesterol (t = 2.1, p = 0.04). There were no significant associations between FMD and examined cardiovascular risk factors with linear regression analysis Conclusions: CIMT appears to be a useful surrogate marker of cardiovascular risk in this sample of Indigenous Australian subjects, correlating better than FMD with established cardiovascular risk factors. A lifestyle intervention programme may alleviate the burden of cardiovascular disease in Indigenous Australians by reducing central obesity, lowering blood pressure, correcting dyslipidaemia and improving glycaemic control. CIMT may prove to be a useful tool to assess efficacy of such an intervention programme. (c) 2004 Elsevier Ireland Ltd. All rights reserved.

Socioeconomic position, cognitive function, and clustering of cardiovascular risk factors in adolescence: Findings from the Mater University Study of Pregnancy and its outcomes

Objectives: The objectives of this study were to examine the extent of clustering of smoking, high levels of television watching, overweight, and high blood pressure among adolescents and whether this clustering varies by socioeconomic position and Cognitive function. Methods: This study was a cross-sectional analysis of 3613 (1742 females) participants of an Australian birth cohort who were examined at age 14. Results: Three hundred fifty-three (9.8%) of the participants had co-occurrence of three or four risk factors. Risk factors clustered in these adolescents with a greater number of participants than would be predicted by assumptions of independence having no risk factors and three or four risk factors. The extent of clustering tended to be greater in those from lower-income families and among those with lower cognitive function. The age-adjusted ratio of observed to expected cooccurrence of three or four risk factors was 2.70 (95% confidence interval [Cl], 1.80-4.06) among those from low-income families and 1.70 (95% Cl, 1.34-2.16) among those from more affluent families. The ratio among those with low Raven's scores (nonverbal reasoning) was 2.36 (95% Cl, 1.69-3.30) and among those with higher scores was 1.51 (95% Cl, 1.19-1.92); similar results for the WRAT 3 score (reading ability) were 2.69 (95% Cl, 1.85-3.94) and 1.68 (95% Cl, 1.34-2.11). Clustering did not differ by sex. Conclusion: Among adolescents, coronary heart disease risk factors cluster, and there is some evidence that this clustering is greater among those from families with low income and those who have lower cognitive function.

A comparison of the association between socioeconomic position and cardiovascular disease risk factors in three age cohorts of Australian women: findings from the Australian Longitudinal Study on Women's Health

Objectives To assess the associations between three measurements of socioeconomic position (SEP) - education, occupation and ability to cope on available income - and cardiovascular risk factors in three age cohorts of Australian women. Methods Cross-sectional analysis of three cohorts of Australian women aged 18-23, 45-50 and 70-75 years. Results In general, for all exposures and in all three cohorts, the odds of each adverse risk factor (smoking, obesity and physical inactivity) were lower in the most advantaged compared with the least advantaged. Within each of the three cohorts, the effects of each measurement of SEP on the outcomes were similar. There were, however, some notable between-cohort differences. The most marked differences were those with smoking. For women aged 70-75 (older), those with the highest educational attainment were more likely to have ever smoked than those with the lowest level of attainment. However, for the other two cohorts, this association was reversed, with a stronger association between low levels of education and ever smoking among those aged 18-23 (younger) than those aged 45-50 (mid-age). Similarly, for older women, those in the most skilled occupational classes were most likely to have ever smoked, with opposite findings for mid-age women. Education was also differently associated with physical inactivity across the three cohorts. Older women who were most educated were least likely to be physically inactive, whereas among the younger and mid-age cohorts there was little or no effect of education on physical inactivity. Conclusion These findings demonstrate the dynamic nature of the association between SEP and some health outcomes. Our findings do not appear to confirm previous suggestions that prestige-based measurements of SEP are more strongly associated with health-related behaviours than measurements that reflect material and psychosocial resources.

C-reactive protein, cardiovascular risk, and renal disease in a remote Australian Aboriginal community

Rates of cardiovascular and renal disease in Australian Aboriginal communities are high, but we do not know the contribution of inflammation to these diseases in this setting. In the present study, we sought to examine the distribution of C-reactive protein (CRP) and other markers of inflammation and their relationships with cardiovascular risk markers and renal disease in a remote Australian Aboriginal community. The study included 237 adults (58% of the adult population) in a remote Aboriginal community in the Northern Territory of Australia. Main outcome measures were CRP, fibrinogen and lgG concentrations, blood pressure (BP), presence of diabetes, lipids, albuminuria, seropositivity to three common micro-organisms, as well as carotid intima-media thickness (IMT). Serum concentrations of CRP [7 (5-13) mg/l; median (inter-quartile range)] were markedly increased and were significantly correlated with fibrinogen and lgG concentrations and inversely correlated with serum albumin concentration. Higher CRP concentrations were associated with lgG seropositivity to Helicobacter pylori and Chlamydia pneumoniae and higher lgG titre for cytomegalovirus. Higher CRP concentrations were associated with the following: the 45-54-year age group, female subjects, the presence of skin sores, higher body mass index, waist circumference, BP, glycated haemoglobin and greater albuminuria. CRP concentrations increased with the number of cardiovascular risk factors, carotid IMT and albuminuria independently of other risk factors. These CRP concentrations were markedly higher than described in other community settings and are probably related, in a large part, to chronic and repeated infections. Their association with markers of cardiovascular risk and renal disease are compatible with the high rates of cardiovascular and renal disease in this community, and provide more evidence of strong links between these conditions, through a shared background of infection/inflammation. This suggests that a strong focus on prevention and management of infections will be important in reducing these conditions, in addition to interventions directed at more traditional risk factors.

