Association between various anthropometric measures of obesity and markers of subclinical atherosclerosis.

Central obesity is a known cardiovascular risk factor and measures of visceral obesity are known to predict atherosclerosis. This study sought to explore the association between various anthropometric measures and markers of subclinical atherosclerosis (MoSCA) among low risk healthy individuals. Multi-Ethnic Study of Atherosclerosis (MESA) is a population-based study of Caucasian (38%), Afro-American (28%), Chinese (22%) and Hispanic (12%) subjects, aged 45-84 years, free from clinical cardiovascular disease. We performed a post hoc analysis of the limited access dataset of MESA subjects to evaluate the association between carotid intima media thickness and coronary artery calcium score (CACS), as MoSCA and various measures of obesity. Multivariable regression analyses adjusted for traditional cardiovascular risk factors, ethnicity and C-reactive protein were performed. Each unit increase in waist-hip ratio was strongly associated with increase in both common and internal carotid intima media thickness (beta: 0.12, 95% confidence interval (CI): 0.06 to 0.18, p < 0.001 and beta: 0.23, 95% CI: 0.03 to 0.43, p = 0.021, respectively). Measures of central obesity were superior to body mass index as demonstrated by their consistent association with each category of CACS when compared to the reference category (CACS = 0). Compared to body mass index, measures of visceral obesity were significantly associated with MoSCA in this multiethnic healthy population. Waist-hip ratio seems to be more consistent in its association with various MoSCA compared to other anthropometric measures.

The association of red cell distribution width with glycated hemoglobin among healthy adults without diabetes mellitus.

BACKGROUND: Red cell distribution width (RDW) and hemoglobin A1c (HbA1c) are both known to be predictive of future cardiovascular disease (CVD). OBJECTIVE: We hypothesized that RDW would be associated with HbA1c in adults without diabetes independent of fasting blood glucose (FBG). METHODS: This cross-sectional study included 15,343 nondiabetic adults, free of CVD, enrolled in NHANES 1999-2008. Adjusted means of RDW were calculated across HbA1c categories for the overall population. Multivariable regression analyses were performed analyzing the association between RDW and HbA1c for individuals with available data on FBG (n = 7,454). RESULTS: RDW significantly correlated with HbA1c (r = 0.27, p < 0.001; n = 15,343), with a gradual increase in adjusted mean RDW across HbA1c categories (12.59% ± 0.02% in the group with HbA1c ≤4.8% vs. 12.92% ± 0.02% in the group with HbA1c >5.8%, p < 0.001 for trend). In regression analyses, RDW independently predicted HbA1c (ß-coefficient 0.034, 95% CI 0.026-0.042, p < 0.001). CONCLUSION: RDW significantly predicts HbA1c independent of FBG in healthy nondiabetic adults, suggesting the possibility of chronic hyperglycemia mediating the association between RDW and CVD.

A gender-stratified comparative analysis of various definitions of metabolic syndrome and cardiovascular risk in a multiethnic U.S. population.

INTRODUCTION: We sought to evaluate the ability of various metabolic syndrome definitions in predicting primary cardiovascular disease (CVD) outcomes in a vast multiethnic U.S. cohort. METHODS: This study included 6,814 self-identified men and women aged 45-84 years enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA) study. Gender-stratified analyses were performed to calculate hazard ratios of CVD, stroke, and mortality associated with various metabolic syndrome definitions and their individual constructs. RESULTS: The hazard ratios [95% confidence interval (CI)] for all-cause CVD in men were 2.90 (2.18-3.85), 2.64 (1.98-3.51), 2.16 (1.62-2.88), 2.56 (1.91-3.44), 1.82 (1.35-2.46), and 2.92 (2.15-3.95) for the National Cholesterol Education Program (NCEP), American Heart Association (AHA), World Health Organization (WHO), International Diabetes Federation (IDF), European Group for the Study of Insulin Resistance (EGIR), and the newly defined consensus criteria. Hazard ratios in women were 2.11 (1.41-3.15), 2.17 (1.45-3.27), 2.04 (1.37-3.06), 1.91 (1.27-2.88), 1.85 (1.23-2.79), and 2.08 (1.37-3.14), respectively. Metabolic syndrome was strongly associated with stroke risk only in males. In men, all constitutive metabolic syndrome components were continuously and strongly associated with CVD. In women, high-density lipoprotein and triglycerides did not appear to be associated with short term CVD risk. CONCLUSION: We found the newly defined consensus criteria for metabolic syndrome to be similarly predictive of cardiovascular events when compared to existing definitions. Significant gender differences exist in the association between metabolic syndrome, its individual components, and CVD.

Predictors of residual cardiovascular risk in patients on statin therapy for primary prevention.

