The Association between the Triglyceride to High-density Lipoprotein Cholesterol Ratio and Low-density Lipoprotein Subclasses

Use of lipid ratios to predict vascular target organ damage in youth

BACKGROUND

Elevated lipid levels are risk factors for early atherosclerosis. Lipid ratios have emerged as potentially stronger predictors of adverse cardiovascular changes and atherogenic cholesterol. Risk stratification in youth with obesity or type 2 diabetes may be improved by using lipid ratios. We sought to determine if lipid ratios would identify abnormalities in arterial structure and stiffness in adolescents and young adults.

METHODS

A total of 762 youth aged 10-24 years had laboratory, anthropometric, blood pressure, and carotid intima-media thickness and arterial stiffness data collected. Subjects were stratified into tertiles (low, mid, high) of lipid ratios and non-high-density lipoprotein cholesterol (HDL-C). Vascular outcomes by tertile were assessed by analyses of variance. General linear models were constructed for each lipid value and included demographics, risk factors and vascular measures. Correlations between lipid markers, vascular measures, and low-density lipoprotein (LDL) particle size and number were conducted.

RESULTS

There was a progressive increase in arterial thickness and stiffness across all three lipid ratios and non-HDL-C. The triglyceride to HDL-C (TG/HDL-C) ratio remained an independent predictor of arterial thickness and stiffness after adjusting for other cardiovascular risk factors. TG/HDL-C had the highest correlations with arterial stiffness and small, dense LDL.

CONCLUSIONS

Arterial stiffness is increased in youth with high lipid ratios with TG/HDL-C being the most consistent marker of vascular changes. These data suggest that identification of high TG/HDL-C in these individuals may lead to earlier intervention to prevent atherosclerotic cardiovascular disease.

Oxidative Stress, Atherogenic Dyslipidemia, and Cardiovascular Risk

Oxidative stress is the consequence of an overproduction of reactive oxygen species (ROS) that exceeds the antioxidant defense mechanisms. Increased levels of ROS contribute to the development of cardiovascular disorders through oxidative damage to macromolecules, particularly by oxidation of plasma lipoproteins. One of the most prominent features of atherogenic dyslipidemia is plasma accumulation of small dense LDL (sdLDL) particles, characterized by an increased susceptibility to oxidation. Indeed, a considerable and diverse body of evidence from animal models and epidemiological studies was generated supporting oxidative modification of sdLDL particles as the earliest event in atherogenesis. Lipid peroxidation of LDL particles results in the formation of various bioactive species that contribute to the atherosclerotic process through different pathophysiological mechanisms, including foam cell formation, direct detrimental effects, and receptor-mediated activation of pro-inflammatory signaling pathways. In this paper, we will discuss recent data on the pathophysiological role of oxidative stress and atherogenic dyslipidemia and their interplay in the development of atherosclerosis. In addition, a special focus will be placed on the clinical applicability of novel, promising biomarkers of these processes.

The Importance of Metabolic and Environmental Factors in the Occurrence of Oxidative Stress during Pregnancy

Metabolic changes in pregnant women begin in the first weeks after conception under the influence of placental hormones that affect the metabolism of all nutrients. An increased concentration of total lipids accompanies pregnancy and an increased accumulation of triglycerides in low-density lipoproteins (LDL) particles. Lipids in small dense LDL particles are more susceptible to oxidative modification than normal-density LDL particles. Unlike LDL high-density lipoproteins (HDL), lipoprotein particles have an atheroprotective role in lipid metabolism. The very growth of the fetus depends on the nutrition of both parents, so obesity is not only in the mother but also in the father. Nutritional programming of the offspring occurs through changes in lipid metabolism and leads to an increased risk for cardiometabolic diseases. Pregnancy is accompanied by an increased need for oxygen in the mitochondria of the placenta and a tendency to develop oxidative stress. Oxidative stress represents a disturbance in the balance of oxidation-reduction processes in the body that occurs due to the excessive production of free oxygen radicals that cellular homeostatic mechanisms are unable to neutralize. When the balance with the antioxidant system is disturbed, which happens when free oxygen radicals are in high concentrations, serious damage to biological molecules occurs, resulting in a series of pathophysiological and pathological changes, including cell death. Therefore, oxidative stress plays a significant role in the pathogenesis of many complications that can occur during pregnancy. The oxidative status of pregnant women is also influenced by socioeconomic living conditions, lifestyle habits, diet, smoking, and exposure to environmental air pollution. During a healthy pregnancy, the altered lipid profile and oxidative stress create an increased risk for premature birth and pregnancy-related diseases, and a predisposition to adult diseases.

Non-traditional lipid profiles and the risk of stroke: A systematic review and meta-analysis

AIMS

An increasing number of studies on non-traditional lipid profiles have been investigated in recent years. However, the associations between non-traditional lipid profiles and the risk of stroke remained inconsistent. Therefore, this meta-analysis aimed to evaluate the associations between non-traditional lipid profiles and the risk of stroke and clarify the dose-response relations.

