Remnant Cholesterol, Not LDL Cholesterol, Explains Peripheral Artery Disease Risk Conferred by apoB: A Cohort Study.

BACKGROUND: Elevated apoB-containing lipoproteins (=remnants+LDLs [low-density lipoproteins]) are a major risk factor for atherosclerotic cardiovascular disease, including peripheral artery disease (PAD) and myocardial infarction. We tested the hypothesis that remnants and LDL both explain part of the increased risk of PAD conferred by elevated apoB-containing lipoproteins. For comparison, we also studied the risk of chronic limb-threatening ischemia and myocardial infarction. METHODS: apoB, remnant cholesterol, and LDL cholesterol were measured in 93 461 individuals without statin use at baseline from the Copenhagen General Population Study (2003-2015). During up to 15 years of follow-up, 1207 had PAD, 552 had chronic limb-threatening ischemia, and 2022 had myocardial infarction in the Danish National Patient Registry. Remnant and LDL cholesterol were calculated from a standard lipid profile. Remnant and LDL particle counts were additionally measured with nuclear magnetic resonance spectroscopy in 25 347 of the individuals. Results were replicated in 302 167 individuals without statin use from the UK Biobank (2004-2010). RESULTS: In the Copenhagen General Population Study, multivariable adjusted hazard ratios for risk of PAD per 1 mmol/L (39 mg/dL) increment in remnant and LDL cholesterol were 1.9 (95% CI, 1.5-2.4) and 1.1 (95% CI, 1.0-1.2), respectively; corresponding results in the UK Biobank were 1.7 (95% CI, 1.4-2.1) and 0.9 (95% CI, 0.9-1.0), respectively. In the association from elevated apoB to increased risk of PAD, remnant and LDL cholesterol explained 73% (32%-100%) and 8% (0%-46%), respectively; corresponding results were 63% (30%-100%) and 0% (0%-33%) for risk of chronic limb-threatening ischemia and 41% (27%-55%) and 54% (38%-70%) for risk of myocardial infarction; results for remnant and LDL particle counts corroborated these findings. CONCLUSIONS: PAD risk conferred by elevated apoB-containing lipoproteins was explained mainly by elevated remnants, while myocardial infarction risk was explained by both elevated remnants and LDL.

Elevated plasma triglycerides increase the risk of psoriasis: a cohort and Mendelian randomization study.

BACKGROUND: It is increasingly clear that triglyceride-rich lipoproteins are proinflammatory and cause low-grade systemic inflammation. However, it is currently unknown whether elevated plasma triglycerides are causally related to the development of psoriasis, a skin disorder driven by chronic inflammation. OBJECTIVES: To determine if elevated plasma triglycerides are associated with increased risk of psoriasis in observational and Mendelian randomization analysis. METHODS: Consecutive individuals from the Copenhagen General Population Study were included. We used plasma triglycerides (n = 108 043) and a weighted triglyceride allele score (n = 92 579) on nine known triglyceride-altering genetic variants. Genetic results were replicated in 337 159 individuals from the UK Biobank. Psoriasis was defined using the International Classification of Diseases, version 10 (ICD-10) code for hospital contact in the main analyses, and prescription of topical antipsoriatics for mild psoriasis in the sensitivity analysis. RESULTS: During a follow-up of median (range) 9.3 (0.1-15.1) years from 2003 to 2015 through 2018, 855 (1%) individuals were diagnosed with psoriasis by ICD-10 in the observational analysis and 772 (1%) in the Mendelian randomization analysis. In the observational analysis, the multivariable adjusted hazard ratio for psoriasis by ICD-10 was 1.26 [95% confidence interval (CI) 1.15-1.39] per doubling in plasma triglycerides with a corresponding causal odds ratio of incident psoriasis of 2.10 (95% CI 1.30-3.38). Causality was confirmed from data from the UK Biobank. Results were similar but slightly attenuated when we used topical antipsoriatic prescriptions for mild psoriasis. CONCLUSIONS: Elevated plasma triglycerides are associated with an increased risk of psoriasis in observational and Mendelian randomization analysis.

Psoriasis is a common skin condition, characterized by inflammation in the body (the body's response to an unwanted agent). People with psoriasis often have higher lipid levels in their blood compared with people without psoriasis. Some studies have shown that triglyceride-rich lipoprotein (a certain type of lipid) is irritative to the body and can cause inflammation. However, it is unclear whether high levels of triglycerides in the blood can cause them to penetrate into the skin and trigger the onset of psoriasis. We aimed to test this question in 100,000 people from a Danish population without previously diagnosed psoriasis. Specifically, we measured plasma triglycerides at initial examination and at the same time assessed the same people for genetic variants that impact on the concentration of plasma triglycerides. Importantly, genetic variants are inherited by chance, meaning that we could look specifically at whether a change in triglycerides was the mechanism that causes psoriasis. Next, we observed these people for about 10 years and noted any new occurrence of psoriasis during follow-up. We found that the risk of developing psoriasis was higher both as a function of plasma triglyceride concentration and the genetic variants that increase plasma triglyceride concentration. Overall, our study findings suggest that high levels of triglycerides in the blood could be a causal risk factor for the development of psoriasis.

