Management of atherogenic dyslipidemia of the metabolic syndrome: evolving rationale for combined drug therapy

Association of lipid profile and BMI Z-score in southern Iranian children and adolescents

Background Heart disease has been the leading cause of death for decades in the US population. Dyslipidemia is the most important risk factor for cardiovascular disease (CVD), and it often starts during childhood. Methods This cross-sectional study was performed in a growth assessment clinic in the city of Shiraz to determine the relation between body mass index (BMI) and dyslipidemia among children and teenagers aged 2-18 years. Nine hundred and eighty-nine children including 422 boys and 567 girls were selected. Results Adjusted for age and gender, total cholesterol (TC) (r = 0.172, p = 0.000), low-density lipoprotein cholesterol (LDL-c) (r = 0.176, p = 0.000), non-high-density lipoprotein cholesterol (non-HDL-c) (r = 0.227, p = 0.000) and triglycerides (TG) (r = 0.253, p = 0.000) showed a significant positive correlation with BMI Z-score, and HDL-c showed a significant negative correlation with BMI Z-score (r = -0.131, p = 0.000). Adjusted for age and gender, overweight and obese children were 1.882 times more likely to have high TC levels (p = 0.009), 2.236 times more likely to have high non-HDL-c levels (p = 0.000) and 3.176 times more likely to have high TG levels (p = 0.000) in comparison with children who had a healthy weight. Obese children had the highest percentage of isolated TG dyslipidemia (23.1%) and underweight children had the highest percentage of isolated HDL dyslipidemia (15.6%). Conclusions There is a strong link between atherosclerotic cardiovascular disease (ASCVD) and the level of blood lipids and between blood lipids and BMI Z-score. The first step in preventing ASCVD is the reduction of blood lipids, preventing weight gain and loss of extra weight.

Moderate to High Levels of Cardiorespiratory Fitness Attenuate the Effects of Triglyceride to High-Density Lipoprotein Cholesterol Ratio on Coronary Heart Disease Mortality in Men

OBJECTIVE

To examine the prospective relationships among cardiorespiratory fitness (CRF), fasting blood triglyceride to high density lipoprotein cholesterol ratio (TG:HDL-C), and coronary heart disease (CHD) mortality in men.

METHODS

A total of 40,269 men received a comprehensive baseline clinical examination between January 1, 1978, and December 31, 2010. Their CRF was determined from a maximal treadmill exercise test. Participants were divided into CRF categories of low, moderate, and high fit by age group and by TG:HDL-C quartiles. Hazard ratios for CHD mortality were computed using Cox regression analysis.

RESULTS

A total of 556 deaths due to CHD occurred during a mean ± SD of 16.6±9.7 years (669,678 man-years) of follow-up. A significant positive trend in adjusted CHD mortality was shown across decreasing CRF categories (P for trend<.01). Adjusted hazard ratios were significantly higher across increasing TG:HDL-C quartiles as well (P for trend<.01). When grouped by CRF category and TG:HDL-C quartile, there was a significant positive trend (P=.04) in CHD mortality across decreasing CRF categories in each TG:HDL-C quartile.

CONCLUSION

Both CRF and TG:HDL-C are significantly associated with CHD mortality in men. The risk of CHD mortality in each TG:HDL-C quartile was significantly attenuated in men with moderate to high CRF compared with men with low CRF. These results suggest that assessment of CRF and TG:HDL-C should be included for routine CHD mortality risk assessment and risk management.

10-Year Trends in Serum Lipid Levels and Dyslipidemia Among Children and Adolescents From Several Schools in Beijing, China

Background

Serum lipid trends in children and adolescents are predictors of the future prevalence of cardiovascular disease in adults.

Methods

Data were obtained from cross-sectional studies conducted in 2004 and 2014. A total of 3249 children aged 6–18 years were included in the present study; serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were measured.