BACKGROUND: Low-density lipoprotein cholesterol-lowering therapy is an important aspect of primary prevention of cardiovascular disease (CVD). Statins are the most widely used drug therapy for achieving low-density lipoprotein goals based on an individual's 10-year risk. However, substantial risk of CVD events still exists even when a person is on statins. We sought to explore the predictors of future CVD events in individuals on statins with no pre-existing CVD. METHODS: The analysis was done on subjects who were on statins (n = 919) at baseline in the Multi-Ethnic Study of Atherosclerosis limited access dataset from the National Heart, Lung and Blood Institute. The primary outcome variable was all-cause CVD events (n = 67). Multivariate regression Cox proportional hazard analysis was done to identify potential independent predictors of all-cause CVD. RESULTS: Our cohort consisted of 47% males, with a mean age of 66 ± 9 years. Sixty-seven participants (7.3%) experienced CVD events during a mean follow-up of 4.4 years. A higher coronary artery calcium score, homocysteine levels, waist circumference and a lower large arterial elasticity index were identified as independent predictors of CVD events. CONCLUSION: Homocysteine, waist circumference, coronary artery calcification and the large artery elasticity index appear to be the major independent predictors of CVD events in individuals on statins with no pre-existing CVD. In addition to emphasizing weight loss, alternative approaches beyond lipid reduction may need to be explored to better characterize and attenuate the residual risk in subjects on statin therapy for primary prevention.

Glycosylated hemoglobin and prevalent metabolic syndrome in nondiabetic multiethnic U.S. adults.

BACKGROUND: Metabolic syndrome poses a significant risk for cardiovascular disease. Recently, glycosylated hemoglobin (HbA1c) has been included in the diagnostic criteria for diabetes mellitus and prediabetes. We sought to determine if HbA1c is associated with prevalent metabolic syndrome in nondiabetic U.S. adults. METHODS: A total of 9,022 nondiabetic participants of National Health and Nutrition Examination Surveys 1999-2008 (age, 47.5 ± 18.3 years, 51% females) were divided into quintiles (Q) of HbA1c: Q1 (reference), ≤5%; Q2, 5.1%-5.3%; Q3, 5.4%-5.5%; Q4, 5.6%-5.7%; and Q5, ≥5.8%. Modified National Cholesterol Education Program Adult Treatment Panel III criteria were used to identify metabolic syndrome (n=2,821; 31.3%). Unadjusted and adjusted multivariate logistic regression analysis was performed to assess the risk of metabolic syndrome. RESULTS: A graded increase in odds of having prevalent metabolic syndrome with increase from each quintile of HbA1c compared to Q1 was observed after adjusting for age, sex, race, body mass index (BMI), total cholesterol, lipid-lowering therapy, current smoking, family history of diabetes, C-reactive protein, and fasting insulin. Stratified analysis based on gender, ethnicity, and BMI showed similar results. The HbA1c value of ≥5.4% remained appropriate cutoff for predicting metabolic syndrome in Caucasians and Hispanics, whereas ≥5.6% provided the best accuracy for African Americans based on receiver operating characteristics analysis. CONCLUSION: HbA1c much below the level for prediabetes was associated with prevalence of the metabolic syndrome in a cohort of nondiabetic U.S. adults. HbA1c can be considered as a surrogate marker for metabolic syndrome in nondiabetics.

Comparison of five-year outcome in African Americans versus Caucasians following percutaneous coronary intervention.

BACKGROUND: Studies regarding short-term outcomes after percutaneous coronary intervention (PCI) have reported no ethnic differences and data on long-term follow-up is conflicting and sparse. METHODS: 730 consecutive patients (67% African American) undergoing PCI from January 1999 to December 2000 at a tertiary care center in Detroit, MI, were followed up. End points studied included either all cause mortality collected from Social Security Death Index or first hospital admission after the index procedure due to myocardial infarction(MI), congestive heart failure(CHF), and revascularization (PCI or coronary artery bypass graft surgery). RESULTS: African-Americans undergoing PCI had significant differences in baseline cardiovascular co-morbidity and were more likely to present with acute myocardial infarction than Caucasians. On Kaplan Meier survival analysis and log rank test, each ethnic group had equivalent survival for cumulative end points upto 6-month follow-up, however longer follow-up to 5 year was characterized by lower survival rate in African Americans compared to Caucasians (41% vs. 54%, log rank P 0.01). After adjustment for potential confounders, AA ethnicity (Adjusted HR 1.62, 95% CI 1.01-1.28, P 0.04) remained a predictor of adverse cardiac outcome (Death/MI/CHF) at five-year follow-up (Cox regression propensity adjusted hazard analysis). CONCLUSIONS: African American patients undergoing PCI had unfavorable baseline cardiovascular characteristics but comparable short-term outcome compared to whites. However, at 5-year follow-up, African Americans had worse clinical outcome, higher incidence of acute myocardial infarction, congestive heart failure and significantly lower long-term survival.