Elevated remnant cholesterol, plasma triglycerides, and cardiovascular and non-cardiovascular mortality.

AIMS: Cholesterol carried in triglyceride-rich lipoproteins, also called remnant cholesterol, is being increasingly acknowledged as an important causal risk factor for atherosclerosis. Elevated remnant cholesterol, marked by elevated plasma triglycerides, is associated causally with an increased risk of atherosclerotic cardiovascular disease. The association with cause-specific mortality is, however, unclear. The aim of this study was to test the hypothesis that elevated remnant cholesterol and plasma triglycerides are associated with increased mortality from cardiovascular disease, cancer, and other causes. METHODS AND RESULTS: Using a contemporary population-based cohort, 87 192 individuals from the Copenhagen General Population Study aged 20-69 years at baseline in 2003-2015 were included. During up to 13 years of follow-up, 687 individuals died from cardiovascular disease, 1594 from cancer, and 856 from other causes, according to the National Danish Causes of Death Registry. In individuals with remnant cholesterol ≥1.0 mmol/L (≥39 mg/dL; 22% of the population) compared with those with levels <0.5 mmol/L (<19 mg/dL), multivariable-adjusted mortality hazard ratios were 2.2 (95% confidence interval 1.3-3.5) for cardiovascular disease, 1.0 (0.7-1.3) for cancer, and 2.1 (1.4-3.3) for other causes. Exploratory analysis of the cause of death subcategories showed corresponding hazard ratios of 4.4 (1.6-11) for ischemic heart disease, 8.4 (2.0-34) for infectious diseases, and 9.1 (1.9-43) for endocrinological diseases. Results for plasma triglycerides >2 vs. <1 mmol/L (>177 vs. <89 mg/dL) were similar. CONCLUSION: Remnant cholesterol of ≥1 mmol/L (39 mg/dL), present in 22% of the population, and plasma triglycerides of ≥2 mmol/L (177 mg/dL), present in 28% of the population, were associated with two-fold mortality from cardiovascular and other causes, but not from cancer. This novel finding should be confirmed in other cohorts.

Inflammation compared to low-density lipoprotein cholesterol: two different causes of atherosclerotic cardiovascular disease.

PURPOSE OF REVIEW: Inflammation is gaining attention as a target for prevention of atherosclerotic cardiovascular disease (ASCVD). The purpose of this review is to compare the evidence for inflammation with the evidence for low-density lipoprotein (LDL) cholesterol in ASCVD. RECENT FINDINGS: Evidence from human genetic studies and randomized controlled trials implicate the inflammatory pathway from the inflammasome through interleukin (IL)-1 to IL-6 as a cause of ASCVD. Higher levels of IL-6 may lead to proportionally increased risk of ASCVD, and randomized controlled trials of IL-6 inhibitors are underway. The causal evidence for LDL cholesterol in ASCVD is overwhelming and recent important findings instead revolve around development of improved LDL cholesterol lowering therapy through RNA and DNA based therapeutics. Even though some lipid-lowering therapies lower IL-6, the IL-6 inflammatory pathway and LDL cholesterol are two separate causes of ASCVD. SUMMARY: IL-6 mediated inflammation most likely causes ASCVD, in parallel with LDL cholesterol. However, fewer individuals in the general population are exposed to high IL-6 than high LDL cholesterol. For inflammation, future research should focus on improving efficacy and safety of anti-inflammatory therapy, and for LDL cholesterol, future research should focus on wider and more effective implementation of LDL cholesterol lowering therapy.

Elevated remnant cholesterol and atherosclerotic cardiovascular disease in diabetes: a population-based prospective cohort study.