Smoking and elevated blood pressure are the most important risk factors for subarachnoid hemorrhage in the Asia-Pacific region - An overview of 26 cohorts involving 306,620 participants

Background and Purpose - The cause of subarachnoid hemorrhage ( SAH) is poorly understood and there are few large cohort studies of risk factors for SAH. We investigated the risk of SAH mortality and morbidity associated with common cardiovascular risk factors in the Asia-Pacific region and examined whether the strengths of these associations were different in Asian and Australasian ( predominantly white) populations. Methods - Cohort studies were identified from Internet electronic databases, searches of proceedings of meetings, and personal communication. Hazard ratios (HRs) for systolic blood pressure (SBP), current smoking, total serum cholesterol, body mass index (BMI), and alcohol drinking were calculated from Cox models that were stratified by sex and cohort and adjusted for age at risk. Results - Individual participant data from 26 prospective cohort studies ( total number of participants 306 620) that reported incident cases of SAH ( fatal and/or nonfatal) were available for analysis. During the median follow-up period of 8.2 years, a total of 236 incident cases of SAH were observed. Current smoking (HR, 2.4; 95% CI, 1.8 to 3.4) and SBP > 140 mm Hg ( HR, 2.0; 95% CI, 1.5 to 2.7) were significant and independent risk factors for SAH. Attributable risks of SAH associated with current smoking and elevated SBP ( similar to 140 mm Hg) were 29% and 19%, respectively. There were no significant associations between the risk of SAH and cholesterol, BMI, or drinking alcohol. The strength of the associations of the common cardiovascular risk factors with the risk of SAH did not differ much between Asian and Australasian regions. Conclusions - Cigarette smoking and SBP are the most important risk factors for SAH in the Asia-Pacific region.

Cardiovascular risk estimation by professionally active cardiovascular nurses: Results from the Basel 2005 Nurses Cohort

Background Nurses play a key role in the prevention of cardiovascular disease (CVD) and one would, therefore, expect them to have a heightened awareness of the need for systematic screening and their own CVD risk profile. The aim of this study was to examine personal awareness of CVD risk among a cohort of cardiovascular nurses attending a European conference. Methods Of the 340 delegates attending the 5th annual Spring Meeting on Cardiovascular Nursing (Basel, Switzerland, 2005), 287 (83%) completed a self-report questionnaire to assess their own risk factors for CVD. Delegates were also asked to give an estimation of their absolute total risk of experiencing a fatal CVD event in the next 10 years. Level of agreement between self-reported CVD risk estimation and their actual risk according to the SCORE risk assessment system was compared by calculating weighted Kappa (κw). Results Overall, 109 responders (38%) self-reported having either pre-existing CVD (only 2%), one or more markedly raised CVD risk factors, a high total risk of fatal CVD (≥ 5% in 10 years) or a strong family history of CVD. About half of this cohort (53%) did not know their own total cholesterol level. Less than half (45%) reported having a 10-year risk of fatal CVD of < 1%, while 13% reported having a risk ≥ 5%. Based on the SCORE risk function, the estimated 10-year risk of a fatal CVD event was < 1% for 96% of responders: only 2% had a ≥ 5% risk of such an event. Overall, less than half (46%) of this cohort's self-reported CVD risk corresponded with that calculated using the SCORE risk function (κw = 0.27). Conclusion Most cardiovascular nurses attending a European conference in 2005 poorly understood their own CVD risk profile, and the agreement between their self-reported 10-year risk of a fatal CVD and their CVD risk using SCORE was only fair. Given the specialist nature of this conference, our findings clearly demonstrate a need to improve overall nursing awareness of the role and importance of systematic CVD risk assessment.

Cardiovascular disease and PPARdelta: Targeting the risk factors

Metabolism, in part, is regulated by the peroxisome proliferator-activated receptors (PPARs). The PPARs act as nutritional lipid sensors and three mammalian PPAR subtypes designated PPARalpha (NR1C1), PPARgamma (NR1C3) and PPARdelta (NR1C2) have been identified. This subgroup of nuclear hormone receptors binds DNA and controls gene expression at the nexus of pathways that regulate lipid and glucose homeostasis, energy storage and expenditure in an organ-specific manner. Recent evidence has demonstrated activation of PPARdelta in the major mass peripheral tissue (ie, adipose and skeletal muscle). It enhances glucose tolerance, insulin-stimulated glucose disposal, lipid catabolism, energy expenditure, cholesterol efflux and oxygen consumption. These effects positively influence the blood-lipid profile. Furthermore, PPARdelta activation produces a predominant type I/slow twitch/oxidative muscle fiber phenotype that leads to increased endurance, insulin sensitivity and resistance to obesity. PPARdelta has rapidly emerged as a potential target in the battle against dyslipidemia, insulin insensitivity, type II diabetes and obesity, with therapeutic efficacy in the treatment of cardiovascular disease risk factors. GW-501516 is currently undergoing phase II safety and efficacy trials in human volunteers for the treatment of dyslipidemia. The outcome of these clinical trials are eagerly awaited against a background of conflicting reports about cancer risks in genetically predisposed animal models. This review focuses on the potential pharmacological utility of selective PPARdelta agonists in the context of risk factors associated with metabolic and cardiovascular disease.