Results

Overall, upward trends in mean TC, non-HDL-C, and LDL-C levels, and in geometric mean TG levels, were observed (all P < 0.001). Mean HDL-C levels significantly decreased between 2004 and 2014 (from 1.54 mmol/L to 1.47 mmol/L; P < 0.001). The prevalence of abnormal levels of serum lipids, with the exception of the prevalence of low HDL-C (P = 0.503), significantly increased over the study period (all P < 0.05). The prevalence of hyperlipidemia (from 13.3%; 95% confidence interval [CI], 11.6%–15.0% to 24.5%; 95% CI, 22.4%–26.6%; P < 0.001) and dyslipidemia (from 18.8%; 95% CI, 16.9%–20.7% to 28.9%; 95% CI, 26.7%–31.3%; P < 0.001) also increased from 2004 to 2014. The prevalence of abnormal serum lipids increased, and mean serum lipid levels, with the exception of TC levels, worsened in subjects with obesity compared with non-overweight subjects, as well as in subjects with mixed obesity compared with non-obese subjects (P < 0.05 for all).

Conclusions

Adverse trends in serum lipid concentrations over the past 10 years were observed among children aged 6–9 years, with the exception of specific lipids, and among adolescents aged 10–18 years, from several schools in Beijing, China.

Differences in the distribution of risk factors for stroke among the high-risk population in urban and rural areas of Eastern China

INTRODUCTION

Considering the program of screening for risk factors of stroke in Eastern China, the aim of this study was to compare the distribution differences in risk factors for stroke among the high-risk population living in urban and rural areas.

METHODS

A total of 231,289 residents were screened and basic information collected. Risk factors for stroke among the high-risk population were compared between the urban and rural groups.

RESULTS

A total of 117,776 high-risk residents from urban areas and 113,513 from rural areas were included in the analysis. The prevalence of hypertension was much higher in rural areas (73.3%) than that in urban areas (64.1%). Dyslipidemia (48.9% vs. 26.9%), sport lack (46.6% vs. 31.6%), diabetes mellitus (21.3% vs. 16.5%), and atrial fibrillation (18.7% vs. 9.8%) were more prevalent in the urban group, while smoking (26.5% vs. 28.8%), previous stroke (10.1% vs. 16.9%), and transient ischemic attack (20.9% vs. 24.6%) were less prevalent.

CONCLUSION

Among the population at high risk of stroke, there were significant differences in the distribution of the following risk factors between the urban and rural groups: hypertension, atrial fibrillation, dyslipidemia, lack of physical exercise, and a previous stroke.

Obesity and dyslipidemia in South Asians

Obesity and dyslipidemia are emerging as major public health challenges in South Asian countries. The prevalence of obesity is more in urban areas than rural, and women are more affected than men. Further, obesity in childhood and adolescents is rising rapidly. Obesity in South Asians has characteristic features: high prevalence of abdominal obesity, with more intra-abdominal and truncal subcutaneous adiposity than white Caucasians. In addition, there is greater accumulation of fat at “ectopic” sites, namely the liver and skeletal muscles. All these features lead to higher magnitude of insulin resistance, and its concomitant metabolic disorders (the metabolic syndrome) including atherogenic dyslipidemia. Because of the occurrence of type 2 diabetes, dyslipidemia and other cardiovascular morbidities at a lower range of body mass index (BMI) and waist circumference (WC), it is proposed that cut-offs for both measures of obesity should be lower (BMI 23–24.9 kg/m² for overweight and ≥25 kg/m² for obesity, WC ≥80 cm for women and ≥90 cm for men for abdominal obesity) for South Asians, and a consensus guideline for these revised measures has been developed for Asian Indians. Increasing obesity and dyslipidemia in South Asians is primarily driven by nutrition, lifestyle and demographic transitions, increasingly faulty diets and physical inactivity, in the background of genetic predisposition. Dietary guidelines for prevention of obesity and diabetes, and physical activity guidelines for Asian Indians are now available. Intervention programs with emphasis on improving knowledge, attitude and practices regarding healthy nutrition, physical activity and stress management need to be implemented. Evidence for successful intervention program for prevention of childhood obesity and for prevention of diabetes is available for Asian Indians, and could be applied to all South Asian countries with similar cultural and lifestyle profiles. Finally, more research on pathophysiology, guidelines for cut-offs, and culturally-specific lifestyle management of obesity, dyslipidemia and the metabolic syndrome are needed for South Asians.