DATA SYNTHESIS

We performed a systematic literature search in PubMed, Embase, and Web of Science databases until 1 November 2022 for relevant studies. Relative risks and 95% confidence intervals were pooled by random-effects or fixed-effects models. A total of 26 full-text studies with 676678 participants and 18057 stroke cases were eligible for the final study. We found a positive association between the risk of stroke and total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio (RR = 1.19,95%CI = 1.00-1.40, I² = 74.6%), triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio (RR = 1.24,95%CI = 1.10-1.41, I² = 62.8%) or low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C) ratio (RR = 1.24, 95%CI = 1.11-1.39, I² = 49.4%). When focusing on the stroke subtype, a more significant association was observed between the risk of ischemic stroke and four non-traditional lipid profiles. In dose-response analysis, we found a linear association between TC/HDL-C ratio and the risk of stroke (RR = 1.16,95%CI = 1.07-1.26).

CONCLUSIONS

Elevated non-traditional lipid profiles were associated with an increased risk of ischemic stroke. The linear association showed the risk of stroke increased by 16% when the pooled RR of TC/HDL-C ratio per 1-unit increased.

REGISTRATION NUMBER IN PROSPERO

CRD42022321251.

Atherogenic index of plasma is an independent predictor of mitral annular calcification

BACKGROUND

In the latest reports, atherogenic indices have been related to acute coronary syndromes, stable coronary artery disease, heart failure and future cardiac events. Conventional atherosclerosis risk factors have been associated with mitral annular calcification (MAC), but data on the relationship between atherogenic indices and MAC are lacking. We aimed to investigate a possible relationship between MAC and atherogenic indices.

METHODS

In total 741 patients (n = 427 with MAC and n = 314 without MAC) who were examined in our cardiology clinic from February 2016 to October 2021 were recruited in the study. Mitral annular calcification was diagnosed by transthoracic 2-dimensional echocardiography. The atherogenic coefficient (AC), Castelli risk index 1 (CRI-1), Castelli risk index 2 (CRI-2) and atherogenic index of plasma (AIP) were calculated by utilizing standard lipid test values.

RESULTS

There was no statistically significant difference in sex, age, diabetes and hypertension status between the patient and the control groups. Serum triglyceride level, AIP, Hs-CRP, smoking and BMI were independently significantly associated with MAC in multiple regression analysis (p < 0.001).

CONCLUSION

Higher AIP was related to the existence of MAC and also predict the presence of MAC independently. Studies evaluating the modification of these indices are needed.

Correlations between Diabetes Mellitus Self-Care Activities and Glycaemic Control in the Adult Population: A Cross-Sectional Study

Although it is well known that lifestyle changes can affect plasma glucose levels, there is little formal evidence for the sustained effectiveness of exercise and diet in diabetes mellitus (DM) management. Self-care in DM refers to the real-life application of the knowledge that the patient gained during the education programmes. The goals are to bring about changes in the patient's behaviour, thus improving glycaemic control. We evaluated the influence of DM self-care activities (SCA) on glycaemic control in a total of 159 patients with DM. Plasma glycated haemoglobin (HbA1c) levels were used to monitor glycaemic control, while SCA were assessed using the standardised Diabetes Self-Management Questionnaire (DSMQ). In our study, 53% of the patients had a HbA1c ≥ 7%. In univariate linear regression models, a statistically significant inverse association was observed between the HbA1c (the dependent variable) and both the DSMQ Dietary Control Score (R2 = 0.037, p = 0.0145) and the DSMQ Sum Score (R2 = 0.06, p = 0.0014). The mean absolute change in the HbA1c% associated with one standard deviation (SD) change in the DSMQ Sum Score, independent of the other significant variables retained in the compacted multivariate regression model, was -0.419% (confidence interval: 95%: from -0.18 to -0.65). Although the impact of the DSMQ Score was modest when compared to the other independent variables in the multivariate model, the findings emphasise the importance of maintaining optimal lifestyle changes to avoid hyperglycaemia and its complications. In conclusion, enhanced self-management of DM is associated with improved glucose control. In patients with chronic diseases such as DM, the role of streamlining SCA encompassing physical activity and proper dietary choices is imperative because of a significantly reduced access to healthcare globally as a result of the COVID-19 pandemic.

Elevated LDL Cholesterol with a Carbohydrate-Restricted Diet: Evidence for a "Lean Mass Hyper-Responder" Phenotype

BACKGROUND

People commencing a carbohydrate-restricted diet (CRD) experience markedly heterogenous responses in LDL cholesterol, ranging from extreme elevations to reductions.

OBJECTIVES

The aim was to elucidate possible sources of heterogeneity in LDL cholesterol response to a CRD and thereby identify individuals who may be at risk for LDL cholesterol elevation.