AIMS/HYPOTHESIS: Elevated remnant cholesterol is observationally and causally associated with increased risk of atherosclerotic cardiovascular disease (ASCVD) in the general population. This association is not well studied in individuals with diabetes, who are often included in clinical trials of remnant cholesterol-lowering therapy. We tested the hypothesis that elevated remnant cholesterol is associated with increased risk of ASCVD in individuals with diabetes. We also explored the fraction of excess risk conferred by diabetes which can be explained by elevated remnant cholesterol. METHODS: We included 4569 white Danish individuals with diabetes (58% statin users) nested within the Copenhagen General Population Study (2003-2015). The ASCVDs peripheral artery disease, myocardial infarction and ischaemic stroke were extracted from national Danish health registries without losses to follow-up. Remnant cholesterol was calculated from a standard lipid profile. RESULTS: During up to 15 years of follow-up, 236 individuals were diagnosed with peripheral artery disease, 234 with myocardial infarction, 226 with ischaemic stroke and 498 with any ASCVD. Multivariable adjusted HR (95% CI) per doubling of remnant cholesterol was 1.6 (1.1, 2.3; p=0.01) for peripheral artery disease, 1.8 (1.2, 2.5; p=0.002) for myocardial infarction, 1.5 (1.0, 2.1; p=0.04) for ischaemic stroke, and 1.6 (1.2, 2.0; p=0.0003) for any ASCVD. Excess risk conferred by diabetes was 2.5-fold for peripheral artery disease, 1.6-fold for myocardial infarction, 1.4-fold for ischaemic stroke and 1.6-fold for any ASCVD. Excess risk explained by elevated remnant cholesterol and low-grade inflammation was 14% and 8% for peripheral artery disease, 26% and 16% for myocardial infarction, 34% and 34% for ischaemic stroke, and 24% and 18% for any ASCVD, respectively. LDL-cholesterol did not explain excess risk, as it was not higher in individuals with diabetes. We also explored the fraction of excess risk conferred by diabetes which can be explained by elevated remnant cholesterol. CONCLUSIONS/INTERPRETATION: Elevated remnant cholesterol was associated with increased risk of ASCVD in individuals with diabetes. Remnant cholesterol and low-grade inflammation explained substantial excess risk of ASCVD conferred by diabetes. Whether remnant cholesterol should be used as a treatment target remains to be determined in randomised controlled trials.

Do Triglyceride-Rich Lipoproteins Equal Low-Density Lipoproteins in Risk of ASCVD?

PURPOSE OF REVIEW: Recent large clinical trials have failed to show that triglyceride-rich lipoprotein-lowering therapies decrease the risk of atherosclerotic cardiovascular disease (ASCVD). In this review, we reconcile these findings with evidence showing that elevated levels of triglyceride-rich lipoproteins and the cholesterol they contain, remnant cholesterol, cause ASCVD alongside low-density lipoprotein (LDL) cholesterol. RECENT FINDINGS: Results from observational epidemiology, genetic epidemiology, and randomized controlled trials indicate that lowering of remnant cholesterol and LDL cholesterol decrease ASCVD risk by a similar magnitude per 1 mmol/L (39 mg/dL) lower non-high-density lipoprotein cholesterol (remnant cholesterol+LDL cholesterol). Indeed, recent guidelines for ASCVD prevention recommend the use of non-high-density lipoprotein cholesterol instead of LDL cholesterol. Current consensus is moving towards recognizing remnant cholesterol and LDL cholesterols as equals per 1 mmol/L (39 mg/dL) higher levels in the risk assessment of ASCVD; hence, triglyceride-rich lipoprotein-lowering therapies should also lower levels of non-HDL cholesterol to reduce ASCVD risk.

APOC3 Loss-of-Function Mutations, Remnant Cholesterol, Low-Density Lipoprotein Cholesterol, and Cardiovascular Risk: Mediation- and Meta-Analyses of 137 895 Individuals.

OBJECTIVE: Loss-of-function mutations in APOC3 associate with low remnant cholesterol levels and low risk of ischemic vascular disease (IVD). Because some studies show an additional association with low levels of low-density lipoprotein cholesterol (LDL-C), low LDL-C may explain the low risk of IVD in APOC3 loss-of-function heterozygotes. We tested to what extent the low risk of IVD in APOC3 loss-of-function heterozygotes is mediated by low plasma remnant cholesterol and LDL-C. APPROACH AND RESULTS: In APOC3 loss-of-function heterozygotes versus noncarriers, we first determined remnant cholesterol and LDL-C levels in meta-analyses of 137 895 individuals. Second, we determined whether the association with LDL-C was masked by lipid-lowering therapy. Finally, using mediation analysis, we determined the fraction of the low risk of IVD and ischemic heart disease mediated by remnant cholesterol and LDL-C. In meta-analyses, remnant cholesterol was 43% lower (95% confidence interval, 40%-47%), and LDL-C was 4% lower (1%-6%) in loss-of-function heterozygotes (n=776) versus noncarriers. In the general population, LDL-C was 3% lower in loss-of-function heterozygotes versus noncarriers, 4% lower when correcting for lipid-lowering therapy, and 3% lower in untreated individuals (P values, 0.06-0.008). Remnant cholesterol mediated 37% of the observed 41% lower risk of IVD and 54% of the observed 36% lower risk of ischemic heart disease; corresponding values mediated by LDL-C were 1% and 2%. CONCLUSIONS: The low risk of IVD observed in APOC3 loss-of-function heterozygotes is mainly mediated by the associated low remnant cholesterol and not by low LDL-C. Furthermore, the contribution of LDL-C to IVD risk was not masked by lipid-lowering therapy. This suggests APOC3 and remnant cholesterol as important new targets for reducing cardiovascular risk.