The metabolic basis of atherogenic dyslipidemia

Atherogenic dyslipidemia is one of the major components of the metabolic syndrome, a complex cluster of several risk factors within a single patient that according to the National Cholesterol Education Program (NCEP) Adult Treatment Panel III includes at least 3 of the following: large waist circumference, elevated triglyceride levels, low levels of high-density lipoprotein cholesterol (HDL-C), hypertension, and elevated fasting glucose levels, which are directly related to the incidence of coronary heart disease. Atherogenic dyslipidemia clinically presents as elevated serum triglyceride levels, increased levels of small dense low-density lipoprotein (sdLDL) particles, and decreased levels of HDL-C. An important component of atherogenic dyslipidemia is central obesity, which is defined as increased waist circumference and has recently been identified as a chief predictor of the metabolic syndrome in certain patients. Another recent study found that both body mass index and waist circumference were highly predictive of eventual development of the metabolic syndrome. Because atherogenic dyslipidemia usually precedes the clinical manifestation of the metabolic syndrome, strategies to treat it are the focus of pharmacologic intervention. For example, the 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors, commonly known as statins, benefit hypercholesterolemic patients who have atherogenic dyslipidemia that is associated with the metabolic syndrome. Pioglitazone, an antidiabetic agent that acts primarily by decreasing insulin resistance, improves sensitivity to insulin in muscle and adipose tissue and inhibits hepatic gluconeogenesis. Pioglitazone improves glycemic control while reducing circulating insulin levels. The investigational agent, rimonabant--a centrally and peripherally acting, selective cannabinoid type-1 receptor blocker--is the first therapy developed for managing several cardiovascular risk factors at one time. Rimonabant has shown promise in attacking atherogenic dyslipidemia from several vantage points by affecting glucose, HDL-C, triglycerides, and waist circumference in patients who are prone to atherogenic dyslipidemia.

Statin safety: an overview and assessment of the data--2005

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statin drugs, have been studied in numerous controlled human research trials involving hundreds of thousands of study participants. Statins have been prescribed for millions of patients. Based on this vast research and clinical experience, statins have been shown to improve lipid blood levels and reduce atherosclerotic coronary artery disease (CAD) risk, resulting in reduced CAD morbidity and mortality, and in several studies, reduced overall ("all-cause") mortality. From a safety perspective, both research trial evidence and clinical practice experience have demonstrated that statins are generally well tolerated. However, as with all pharmaceuticals, safety considerations exist with both monotherapy and combination statin therapy, mainly involving potential adverse effects on muscle, liver, kidney, and the nervous system. The evidence supporting statin-related potential adverse experiences on these organ systems is sometimes strong and based on clear clinical trial evidence (such as the increased risk of muscle enzyme elevation with higher statin doses). The evidence is at other times more speculative, being based on case reports and inconclusive clinical trial data (such as possible favorable or unfavorable effects of statins on cognition). Because the use of statins is so widespread, it is useful for the clinician to understand statin safety issues and the level of available evidence supporting the contention that various adverse effects are caused by statins. This review presents an assessment of statin safety based on an overview of the current statin safety data and their clinical implications.

Atherogenic dyslipidemia associated with metabolic syndrome and insulin resistance

Atherogenic dyslipidemia, a component of metabolic syndrome, is characterized by high levels of apolipoprotein B (apo B)-containing lipoproteins, including very-low-density lipoprotein remnants and small low-density lipoprotein particles, and reduced levels of high-density lipoprotein cholesterol. Although the National Cholesterol Education Program Adult Treatment Panel III includes elevations in blood pressure and plasma glucose in the definition of metabolic syndrome, the broader scope of metabolic syndrome includes proinflammatory and prothrombotic states, which derive from the secretory activity of adipose tissue. Abdominal fat can adversely affect insulin action and the disposal of glucose through an increase in the release of free fatty acid, resulting in accumulation of triglyceride in muscle and liver, thereby depressing insulin action and increasing output of apo B-containing lipoproteins. Impaired regulation of adipokines, bioactive substances secreted from adipose tissue, likely produces systemic inflammation, which can promote atherogenesis. Insulin resistance is recognized as an important metabolic defect linking the components of metabolic syndrome. One molecule that may play an important role in metabolic syndrome to regulate metabolic and vascular pathways is the peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Studies have established PPAR-gamma deficiency as a cause of lipodystrophy and confirmed its adipogenic role. Patients with atherogenic dyslipidemia and metabolic syndrome should undergo global risk assessment for cardiovascular disease and future cardiovascular events to determine an overall treatment strategy.