METHODS

Hypothesis-naive analyses were conducted on web survey data from 548 adults consuming a CRD. Univariate and multivariate regression models and regression trees were built to evaluate the interaction between body mass index (BMI) and baseline lipid markers. Data were also collected from a case series of five clinical patients with extremely high LDL cholesterol consuming a CRD.

RESULTS

BMI was inversely associated with LDL cholesterol change. Low triglyceride (TG) to HDL cholesterol ratio, a marker of good metabolic health, predicted larger LDL cholesterol increases. A subgroup of respondents with LDL cholesterol ≥200 mg/dL, HDL cholesterol ≥80 mg/dL, and TG ≤70 mg/dL were characterized as "lean mass hyper-responders." Respondents with this phenotype (n = 100) had a lower BMI and, remarkably, similar prior LDL cholesterol versus other respondents. In the case series, moderate reintroduction of carbohydrate produced a marked decrease in LDL cholesterol.

CONCLUSIONS

These data suggest that, in contrast to the typical pattern of dyslipidemia, greater LDL cholesterol elevation on a CRD tends to occur in the context of otherwise low cardiometabolic risk.

Plasma atherogenic indices are independent predictors of slow coronary flow

Background

Although the pathophysiology of coronary slow flow (CSF) has not been fully elucidated, emerging data increasingly support potential role for subclinical diffuse atherosclerosis in the etiology of CSF. We aimed to investigate relationship between atherogenic indices and CSF.

Methods

130 patients with CSF diagnosed according to Thrombolysis in Myocardial Infarction (TIMI)-frame count (TFC) method and 130 controls who had normal coronary flow (NCF) were included in this retrospective study. Atherogenic indices (atherogenic index of plasma [AIP], Castelli risk indices I and II [CRI-I and II]) were calculated using conventional lipid parameters.

Results

The logistic regression analyses demonstrated that AIP (OR, 5.463; 95% confidence interval [CI], 1.357–21.991; p = 0.017) and CRI-II (OR, 1.624; 95% CI, 1.138–2.319; p = 0.008) were independent predictors of CSF. Receiver operating characteristic analysis showed that the optimal cutoff value to predict the occurrence of CSF was 0.66 for AIP (sensitivity, 59%; specificity, 73%; area under curve [AUC], 0.695; p < 0.001) and 3.27 for CRI-II (sensitivity, 60%; specificity, 79%; AUC, 0.726; p < 0.001).

Conclusions

AIP and CRI-II levels were independent predictors of CSF. Prospective studies in larger cohorts of patients may elucidate the role of atherogenic dyslipidemia in the pathophysiology of CSF.

Predictive Value of the Triglyceride to High-Density Lipoprotein Cholesterol Ratio for All-Cause Mortality and Cardiovascular Death in Diabetic Patients With Coronary Artery Disease Treated With Statins

Background and Aims: Studies have highlighted the role of the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio on subsequent cardiovascular events. However, the association of the TG/HDL-C ratio with survival outcomes in diabetic patients with coronary artery disease (CAD) treated with statins remains unknown. This study aimed to assess the predictive value of the TG/HDL-C ratio for all-cause mortality and cardiovascular death in diabetic patients with CAD treated with statins. Methods: The data of patients with type 2 diabetes and angiographically-confirmed CAD who were undergoing statin therapy and visited Tianjin Chest Hospital between January 2016 and September 2016 were retrospectively collected. The patients were categorized based on the baseline TG/HDL-C ratio tertile. Kaplan-Meier analysis and multivariate Cox proportional hazard regression were applied to assess the role of the TG/HDL-C ratio in predicting all-cause mortality and cardiovascular death. Results: A total of 2,080 patients were included. During the 4-year follow-up, 209 patients died, 136 of whom from cardiovascular death. The Kaplan-Meier analyses showed that an increased TG/HDL-C ratio was associated with an increased risk of all-cause mortality (P < 0.001) and cardiovascular death (P < 0.001). The multivariate cox hazard regression analysis revealed a similar effect of the TG/HDL-C ratio on the risk of all-cause mortality (P = 0.046) and cardiovascular death (P = 0.009). The role of the TG/HDL-C ratio in predicting all-cause mortality and cardiovascular death was similar among all subgroups (P > 0.050). For all-cause mortality, the TG/HDL-C ratio significantly improved the C-statistic from 0.799 to 0.812 (P = 0.018), and the net reclassification index (NRI) and integrated discrimination index (IDI) were 0.252 (95% CI: 0.112-0.392; P < 0.001) and 0.012 (95% CI: 0.003-0.022; P = 0.012), respectively. Similarly, for cardiovascular death, the TG/HDL-C ratio significantly improved the C-statistic from 0.771 to 0.804 (P < 0.001), and the NRI and IDI were 0.508 (95% CI: 0.335-0.680; P < 0.001) and 0.033 (95% CI: 0.015-0.050; P < 0.001). Conclusion: TG/HDL-C ratio might be useful for predicting all-cause mortality and cardiovascular death in diabetic patients with CAD treated with statins.